EP1507016A1 - Niedrig gekohlter Automatenstahl. - Google Patents

Niedrig gekohlter Automatenstahl. Download PDF

Info

Publication number
EP1507016A1
EP1507016A1 EP04254607A EP04254607A EP1507016A1 EP 1507016 A1 EP1507016 A1 EP 1507016A1 EP 04254607 A EP04254607 A EP 04254607A EP 04254607 A EP04254607 A EP 04254607A EP 1507016 A1 EP1507016 A1 EP 1507016A1
Authority
EP
European Patent Office
Prior art keywords
mns
inclusions
steel
carbide
substantial
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP04254607A
Other languages
English (en)
French (fr)
Other versions
EP1507016B1 (de
Inventor
Naoki Sumitomo Metal Industries Ltd. Matsui
Takayuki Sumitomo Metal Industries Ltd. Nishi
Toru Sumitomo Metal Industries Ltd. Kato
Koji Sumitomo Metal Industries Ltd. Watari
Tatsuya Sumitomo Metals Hasegawa (Kokura) Ltd.
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Sumitomo Metal Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Metal Industries Ltd filed Critical Sumitomo Metal Industries Ltd
Publication of EP1507016A1 publication Critical patent/EP1507016A1/de
Application granted granted Critical
Publication of EP1507016B1 publication Critical patent/EP1507016B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • This invention relates to a low-carbon free cutting steel which is free of lead (Pb).
  • Pb lead
  • a low-carbon free cutting steel which, when machined with a carbide tool, has superior machinability compared to conventional leaded free cutting steels and composite free cutting steels in which lead and one or more machinability improving elements are used together, in spite of its being free of lead, and also which has excellent hot workability and finished surface characteristics after machining, and can be produced at a low cost.
  • the present invention also relates to a low-carbon free cutting steel excellent, not only in the above-mentioned characteristics, but also in carburizing characteristics.
  • the best known free cutting steels include resulfurized free cutting steels which are improved in machinability by MnS due to the addition of a large amount of S; leaded free cutting steels obtained by an addition of Pb; and composite free cutting steels containing both of S and Pb.
  • leaded free cutting steels are characterized in that they contribute toward prolonging the tool life and are excellent in chip disposability and also in that the steel products after machining are excellent in surface roughness, etc.
  • such parts as mentioned above after being completed to a desired shape and form by machining, are subjected to carburizing in order to secure a desired level of surface strength. Therefore, the steel material to be used in manufacturing such parts is sometimes required, not only to have high machinability, but also to be excellent in carburizing characteristics.
  • Patent Document 1 Japanese Patent Laid-open Application (JP Kokai) 2003-49240 (Patent Document 1), there is disclosed a free cutting steel improved in machinability, by causing Ti and/or Zr carbosulfide type inclusions to exist therein. Since the Ti carbosulfide or the Zr carbosulfide is dispersed, together with MnS, in this free cutting steel, the pseudo lubricating effect of the MnS can hardly be obtained and the frictional force between the tool and the work material increases. As a result, the cutting force increases and a built-up edge formation on the edge of cutting tool is facilitated. Once a built-up edge has been formed, the finished surface roughness after finish machining increases and the working precision of the parts is impaired.
  • Patent Document 1 no example is given of the case where the Ti content is 0.1% or less. This indicates that the invention disclosed in Patent Document 1 aims at forming Ti carbosulfide inclusions by causing a large amount of Ti to be contained in the steel. Actually, it is described therein that the Ti carbosulfide type inclusions, together with MnS, are dispersed in a granular form in the matrix. In this case, those performance characteristics, such as tool life, chip disposability and low-level finished surface roughness, which are required in the steel to be used in manufacturing the parts mentioned above, cannot be acquired.
  • Patent Document 2 JP Kokai 2003-49241 discloses a free cutting steel containing Ti and/or Zr within the content range of (Ti + 0.52 Zr)/S ⁇ 2, containing Ti or Zr carbosulfide as an inclusion component and contributing to a prolonged tool life in turning and drilling.
  • the invention described in Patent Document 2 aims at improving the tool life in turning by causing a formation of Ti carbosulfide in the steel.
  • This technology can indeed improve the tool life to a certain extent but the presence of Ti or Zr carbosulfide makes it difficult to obtain the lubricating effect of the MnS, hence the frictional force between the tool and the work material increases. As a result, the cutting force increases and a built-up edge formation on the edge of cutting tool is facilitated. Once a built-up edge has been formed, the finished surface roughness after cutting increases, with the result that the working precision of the parts is impaired.
  • Patent Document 2 there is no example found of the free cutting steel containing S in the range of not lower than 0.21% and Ti at a level not higher than 0.1%, as specified later herein in relation to the present invention. Due to this, it is evident that the invention in Patent Document 2 is not an invention aiming at improving the finished surface roughness and/or chip disposability. According to the invention in Patent Document 2, Ti or Zr carbosulfide, together with MnS, is dispersed in the matrix and, therefore, the desired level of finished surface roughness and of chip disposability cannot be attained.
  • JP Kokai 2000-319753 there is disclosed a low-carbon resulfurized free cutting steel in which the amount of MnS is increased through an S content exceeding 0.4% to which Pb is not added.
  • this steel is low in improving the tool life of carbide tools. Further, there is no improvement in chip disposability, which is important, nor in performance characteristics, as compared with the conventional resulfurized free cutting steels.
  • JP Kokai H09-53147 discloses a free cutting steel excellent in carbide tool machinability and, in particular, in tool life, which contains C: 0.01-0.2%, Si: 0.10-0.60%, Mn: 0.5-1.75%, P: 0.005-0.15%, S: 0.15-0.40%, O (oxygen): 0.001-0.010%, Ti: 0.0005-0.020% and N: 0.003-0.03%.
  • This invention aims at improving the carbide tool life only due to the content of 0.1-0.6% of Si, together with Ti, as the essential components.
  • this invention does not aim at improving the tool life or the chip disposability or the finished surface roughness level because of the "substantial MnS with Ti carbide and/or Ti carbonitride included therein" exists in the steel without adding Si, as included in the present invention.
  • Japanese Patent No. 3390988 discloses an invention relating to a low-carbon resulfurized free cutting steel improved in mechanical anisotropy which contains C: 0.02-0.15%, Mn: 0.3-1.8%, S: 0.225-0.5%, Ti: 0.1-0.6% and Zr: 0.1-0.6%, with the proviso that Ti + Zr: 0.3-0.6% and (Ti + Zr)/S ratio: 1.1-1.5.
  • the steel of this invention is improved in mechanical anisotropy and machinability by employing the above composition to cause a formation of Ti and/or Zr sulfide, which are high in hot deformation resistance.
  • Another objective of the present invention is to provide a low-carbon free cutting steel, having good carburizing characteristics, in addition to the characteristics mentioned above.
  • the states of inclusions exert great influences on the machinability of steels.
  • Various inclusions are observed in steels containing C, Ti, S, N and O.
  • this includes Ti sulfide, Ti carbosulfide, Ti carbide, Ti carbonitride, Ti nitride and Ti oxide.
  • Mn Mn sulfide represented by the chemical formula "MnS" is also present.
  • Al and/or Si are contained in addition to those elements mentioned above, the oxides thereof are also present.
  • the states of these inclusions are diverse, and the compositions and the states of these inclusions greatly influence the machinability and other mechanical characteristics of steels.
  • the steel according to this senior invention is much better in tool life than leaded free cutting steels and shows good chip disposability.
  • This steel still has some drawbacks with respect to its surface characteristics after machining. Namely, it has been revealed that when the finish machining was carried out, the finished surface roughness became large in some instances.
  • substantially Ti sulfide and/or Ti carbosulfide as used herein means those inclusions in each of which the total area in percent occupied by Ti sulfide and Ti carbosulfide amounts to not less than 50%. Some of them are shown in Fig. 1A attached hereto.
  • the present inventors made investigations to solve this problem and, as a result, obtained new findings as mentioned below.
  • a low-carbon resulfurized free cutting steel that is characterized by comprising C: 0.05 to under 0.20%, Mn: 0.4-2.0%, S: 0.21-1.0%, Ti: 0.002-0.10%, P: 0.001-0.30%, Al: not higher than 0.2%, O (oxygen): 0.001-0.03% and N: 0.0005-0.02%, with the balance being Fe and impurities, and which satisfies the relations (a) and (b) given below concerning the inclusions contained in the steel.
  • (A + B)/C ⁇ 0.8 N A ⁇ 5 where A, B, C and N A denote as follows:
  • the above low-carbon free cutting steel may contain one or more components selected from at least one group out of the following first to third groups:
  • substantially MnS with Ti carbide and/or Ti carbonitride included therein means those inclusions in each of which the area percentage of MnS amounts to not less than 50% and Ti carbide and/or Ti carbonitride are included (i.e. coexist).
  • substantially MnS with neither Ti carbide nor Ti carbonitride included therein means those inclusions in each of which the area percentage of MnS amounts to not less than 50% and neither Ti carbide nor Ti carbonitride are included (i.e. coexist).
  • the main characteristic features of the low-carbon free cutting steel of the present invention are as follows:
  • Si and Cr are dissolved in austenite and this increases the hardenability of steels and thereby increases the depth of carburizing and the hardness of the carburized layer in the carburizing treatment.
  • Si and Cr there are other hardenability increasing elements, for example Mn, Mo and P.
  • Mn is required to be added at a sufficiently high level relative to the content of S.
  • the addition of a further amount of Mn for hardenability improvement only means an additional cost.
  • Mo is effective in increasing the hardenability of the steels but is more expensive than Si or Cr, hence the addition of Mo in an equally effective amount results in an increase in production cost.
  • P also has the same effect but the addition thereof results in a rapid increase in hardness of the steels themselves, hence in the deterioration in machinability.
  • these elements may be added at levels not leading to deterioration in machinability or in mechanical properties.
  • Si and Cr are desirous as carburization characteristics improving elements when the desired steels are to be produced at a low cost without deterioration in machinability.
  • Ti binds to S, C, N and O to form Ti sulfide and Ti carbosulfide represented by the chemical formulas such as TiS and Ti 4 C 2 S 2 , as well as Ti-based inclusions such as Ti carbide, Ti carbonitride, Ti nitride and Ti oxide represented by the chemical formulas TiC, Ti(CN), TiN and TiO, respectively.
  • Ti is dissolved in MnS and exists as (Mn,Ti)S; since, however, the solubility of Ti in MnS is low, this sulfide is substantially MnS.
  • Ti is not dissolved in MnS but exists as a phase distinct from MnS. Then Ti exists in the form of TiC and/or Ti(C, N), namely in a form distinctly different in composition from MnS, and the mode of existence thereof is diversified, for example in the vicinity around one sulfide, or surrounded by MnS.
  • Fig. 1A is a schematic representation of inclusions existing in a Ti-containing free cutting steel for comparison, and Fig. 1B in a free cutting steel according to the present invention.
  • substantially MnS with neither Ti carbide nor Ti carbonitride included therein includes MnS in those inclusions in each of which such a Ti-based inclusion other than Ti carbide and Ti carbonitride as mentioned above, or some other element-based oxide, nitride, carbide or like compound and MnS exist in distinctly separate phases, and the area percentage of MnS is not less than 50%, and which substantially play the role as MnS, and MnS entirely free of the above-mentioned Ti-based inclusions or other element-based oxide, nitride, carbide, etc.
  • the sum of “substantial MnS with Ti carbide and/or Ti carbonitride included therein” and “substantial MnS with neither Ti carbide nor Ti carbonitride included therein” represents the sum of inclusions regarded substantially as MnS (the above-mentioned "substantial MnS” species) while the other inclusions include Ti-based inclusions such as Ti sulfide, Ti carbosulfide, Ti carbide, Ti carbonitride, Ti nitride, and Ti oxide, and other element-based oxides, carbides and nitrides, etc.
  • the above-mentioned area percentage of MnS and Ti-based inclusions in one inclusion can be understood by area analysis and quantitative analysis, using an EPMA (electron probe microanalyzer), an EDX (energy dispersive X-ray microanalyzer) or the like, of a microstructure test specimen cut out from a round bar to be subjected to a machining test.
  • EPMA electron probe microanalyzer
  • EDX energy dispersive X-ray microanalyzer
  • A is the total area occupied by "substantial MnS with Ti carbide and/or Ti carbonitride included therein” among the inclusions not smaller than 1 ⁇ m in circle-equivalent diameter per mm 2 of a cross section parallel to the direction of rolling.
  • B is the total area occupied by "substantial MnS with neither Ti carbide nor Ti carbonitride included therein” among the inclusions not smaller than 1 ⁇ m in circle-equivalent diameter per mm 2 of a cross section parallel to the direction of rolling.
  • the term “circle-equivalent diameter” indicates the diameter resulting from the conversion of the area of one inclusion as determined by the technique mentioned above, for example by image analysis, to a circle having the same area. The restriction "not smaller than 1 ⁇ m in circle-equivalent diameter” is applied since those inclusions which are smaller than 1 ⁇ m exert little influence on the machinability.
  • the expression (a) given above indicates that it is necessary for the sum of A and B to be not less than 80% of the total area occupied by all the inclusions not smaller than 1 ⁇ m in circle-equivalent diameter. Although good machinability can be obtained within this range, a more preferred lower limit is 90%.
  • the inclusions other than the inclusions represented by A and B include independently existing nitrides, carbides, oxides, "substantial Ti sulfide and/or Ti carbosulfide", etc.
  • the expression (a) indicates that the total area of such inclusions other than "substantial MnS" should be lower than 20% of the total area (i.e. C in expression (a)) occupied by all inclusions. More preferably, the total area in question is less than 10%.
  • Ti When Ti is added to a steel containing a large amount of S for the purpose of machinability improvement; Ti, which has a stronger tendency toward sulfide formation than Mn, readily forms Ti sulfide and/or Ti carbosulfide.
  • the expression (a), specified in accordance with the present invention aims at preventing the formation of Ti sulfide and Ti carbosulfide on the assumption that Ti is added. This is because Ti sulfide and Ti carbosulfide interfere with the pseudo lubricating effect of MnS during machining.
  • the steel when the steel composition range specified in accordance with the present invention is employed and the expression (a) is satisfied, the steel can be at least comparable in the finished surface roughness level in finish machining to the conventional leaded free cutting steels and composite free cutting steels.
  • the expression (a) when the expression (a) is not satisfied even if the chemical composition is within the range specified in accordance with the present invention, good machinability cannot be obtained.
  • N A is "the number of substantial MnS inclusions with Ti carbide and/or Ti carbonitride included therein among the inclusions not smaller than 1 ⁇ m in circle-equivalent diameter per mm 2 of a cross section parallel to the direction of rolling".
  • the term “substantial MnS inclusions with Ti carbide and/or Ti carbonitride included therein” indicates those inclusions in each of the area percentage of MnS is not less than 50%, as mentioned hereinabove.
  • the "substantial MnS with Ti carbide and/or Ti carbonitride included therein” does not substantially impair the pseudo lubricating effect, hence the built-up edge hardly forms and the finished surface roughness feature of the machined material will not deteriorate.
  • the existence of the hard TiN in a laminar form can be confirmed by an area analysis and a point quantitative analysis, by AES (Auger electron spectroscopy) or using an EPMA (electron probe microanalyzer), of the tool surface deprived of carbon-containing contaminants (e.g. oils and fats etc.) by Ar sputtering or the like after completion of machining.
  • AES Alger electron spectroscopy
  • EPMA electrostatic microanalyzer
  • the hard TiN formed on the tool surface prevents tool wear, such as a thermal diffusion wear and a mechanical friction wear due to the hard inclusions, so that a markedly superior tool life, compared with the conventional resulfurized free cutting steels and Pb-containing composite free cutting steels, can be obtained.
  • MnS exists in a very fine form.
  • the number of MnS inclusions is very large.
  • Ti is added in a large amount relative to the amount of S, namely if the Ti/S ratio exceeds 0.25, Ti sulfide and Ti carbosulfide will exist in large amounts. As a result, the expression (a) is not satisfied, and the pseudo lubricating effect of MnS will be reduced. On such occasion, the cutting force tends to increase and the built-up edge formation on the edge of cutting tool easily tends to occur resulting in deterioration in surface roughness characteristics in the finish machining and in working precision.
  • Ti carbide and Ti carbonitride precipitate in various forms they exist in a form included in MnS in some instances.
  • a steel containing "substantial MnS with Ti carbide and/or Ti carbonitride included therein” is machined in high-speed range using a carbide tool, a satisfactory tool life can be obtained.
  • the Ti (%)/S (%) ratio should be adjusted to 0.25 or below so that the formation of singly existing inclusions consisting of "substantial Ti sulfide and/or Ti carbosulfide" may be prevented.
  • the main sulfide product is not MnS but mainly Ti sulfide and/or Ti carbosulfide, which are harder than MnS, because Ti has a stronger tendency toward sulfide formation than Mn.
  • the soft sulfide-due pseudo lubricating effect between the tool and work material during machining cannot be obtained, but the cutting force increases, resulting in deterioration in surface roughness level, as mentioned above.
  • the free cutting steel of the present invention contains "substantial MnS with Ti carbide and/or Ti carbonitride included therein".
  • this "substantial MnS with Ti carbide and/or Ti carbonitride included therein” cannot be obtained in a sufficient amount.
  • the ratio Ti (%)/N (%) is desirably not less than 1.35 and, in order to stably obtain "substantial MnS with Ti carbide and/or Ti carbonitride included therein", the ratio Ti (%)/N (%) is more preferably not less than 1.5.
  • C is an important element exerting a great influence on the machinability C content of 0.20% or above increases the strength of the steel but deteriorates its machinability, thus rendering the steel inappropriate to use where the machinability is regarded as important.
  • a C content level under 0.05% however, the steel becomes excessively soft, allowing the occurrence of plucking during machining, and the wear on the tool is promoted and the finished surface roughness increases. Therefore, an adequate content of C is 0.05 to under 0.20%. A more adequate C content for obtaining better machinability is within the range of 0.07-0.18%.
  • Mn is an important element which forms sulfide inclusions with S and thus exerts a great influence on the machinability. At a Mn content level less than 0.4%, the absolute quantity of the sulfide is insufficient, therefore a satisfactory level of machinability cannot be obtained. Since Mn is an element increasing the hardenability of steels, the content of Mn may be increased when it is desired to obtain good carburizing characteristics. However, it is necessary for the steel of the present invention, which contains a large amount of S, to contain a large amount of Mn so that the Mn may form MnS with S. The addition of Mn for improving the carburizing characteristics means a further addition to the Mn content and therefore is undesirable from a production cost viewpoint.
  • the upper limit of the Mn content is set to 2.0%.
  • the strength of the steel increases and, accordingly, the cutting force increases, so that the tool life is shortened.
  • the relationship with the content of S is important. Therefore in order to ensure those performance characteristics, the Mn content is preferably within the range of 0.6 - 1.8%.
  • S is an element capable of forming sulfide inclusions with Mn and thus effective in machinability improvement.
  • the machinability improving effect of MnS increases with the increase in the amount of S and, therefore, the selection of the S content level is important.
  • S content level below 0.21%, it is impossible to obtain a sufficient amount of sulfide inclusions, hence no satisfactory machinability can be expected.
  • S contents exceeding 0.35% deteriorate the hot workability and promote the segregation of S in the center of the steel ingot and induce cracking in a step of forging. By maintaining an appropriate composition, however, it is possible to increase the upper limit to 1.0%.
  • a further amount of S is added preferably to a level of not lower than 0.35%.
  • An addition level exceeding 0.40% is still more preferred for further machinability improvement.
  • an excessive addition level results in an increase in production cost due to a decrease in yield. Therefore, a preferred upper limit to the S content is 0.70%.
  • Ti is an indispensable and important element for forming Ti carbide and/or Ti carbonitride with N and/or C, causing the MnS, which includes them, to exist in the steel.
  • substantially MnS with Ti carbide and/or Ti carbonitride included therein exists in the steel, the tool life of the high-speed machining using a carbide tool is markedly improved, as described above.
  • a Ti content not lower than 0.002% is required. In order to stably disperse it in the steel and obtaining a satisfactory tool life without deterioration in the finished surface roughness level, it is necessary to take the balance between the Ti content and the contents of S and N into consideration.
  • the upper limit of the Ti content is set to 0.10%.
  • the Ti content is preferably not higher than 0.08%, more preferably less than 0.03%.
  • the content of P increases the hardenability of the steel and at the same time increases the strength.
  • the content of P should be not lower than 0.001%.
  • the hardenability and strength can be secured without deteriorating the machinability.
  • the strength becomes excessively high and the machinability is somewhat deteriorated and, in addition, the hot workability is deteriorated through promoted segregation in the steel ingot. Therefore, the content of P should be 0.001-0.30%.
  • a more preferred content of P for stably maintaining good machinability and strength levels is 0.005 - 0.13%.
  • Al is used as a potent deoxidizing element and may be contained up to a level of 0.2%.
  • the oxide formed upon deoxidation is hard and, when the content of Al exceeds 0.2%, the hard oxide is formed in large amounts, deteriorating the machinability. Therefore, content of not more than 0.1% is more preferred.
  • Al may not be added and the content of Al may have an impurity level not higher than 0.002%.
  • oxygen When an appropriate amount of oxygen is contained in the steel, it is dissolved in the MnS and this prevents the elongation of MnS upon rolling and thus reduces the anisotropy in mechanical properties, although the effects of the oxygen in the steel of the present invention are not affected by the state of the deoxidation. Further, oxygen is also effective in improving the machinability and hot workability and also prevents the segregation of S. However, at an O content level exceeding 0.03%, it causes problems; for example, it causes deterioration of and damage to the refractory material in the melting stage. Therefore, the oxygen content should be within the range of 0.001 - 0.03%. A preferred range for properly obtaining the above effects is 0.0015 - 0.01%.
  • N easily forms hard nitrides with Al and/or Ti. These nitrides are effective in making grains finer. However, when present in large amounts, these nitrides tend to promote the wear of the tool and deteriorate the machinability Since Ti is added, as an essential component, to the steel of the present invention, the content of N should preferably be as low as possible. However, for obtaining the above effect, N is allowable to be contained at a level of not lower than 0.0005%. When, on the other hand, the content of N becomes excessive, coarse TiN may be formed, possibly impairing the machinability, hence the upper limit of the N content is set to 0.02%. For securing better machinability, the upper limit of the N content is preferably set to 0.015%.
  • the present invention aims at improving the machinability by the occurrence of "substantial MnS with Ti carbide and/or Ti carbonitride included therein", it is desirable that the contents of Ti and N satisfy the condition of Ti (%)/N (%) ⁇ 1.35 so that such MnS may exist stably in the steel. This is because when Ti (%)/N (%) ⁇ 1.35, most of Ti added forms TiN in the early stage of solidification and, as a result, "substantial MnS with Ti carbide and/or Ti carbonitride included therein” cannot be stably obtained, as described hereinabove.
  • the low-carbon free cutting steel of the present invention may further contain one or more elements selected from at least one group among the first to third groups mentioned hereinabove (refer to page 9).
  • the elements of the first group are elements capable of further improving the machinability of the steel without impairing the effects obtained by the above-mentioned main composition according to the present invention. Therefore, for obtaining further improved machinability, one or more of them may be contained in the steel.
  • Se and Te form Mn(S, Se) and Mn(S, Te) with Mn. These play the same role as that of MnS in producing the pseudo lubricating effect during machining and, therefore, Se and Te are elements which are effective in machinability improvement and, for further machinability improvement, they may be contained in the steel within the above respective ranges. When their content levels are below 0.0005%, their effects are insignificant. On the other hand, at levels exceeding 0.10%, not only the effect of each of the Se and Te reaches a point of saturation but also due to the addition it becomes uneconomical, and also the hot workability deteriorates. For simultaneously obtaining good hot workability and more stable machinability, the additional level of each element is preferably 0.0010 - 0.05%.
  • Bi and Sn are effective in improving the machinability of the steel. This is presumably because they produce a lubricating effect during the machining as low-melting metal inclusions, similar to Pb.
  • the content of each is preferably set to not lower than 0.01%.
  • the addition level of each of them exceeds 0.30%, however, not only the effect of each of them reaches a point of saturation but also the hot workability deteriorates.
  • the additional level of each element is preferably 0.03 - 0.1%.
  • Ca has a high affinity for S and O (oxygen) and forms the corresponding sulfide and oxide in the steel. Further, Ca is dissolved in MnS to form (Mn, Ca) S but the amount of Ca soluble therein is slight, hence the effects of MnS are not impaired.
  • the oxide formed by Ca is a low-melting oxide and, thus, Ca is an additive element effective in further improving the machinability of the steel of the present invention.
  • the lower limit of the Ca content is preferably set to 0.0001%. Since, however, the yield of the additional Ca is low, the addition of large amounts of Ca is required and, this is unfavorable from the production cost viewpoint. Therefore, the upper limit to the Ca content is set to 0.01%. A more preferred upper limit is 0.005%.
  • Mg also has a high affinity for S and O (oxygen) in the steel and forms the corresponding sulfide and oxide.
  • the Mg-containing sulfide and oxide function as nucleating agents in the crystallization of MnS and are effective in preventing the elongation of MnS.
  • Mg may be added.
  • the lower limit of the Mg content is preferably set to not lower than 0.0001%. Since, however, the oxide formed by Mg is hard, and excessively high Mg content deteriorates machinability Therefore, the upper limit of the Mg content is set to 0.005%.
  • a preferred upper limit for preventing the elongation of MnS and simultaneously obtaining good machinability is 0.002%.
  • B binds to O (oxygen) or N to form the oxide or nitride and is effective in the improvement of machinability, hence may be added according to need.
  • the B content of not lower than 0.0002% is required and in order to be more effective, a level of not lower than 0.0010% is desirable.
  • a B content level exceeding 0.02% that effect reaches a point of saturation and, in addition, the hot workability is somewhat deteriorated.
  • Rare earth elements constitute a group of elements classified as lanthanoids. When they are added, a misch metal or the like containing them as main components is generally used.
  • the content of rare earth elements so referred to herein, is expressed in terms of the total content of one or more elements among the rare earth elements.
  • the rare earth elements form oxides with oxygen and also bind to S to form sulfides, and thereby improve the machinability. In order to be effective, their content should be not less than 0.0005%. However, at content levels exceeding 0.02%, the effect reaches a point of saturation. Further, the yield of the addition of rare earth elements is low, hence the addition of rare earth elements in large amounts is uneconomical.
  • the elements of the second group all increase the strength of steel.
  • the steel may contain one or more of these elements according to need.
  • Cu is effective in improving the strength of the steel through precipitation hardening.
  • a Cu content of not less than 0.01% is required and an addition level of not lower than 0.1% is desirable.
  • the hot workability deteriorates.
  • the above effect reaches a point of saturation due to the coarsening of the Cu precipitates. In addition, this brings about a decrease in machinability.
  • Ni is effective in improving the strength of the steel through solid-solution strengthening.
  • its content is preferably not lower than 0.01%.
  • the machinability deteriorates and, at the same time, the hot workability also deteriorates.
  • Mo is an element capable of improving hardenability, but when Mo is added in an amount sufficient to produce the carburizing characteristics equivalent to that obtainable by the addition of Si and/or Cr, the production cost disadvantageously increases since Mo is more expensive than Si or Cr. However, Mo is also effective in rendering the microstructure finer and improving the toughness, therefore when it is desired that these effects be produced, Mo may be added. In order to obtain the effects, a content of Mo of not less than 0.01% is desirable, however, at levels exceeding 0.5%, the effects reaches a point of saturation and, in addition, the steel production cost increases.
  • V precipitates as fine nitrides or carbonitrides and improves the strength of the steel. This effect can be obtained if the V content is not less than 0.005% but a V content of not less than 0.01% is preferred. At a V content level exceeding 0.5%, however, the above effect reaches a point of saturation and, in addition, the excessively formed nitride and/or carbide bring out a decrease in machinability.
  • Nb precipitates as fine nitrides or carbonitrides and improves the strength of the steel. This effect can be obtained if the Nb content is not less than 0.005% but a Nb content of not less than 0.01% is preferred. At a Nb content level exceeding 0.5%, however, the above effect reaches a point of saturation and, in addition, the excessively formed nitride and/or carbide bring out a decrease in machinability and the Nb addition at such level is also uneconomical.
  • the elements of the third group are elements either one or both of which may be contained in the steel when the carburizing characteristics thereof need improvement.
  • Si is effective in improving the strength of the steel and it is also effective in improving the hardenability of the steel.
  • the hardenability of the steel By increasing the hardenability of the steel, it becomes possible to also improve the carburizing characteristics which are desired in manufacturing automotive parts.
  • Si can be added at a level of not lower than 0.1% and in order to further improve the carburizing characteristics more reliably, a content level exceeding 0.6% is desirable.
  • the machinability is adversely affected, for example the hot workability deteriorates and the cutting force increases, because of solid solution hardening of the ferrite phase.
  • the oxygen content in the steel can be adjusted to an appropriate level by properly adding C, Mn and/or Al.
  • Cr is an element capable of improving the carburizing characteristics thereby increasing the hardenability of the steel through additional small amounts.
  • the steel shows improved carburizing characteristics; the carburized layer hardness, after carburizing treatment, is high, and the effective hardening depth can be increased.
  • the Cr content should be set to not less than 0.03% and when more reliable improvements in carburizing characteristics are desired, content exceeding 0.05% is desirable.
  • the machinability deteriorates and the production cost also increases.
  • the comparative steels Nos. 51 to 53 were poor in hot workability and cracking occurred during the forging, making it impossible to produce any forged bars; hence subsequent investigations were not performed with them.
  • test specimens for microscopic observation were taken from each of the forged bars at a site corresponding to Df/4 (Df: diameter of the forged bar) in the longitudinal sectional direction, and embedded in a resin and, after mirror-like polishing, photographed under an optical microscope magnified 400 times.
  • each test specimen was prepared for microscopic observation by cutting out from the forged bar at a site corresponding to Df/4 (Df is the diameter of each forged bar) in a longitudinal sectional direction, embedded in a resin, mirror-like polished and then was subjected to area analysis and quantitative analysis using an EPMA (electron probe microanalyzer), an EDX (energy dispersive X-ray spectroscope), etc.
  • EPMA electron probe microanalyzer
  • EDX energy dispersive X-ray spectroscope
  • the magnification for observation had a range not exceeding 10,000 times and, at the selected observation magnification, an inclusion in which MnS and Ti carbide and/or Ti carbonitride were observed in distinctly separated phases, and in which the area percentage of MnS was not lower than 50%, corresponds to "substantial MnS with Ti carbide and/or Ti carbonitride included therein".
  • the areas of "substantial MnS with Ti carbide and/or Ti carbonitride included therein” and “substantial MnS with neither Ti carbide nor Ti carbonitride included therein” were determined for individual inclusions having a circle-equivalent diameter of not smaller than 1 ⁇ m. Then, the sums of the areas of these inclusions per mm 2 in the section in the direction of rolling were calculated and, the sum of the areas occupied by these inclusions per mm 2 in the section in the direction of rolling was calculated, and then (A + B)/C was calculated.
  • the number of inclusions consisting of "substantial MnS with Ti carbide and/or Ti carbonitride included therein” was determined.
  • the relevant steel was evaluated as "O”.
  • the number of inclusions consisting of "substantial MnS with Ti carbide and/or Ti carbonitride included therein” was less than 5, the relevant steel was evaluated as " ⁇ ”.
  • the comparative steels Nos. 35 to 37 given in Table 2 are Ti-free leaded or resulfurized free cutting steels. They are substantially free of "substantial MnS with Ti carbide and/or Ti carbonitride included therein", hence such calculations were not carried out.
  • each forged bar was externally machined into a round bar with a diameter of 60 mm and was subjected to tests for tool life and finished surface roughness.
  • the tool life test was carried out using an uncoated JIS P20 carbide tool under the following dry turning conditions;
  • the mean flank wear (VB) was measured. For those test specimens showing a mean flank wear of not less than 200 ⁇ m within 30 minutes, the time required for arriving at such wear and the mean flank wear (VB) at that time were measured for each of the specimens.
  • the tool life evaluation was carried out using, as a measure, the time required for the mean flank wear (VB) to arrive at 100 ⁇ m.
  • the time required for the mean flank wear to arrive at 100 ⁇ m was calculated from the turning time-tool wear curve by the regression method.
  • the chip disposability was evaluated by collecting 200 representative chips among the chips discharged from test specimen, measuring their mass, and calculating the number of chips per unit mass.
  • the finished surface roughness is evaluated in terms of the surface roughness after machining, the surface of each machined material after machining, under the following conditions, was evaluated using a versatile instrument for the evaluation of surface texture.
  • the test for the evaluation of the finished surface roughness was carried out using a TiAlN multilayer-coated JIS K type carbide tool.
  • the cutting was carried out in the manner of wet turning using a lubricating oil of the aqueous emulsion type under the following condition;
  • the hot workability was evaluated in the following manner.
  • a test specimen, 10 mm in diameter and 130 mm in height for high-temperature tensile test was taken from each 150-kg steel ingot.
  • the steel ingot was produced in the same manner as mentioned above.
  • the test specimen was taken in the direction of the steel ingot height so that the specimen center might be close to the surface of the steel ingot, namely at a site of Di/8 (Di: the diameter of the steel ingot).
  • the specimen was heated to 1,250°C for 5 minutes by a direct charge of an electric current at a fixation distance of 110 mm, and cooled to 1,100°C at a cooling rate of 10°C/sec.
  • the tensile test was carried out at a strain rate of 10 -3 /sec. In the tensile test, the reduction of area at the site of breakage was determined and the hot workability was evaluated based thereon.
  • the carburizing test was carried out in the following manner. A cylindrical steel material, 24 mm in diameter and 50 mm in length, was used as the test specimen. This was taken from each of the above-mentioned normalized materials, 65 mm in diameter, at a site of R/2 (R: the radius of the normalized material). This test specimen was heated to 900°C for the carburizing treatment and then to 850°C for the diffusion treatment. In the above-mentioned carburizing step, the carbon potential (C.P.) value was 0.8% and the treatment time was 75 minutes. The C.P. value during diffusion treatment was 0.7% and the treatment time was 20 minutes. The test specimen after carburizing treatment was cooled in an oil bath at 80°C for quenching treatment. Finally, the test specimen was heated to 190°C and maintained at that temperature for 60 minutes for the tempering treatment. The method of evaluation for carburizing characteristics was as follows.
  • the test specimen after carburizing quenching and tempering, was measured for Vickers hardness distribution from the surface to the inside in the cross section at a site of 25 mm distant from the end of the test specimen (namely the center in the longitudinal direction).
  • the effective case depth after carburizing corresponding to Hv 400 was determined, and a judgment was made as to whether the value was greater or smaller than the value obtained with a conventional leaded composite free cutting steel.
  • the conventional leaded composite free cutting steel was the steel No. 25 shown in Table 2, and the effective case depth after carburizing thereof was 0.25 mm.
  • the steels Nos. 35 and 36 are composite free cutting steels, and the steel No. 37 is a resulfurized free cutting steel. At this time, these steels are regarded as highest in machinability.
  • Table 4 Fig. 2 and Fig. 3, the steels of the present invention are superior in tool life and finished surface roughness level.
  • the steels Nos. 1-34 according to the present invention have good hot workability, and are at least comparable to the composite free cutting steels and resulfurized steels, as shown in Table 3 in terms of the reduction of area in the high-temperature tensile test simulating the practical production in a continuous casting plant or the like, and thus are free of problems from the practical viewpoint.
  • the steels Nos. 12-17 according to the present invention shown in Table 1, contains at least one including Si and Cr within the specified content range in order to improve the carburizing characteristics. It is evident that these steels show good carburizing characteristics, in particular, among the steels of the present invention.
  • the free cutting steel of the present invention is comparable or superior in machinability to the conventional leaded free cutting steels and composite free cutting steels and, further, are excellent from the finished surface characteristics viewpoint.
  • the free cutting steel of the present invention contains Si and/or Cr, it shows good carburizing characteristics.
  • this steel is excellent in hot workability and can be produced at a low cost by continuous casting. It produces no environmental problems since it does not contain Pb. Therefore, it is very well suited for use as a raw material of various machine parts.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
EP04254607A 2003-08-01 2004-07-30 Niedrig gekohlter Automatenstahl. Expired - Lifetime EP1507016B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003285463A JP3918787B2 (ja) 2003-08-01 2003-08-01 低炭素快削鋼
JP2003285463 2003-08-01

Publications (2)

Publication Number Publication Date
EP1507016A1 true EP1507016A1 (de) 2005-02-16
EP1507016B1 EP1507016B1 (de) 2007-07-25

Family

ID=33562752

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04254607A Expired - Lifetime EP1507016B1 (de) 2003-08-01 2004-07-30 Niedrig gekohlter Automatenstahl.

Country Status (7)

Country Link
US (1) US20050025658A1 (de)
EP (1) EP1507016B1 (de)
JP (1) JP3918787B2 (de)
KR (1) KR100615465B1 (de)
CN (1) CN1306056C (de)
DE (1) DE602004007730T2 (de)
TW (1) TWI247815B (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2322680A4 (de) * 2008-08-06 2015-07-29 Posco Umweltfreundlicher pb-freier automatenstahl und herstellungsverfahren dafür
EA025921B1 (ru) * 2013-06-24 2017-02-28 Государственное Научное Учреждение "Объединенный Институт Машиностроения Национальной Академии Наук Беларуси" Низколегированная борсодержащая сталь для цементуемых деталей
EP3382050A4 (de) * 2015-11-27 2019-05-22 Nippon Steel & Sumitomo Metal Corporation Stahl, komponente aus einsatzgehärtetem stahl und herstellungsverfahren für komponente aus einsatzgehärtetem stahl
US11111568B2 (en) 2016-09-30 2021-09-07 Nippon Steel Corporation Steel for cold forging and manufacturing method thereof

Families Citing this family (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006255848A (ja) * 2005-03-18 2006-09-28 Nippon Steel Corp 低炭快削鋼の切削工具及び切削方法
JP2007289979A (ja) * 2006-04-23 2007-11-08 Sanyo Special Steel Co Ltd Ｔｉ添加はだ焼鋼からなる鋳鋼片または鋼塊の製造方法およびその鋳鋼片または鋼塊並びにその鋳鋼片または鋼塊からなるはだ焼鋼鋼材
KR100979058B1 (ko) * 2007-10-17 2010-08-30 주식회사 포스코 피삭성 및 열간압연성이 우수한 환경친화형 무연 쾌삭강
KR100825566B1 (ko) * 2006-12-28 2008-04-25 주식회사 포스코 피삭성 및 열간압연성이 우수한 환경친화형 무연 쾌삭강
WO2008082153A1 (en) * 2006-12-28 2008-07-10 Posco Eco-friendly pb-free free cutting steel with excellent machinability and hot workability
JP4473928B2 (ja) * 2007-04-18 2010-06-02 新日本製鐵株式会社 被削性と衝撃値に優れた熱間加工鋼材
RU2355812C1 (ru) * 2008-02-01 2009-05-20 Юлия Алексеевна Щепочкина Сталь
KR101018091B1 (ko) 2008-07-09 2011-02-25 주식회사 포스코 구성인선이 적고 표면조도가 우수한 무연 쾌삭강 및 그제조방법
KR101027246B1 (ko) 2008-08-06 2011-04-06 주식회사 포스코 절삭성이 우수한 친환경 무연쾌삭강 및 그 제조방법
KR101105084B1 (ko) * 2008-11-04 2012-01-16 주식회사 포스코 피삭성이 우수한 친환경 무연쾌삭강
CN102209798B (zh) * 2009-05-22 2013-10-30 新日铁住金株式会社 切削工具寿命优良的机械结构用钢及其切削方法
KR101289103B1 (ko) 2009-12-14 2013-07-23 주식회사 포스코 절삭성 및 열간압연성이 우수한 무연쾌삭강 선재 및 그 제조방법
PL2772559T3 (pl) * 2011-10-25 2017-05-31 Nippon Steel & Sumitomo Metal Corporation Blacha stalowa cienka
JP6036997B2 (ja) * 2013-04-23 2016-11-30 新日鐵住金株式会社 耐疲労特性に優れたばね鋼及びその製造方法
WO2014175381A1 (ja) * 2013-04-25 2014-10-30 新日鐵住金株式会社 鋼板
CN104911457A (zh) * 2014-03-15 2015-09-16 紫旭盛业（昆山）金属科技有限公司 一种抗高温模具钢
CN103911550A (zh) * 2014-03-24 2014-07-09 北京科技大学 一种热塑性优良的环保型低碳高硫铋易切削钢
CN104696379B (zh) * 2015-02-10 2017-12-19 山东金马工业集团股份有限公司 节叉产品及其制备方法
US10400320B2 (en) 2015-05-15 2019-09-03 Nucor Corporation Lead free steel and method of manufacturing
CN110129516A (zh) * 2019-06-11 2019-08-16 南京钢铁股份有限公司 一种控制低碳高硫易切削钢中硫化物形态的方法
CN110714161B (zh) * 2019-10-17 2020-09-22 中天钢铁集团有限公司 一种汽车用高硫易切削钢及其生产工艺
CN110791709B (zh) * 2019-11-11 2020-12-04 广东韶钢松山股份有限公司 结构钢线材、改善结构钢线材切削性能的方法
TWI747777B (zh) * 2020-03-31 2021-11-21 日商杰富意鋼鐵股份有限公司 易切削鋼及其製造方法
KR102771851B1 (ko) * 2020-03-31 2025-02-21 제이에프이 스틸 가부시키가이샤 쾌삭강 및 그 제조 방법
CN112095051B (zh) * 2020-11-02 2021-02-02 北京科技大学 镁钙碲复合处理的易切削钢及其制备方法和应用

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4604146A (en) * 1980-11-08 1986-08-05 Sumitomo Metal Industries, Ltd. Process for manufacturing high tensile steel wire
EP0903418A1 (de) * 1996-11-25 1999-03-24 Sumitomo Metal Industries, Ltd. Stahl mit hervorragender verarbeitbarkeit und damit hegestelltes bauteil
JP2000160284A (ja) * 1998-11-25 2000-06-13 Sumitomo Metal Ind Ltd 快削鋼
EP1054074A2 (de) * 1999-05-21 2000-11-22 POHANG IRON & STEEL CO., LTD. Wismut und Schwefel enthaltenden zerspanbaren Stahl mit ausgezeichneter Dehnbarkeit bei hohen Temperaturen und Herstellungsverfahren dafür
JP2000336454A (ja) * 1999-05-25 2000-12-05 Pohang Iron & Steel Co Ltd 高温延性に優れたビスマス（Ｂｉ）−硫黄（Ｓ）系快削鋼、及びその製造方法
JP2001294976A (ja) * 2000-04-06 2001-10-26 Natl Inst Of Advanced Industrial Science & Technology Meti 機械的性質の異方性が小さく、熱間加工性に優れた快削鋼
EP1262572A1 (de) * 2001-06-01 2002-12-04 Daido Steel Company Limited Automatenstahl
EP1312689A1 (de) * 2001-11-15 2003-05-21 Sumitomo Metal Industries, Ltd. Stahl verwendbar im Maschinenbau
EP1335035A1 (de) * 2002-02-04 2003-08-13 Sumitomo Metal Industries, Ltd. Automatenstahl mit niedrigem Kohlenstoffgehalt

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2003A (en) * 1841-03-12 Improvement in horizontal windivhlls
JP2810245B2 (ja) * 1991-01-25 1998-10-15 日本鋼管株式会社 プレス成形性および燐酸塩処理性に優れた冷延鋼板およびその製造方法
JPH04247849A (ja) * 1991-01-25 1992-09-03 Nkk Corp プレス成形性および燐酸塩処理性に優れた冷延鋼板およびその製造方法
TW567233B (en) * 2001-03-05 2003-12-21 Kiyohito Ishida Free-cutting tool steel
JP2003119545A (ja) * 2001-10-15 2003-04-23 Aichi Steel Works Ltd 被削性に優れた低延性非調質鋼
JP3929029B2 (ja) * 2002-03-12 2007-06-13 三菱製鋼株式会社 含硫黄快削鋼
DE60318745T2 (de) * 2002-11-15 2009-01-15 Nippon Steel Corp. Stahl mit hervorragender zerspanbarkeit und herstellungsverfahren dafür

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4604146A (en) * 1980-11-08 1986-08-05 Sumitomo Metal Industries, Ltd. Process for manufacturing high tensile steel wire
EP0903418A1 (de) * 1996-11-25 1999-03-24 Sumitomo Metal Industries, Ltd. Stahl mit hervorragender verarbeitbarkeit und damit hegestelltes bauteil
JP2000160284A (ja) * 1998-11-25 2000-06-13 Sumitomo Metal Ind Ltd 快削鋼
EP1054074A2 (de) * 1999-05-21 2000-11-22 POHANG IRON & STEEL CO., LTD. Wismut und Schwefel enthaltenden zerspanbaren Stahl mit ausgezeichneter Dehnbarkeit bei hohen Temperaturen und Herstellungsverfahren dafür
JP2000336454A (ja) * 1999-05-25 2000-12-05 Pohang Iron & Steel Co Ltd 高温延性に優れたビスマス（Ｂｉ）−硫黄（Ｓ）系快削鋼、及びその製造方法
JP2001294976A (ja) * 2000-04-06 2001-10-26 Natl Inst Of Advanced Industrial Science & Technology Meti 機械的性質の異方性が小さく、熱間加工性に優れた快削鋼
EP1262572A1 (de) * 2001-06-01 2002-12-04 Daido Steel Company Limited Automatenstahl
EP1312689A1 (de) * 2001-11-15 2003-05-21 Sumitomo Metal Industries, Ltd. Stahl verwendbar im Maschinenbau
EP1335035A1 (de) * 2002-02-04 2003-08-13 Sumitomo Metal Industries, Ltd. Automatenstahl mit niedrigem Kohlenstoffgehalt

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 06 30 June 1997 (1997-06-30) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 09 13 October 2000 (2000-10-13) *
PATENT ABSTRACTS OF JAPAN vol. 2000, no. 15 6 April 2001 (2001-04-06) *
PATENT ABSTRACTS OF JAPAN vol. 2002, no. 02 2 April 2002 (2002-04-02) *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2322680A4 (de) * 2008-08-06 2015-07-29 Posco Umweltfreundlicher pb-freier automatenstahl und herstellungsverfahren dafür
EA025921B1 (ru) * 2013-06-24 2017-02-28 Государственное Научное Учреждение "Объединенный Институт Машиностроения Национальной Академии Наук Беларуси" Низколегированная борсодержащая сталь для цементуемых деталей
EP3382050A4 (de) * 2015-11-27 2019-05-22 Nippon Steel & Sumitomo Metal Corporation Stahl, komponente aus einsatzgehärtetem stahl und herstellungsverfahren für komponente aus einsatzgehärtetem stahl
US10597765B2 (en) 2015-11-27 2020-03-24 Nippon Steel Corporation Steel, carburized steel component, and method for manufacturing carburized steel component
US11111568B2 (en) 2016-09-30 2021-09-07 Nippon Steel Corporation Steel for cold forging and manufacturing method thereof

Also Published As

Publication number Publication date
TW200506071A (en) 2005-02-16
JP2005054227A (ja) 2005-03-03
EP1507016B1 (de) 2007-07-25
CN1306056C (zh) 2007-03-21
DE602004007730T2 (de) 2008-04-30
US20050025658A1 (en) 2005-02-03
TWI247815B (en) 2006-01-21
KR100615465B1 (ko) 2006-08-25
DE602004007730D1 (de) 2007-09-06
JP3918787B2 (ja) 2007-05-23
CN1580312A (zh) 2005-02-16
KR20050016017A (ko) 2005-02-21

Similar Documents

Publication Publication Date Title
EP1507016B1 (de) Niedrig gekohlter Automatenstahl.
KR100513992B1 (ko) 저탄소 쾌삭강
US20130294961A1 (en) Lead free free-cutting steel and its use
US9062360B2 (en) Steel for machine structural use
EP3382051A1 (de) Stahl, komponente aus einsatzgehärtetem stahl und herstellungsverfahren für komponente aus einsatzgehärtetem stahl
JP2000034538A (ja) 旋削加工性に優れた機械構造用鋼
JP2636816B2 (ja) 合金工具鋼
JP7560714B2 (ja) 機械構造用棒鋼
JP3416869B2 (ja) 被削性に優れた低延性非調質鋼材
JPH0555585B2 (de)
JP4502929B2 (ja) 転動疲労特性および結晶粒粗大化防止特性に優れた肌焼用鋼
JP3912308B2 (ja) 機械構造用鋼
JP5323369B2 (ja) 被削性と結晶粒粗大化防止特性に優れた肌焼鋼
EP1471159A1 (de) Nichtraffinierter stahl vom bainit-typ für die nitridierung, herstellungsverfahren dafür und nitridiertes produkt
JP3395642B2 (ja) 耐粗粒化肌焼鋼材並びに強度と靭性に優れた表面硬化部品及びその製造方法
JP3256184B2 (ja) 超快削鋼棒線材及び部品の製造方法並びにそれらによる超快削鋼棒線材及び部品
JP2000129393A (ja) 被削性に優れたマルテンサイト・ベイナイト型非調質鋼材及びその製造方法
JP3489655B2 (ja) 高強度高靭性快削非調質鋼材
JP3416868B2 (ja) 被削性に優れた高強度・低延性非調質鋼材
JP2000282184A (ja) 被削性と耐食性に優れた高周波焼入れ用高硬度鋼
JP2004315840A (ja) 被削性に優れた冷間工具鋼及びその製造方法
JPH11302778A (ja) 被削性に優れた低延性非調質鋼材
WO2026034120A1 (ja) 快削鋼引抜材及びその製造方法
JPH0610091A (ja) 被削性の優れた高強度熱間鍛造非調質品
JPH06158220A (ja) 被削性の優れた高強度調質品

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20040813

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

AKX Designation fees paid

Designated state(s): DE FR GB

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 602004007730

Country of ref document: DE

Date of ref document: 20070906

Kind code of ref document: P

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20080428

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20090710

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20090723

Year of fee payment: 6

Ref country code: GB

Payment date: 20090729

Year of fee payment: 6

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20100730

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20110331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20110201

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602004007730

Country of ref document: DE

Effective date: 20110201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100802

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20100730