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
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/22—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for drills; for milling cutters; for machine cutting tools
• • 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
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper

Definitions

• the present invention relates to a high corrosion-resistant, high-strength and non-magnetic stainless steel, a high-strength, high corrosion-resistant and non-magnetic stainless steel product and a method for producing the same. More particularly, the invention relates to a technique for producing a non-magnetic stainless steel which is capable of blocking the influence of earth magnetism and is particularly suitable for the use in oil well excavation, without impairing its characteristics (high corrosion resistance and high strength).
• a position for example, direction and inclination
• a measuring instrument is mounted in a drill collar in the vicinity of a bit.
• the drill collar and the like are required to be made of a non-magnetic steel, in order to block the influence of earth magnetism.
• Patent document 1 JP-A-53-117618 discloses a high-strength austenitic stainless steel containing C: 0.15% or less, Si: 0.1 to 2.0%, Mn: 7.0 to 18%, Ni: 0.50 to 6.0%, Cr: 15.0 to less than 21.0%, Mo: 0.5 to 4.0%, N: 0.20 to 0.60% and the balance composed of Fe and impurities, which is for the use to a body of rotation of a centrifuge or the like.
• Patent document 2 JP-A-59-104455 discloses a ultra-low temperature high-strength steel excellent in rust resistance, which contains C: 0.01 to 0.20 wt%, Si: 0.05 to 1.5 wt%, Mn: 16 to 27 wt%, Cr: 10 to 20 wt%, Cu: 0.1 to 4 wt%, N: 0.10 to 0.50 wt%, Al: 0.003 to 0.20 wt% and the balance composed of Fe and unavoidable impurities, which is for the use to a holding material of a superconductive electromagnet or a superconductor, or the like.
• Patent document 3 JP-A-59-205452 discloses a high-strength member for an instrument loaded on an undersea research ship, which contains C: 0.15% or less, Si: 0.1 to 2.0%, Mn: 7.0 to 18.0%, Ni: 0.50 to 6.0%, Cr: 15.0 to 26.0%, Mo: 0.5 to 4.0%, N: 0.2 to 0.6% and the balance substantially composed of Fe, and is subjected to hot working at a rolling reduction of 50% or more, wherein the finishing temperature of the hot working is from 800 to 1,000°C.
• Patent document 4 JP-A-61-143563 discloses a rust-resistant, ultra-low temperature high manganese high-strength steel containing C: 0.20% or less, Si: 0.05 to 2.5%, Mn: 16 to 35%, Cr: 10 to 20%, Ni: 0.1 to 8.0%, N: 0.10 to 0.50%, Al: 0.001 to 0.20%, S: 0.003% or less and the balance composed of Fe and unavoidable impurities, which is for the use to a holding material of a superconductive electromagnet or a superconductor, or the like.
• Patent document 5 JP-A-61-170545 discloses an ultra-low temperature high manganese steel excellent in rust resistance, which contains C: 0.20% or less, Si: 0.05 to 2.5%, Mn: 9 to 35%, Cr: 10 to 20%, Ni: 0.1 to 8.0%, N: 0.001 to 0.50%, Al: 0.001 to 0.20%, Ca: 0.001 to 0.020% and the balance composed of Fe and unavoidable impurities, for the use to a structure used in a fusion experimental reactor using a superconductive electromagnet, or the like.
• Patent document 6 JP-A-61-238943 discloses a high-strength non-magnetic stainless steel excellent in rust resistance, which contains C: 0.01 to 0.15 wt%, Si: 0.05 to 0.60 wt%, Mn: 16 to 25 wt%, S: 0.010 wt% or less, Ni: 4.0 wt% or less, Cr: 14 to 20 wt%, N: 0.3 to 0.6 wt%, O: 0.01 wt% or less, Al: 0.001 to 0.20 wt% and the balance composed of Fe and unavoidable impurities, and contains non-metallic inclusions in an area ratio of 0.10% or less, which is for the use to a precision equipment part (a micromotor shaft, a magnetic tape guide, a shaft or the like) that is required to avoid magnetism.
• a precision equipment part a micromotor shaft, a magnetic tape guide, a shaft or the like
• Patent document 7 JP-A-2004-052097 discloses an interdental brush wire containing, by mass, C: 0.07% or less, Si: 0.6% or less, Mn: 13 to 17%, Ni: 2.0 to 5.0%, Cr: 16.0 to 20.0%, Mo: 0.4 to 2.0%, N: 0.3 to 0.60% and Cu: 0.3 to 1.0%, which is for the use to the interdental brush wire.
• Patent document 8 JP-A-2004-156086 discloses a non-magnetic stainless steel containing C: 0.06% or less, Si: 0.40% or less, Mn: 15.5 to 17%, P: 0.040% or less, S: 0.010% or less, Cu: 0.35 to 2.00%, Ni: 2.50 to 4.00%, Cr: 17.0 to 21.0%, Mo+W: 0.5 to 1.5%, N: 0.42 to 0.65%, O: 0.01% or less, sol-Al: 0.05% or less, B: 0.001 to 0.010% and the balance substantially composed of Fe, which is for the use to a drill collar for oil well excavation.
• the recent oil well excavation region is versatile, and further high-corrosion resistant and high-strength stainless steels based on the assumption of non-magnetism have been demanded by the industrial world.
• the various types of steels described in the above-mentioned patent documents 1 to 8 have many problems to be solved.
• the high-strength austenitic stainless steel of patent document 1 and the high-strength member for an instrument loaded on an undersea research ship of patent document 3 have a concern that workability and corrosion resistance are deteriorated by crystallization of coarse carbides due to their excessive C content.
• the ultra-low temperature high-strength steel of patent document 2 and the rust-resistant, ultra-low temperature high manganese high-strength steel of patent document 4 have a concern that the required characteristics of non-magnetism, high strength and corrosion resistance are not satisfied due to their small N content.
• the ultra-low temperature high-strength steel of patent document 2 has a further concern that corrosion resistance is deteriorated due to its excessive Mn content.
• the ultra-low temperature high manganese steel of patent document 5 has a concern that the required characteristics of non-magnetism, high strength and corrosion resistance are not satisfied, because the Cr content is rather small with respect to the Mn content, and the N content is also rather small.
• the Ni and N contents are rather small.
• Mn and Ni contents are excessively small.
• the non-magnetic stainless steel of patent document 8 the Ni and Mo contents are excessively small. Therefore, these alloys have a concern that the required characteristics of non-magnetism, high strength and corrosion resistance are not satisfied. As described above, even according to patent documents 1 to 8, no stainless steel satisfying the required characteristics has been obtained.
• the invention has been made in view of the above circumstances, and an object of the invention is to provide a high corrosion-resistant, high-strength and non-magnetic stainless steel having high corrosion resistance, high strength and non-magnetism; a high corrosion-resistant, high-strength and non-magnetic stainless steel product and a method for producing the same.
• an object of the invention is to provide a high corrosion-resistant, high-strength and non-magnetic stainless steel which blocks the influence of earth magnetism at the time of oil well evacuation, and not only can be applied to oil well excavation products covering a wide range of regions, but also is suitable as raw materials for various parts (various spring products, VTR guide pins and motor shafts); a high corrosion-resistant, high-strength and non-magnetic stainless steel product and a method for producing the same.
• the present inventors have made intensive studies, centering on application of Cr and Mo as corrosion resistance-improving elements, for realizing high corrosion resistance.
• the inventors have encountered a problem that "non-magnetism which is capable of blocking the influence of earth magnetism" required for a drill collar and the like of oil well evacuation and the like cannot be achieved, because an increase in Cr content and Mo content causes magnetization.
• the inventors have made further intensive studies. As a result, it has been found that when a composition balance is adjusted by making use of N and Ni, a stable non-magnetic austenite single-phase structure is obtained, even in the case where Cr and Mo are used to obtain high corrosion resistance.
• the invention has been made based on such a finding.
• the present invention provides a high corrosion-resistant, high-strength and non-magnetic stainless steel containing: C: 0.01% to 0.05% by mass, Si: 0.05% to 0.50% by mass, Mn: more than 16.0% by mass but 19.0% by mass or less, P: 0.040% by mass or less, S: 0.010% by mass or less, Cu: 0.50% to 0.80% by mass, Ni: 3.5% to 5.0% by mass, Cr: 17.0% to 21.0% by mass, Mo: 1.80% to 3.50% by mass, B: 0.0010% to 0.0050% by mass, O: 0.010% by mass or less, and N: 0.45% to 0.65% by mass, with the balance substantially composed of Fe and unavoidable impurities, the steel satisfying the following equations (1) to (4): Cr + 3.3 ⁇ Mo + 16 ⁇ N ⁇ 30 Cr / C ⁇ 330 Cr / Mn > 1.0 Ni + 3 ⁇ Cu / Cr + Mo > 0.25 wherein [Cr], [Mo], [N], [
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to the present invention may further contains at least one element selected from the group consisting of Ca, Mg and REM in a total content of 0.0001% to 0.0100% by mass.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to the present invention may further contains at least one element selected from the group consisting of Nb, V, Ta and Hf in a total content of 0.1 % to 2.0% by mass.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to the present invention may further contains A1 in a content of 0.001 % to 0.10% by mass.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to the present invention may further contains at least one member selected from the group consisting of W and Co in a total content of 0.1% to 3.0% by mass.
• the present invention further provides a method for producing a high corrosion-resistant, high-strength and non-magnetic stainless steel product, which includes subjecting the steel according to the present invention to working under a temperature condition of 300°C to 900°C at a reduction of area of 15% to 40%.
• the present invention furthermore provides a high corrosion-resistant, high-strength and non-magnetic stainless steel product obtained by subjecting the steel according to the present invention to working under a temperature condition of 300°C to 900°C at a reduction of area of 15% to 40%.
• a high corrosion-resistant, high-strength and non-magnetic stainless steel product obtained by subjecting the steel according to the present invention to working under a temperature condition of 300°C to 900°C at a reduction of area of 15% to 40%.
• the resulting steel product include oil well evacuation products, spring products, VTR guide pins, motor shafts and the like.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel and the high corrosion-resistant, high-strength and non-magnetic stainless steel product according to the invention have the above-mentioned component composition and satisfies the above-mentioned equations (1) to (4), so that they have high corrosion resistance, high strength and non-magnetism. Accordingly, they has effects of being able to block the influence of earth magnetism at the time of oil well evacuation to be applied to oil well excavation products covering a wide range of regions, and moreover, being-suitable as raw materials for various parts (various spring products, VTR guide pins and motor shafts).
• the resulting steel product can exhibit the same effects as described above.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to this embodiment contains the following essential elements and selective elements and the balance substantially composed of Fe and unavoidable impurities, and satisfies relationship defined by equations (1) to (4) described later.
• equations (1) to (4) described later.
• all the percentages defined by mass are the same as those defined by weight, respectively.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to this embodiment contains C, Si, Mn, Cu, Ni, Cr, Mo, B and N as essential elements, and the balance is substantially composed of Fe and unavoidable impurities.
• the unavoidable impurities as mentioned herein include, for example, P, S and O.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to this embodiment may further contain the following selective elements, that is to say, at least one element selected from the group consisting of Ca, Mg and REM; the group consisting ofNb, V, Ta and Hf; Al; and the group consisting of W and Co.
• At least one element selected from the group consisting of Ca, Mg and REM in a total content of 0.0001% to 0.0100% by mass Ca, Mg and REM are selective elements, and elements effective for improving hot workability of the steel. Accordingly, they may be added in a total content of 0.0001 % by mass or less. However, excessive addition of these elements results in saturation of the effect, and conversely decreases hot workability. Accordingly, 0.0100% by mass is specified as the upper limit of the total content thereof. The total content thereof is more preferably 0.0050% by mass or less.
• REM means one containing Ce, La or an alloy thereof.
• Co is a selective element, and effective for obtaining an austenite single-phase structure to achieve high strength by solid solution strengthening. Accordingly, Co may be added as needed. However, excessive addition of Co causes a substantial increase in cost, so that 3.0% by mass is specified as the upper limit of the content of Co.
• the content of Co is more preferably 1.5% by mass or less.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to this embodiment satisfies the following equations (1) to (4):
• the minimal amount thereof present in the steel is the smallest non-zero amount used in the inventive steels as summarized in Tables 1 and 2.
• the maximum amount thereof present in the steel is the maximum amount used in the inventive steels as summarized in Tables 1 and 2.
• the high-corrosion resistant, high strength and non-magnetic stainless steel according to this embodiment is obtained by
• the materials under test were processed to various test specimens.
• the tensile strength, the 0.2% yield strength and the elongation (%) were determined by preparing a JIS No. 4 test specimen from each of the materials under test, and measuring the breaking stress at the time when the tensile load is applied to a leading edge of the specimen in accordance with JIS Z 2241.
• the magnetic permeability was determined by performing measurement of the magnetic permeability according to the VSM method, taking the external magnetic field as 2,000 Oe.
• the corrosion resistance was evaluated by the 6% ferric chloride test (JIS G 0578) and the 10% oxalic acid etching test (JIS G 0571). The test results thereof are shown together in Tables 3 and 4.
• Inventive Steels 1 to 26 satisfied the required characteristics for all of strength (tensile strength ⁇ 1050 MPa, 0.2% yield strength ⁇ 968 MPa), workability (elongation ⁇ 25), non-magnetism (magnetic permeability ⁇ 1.010) and corrosion resistance (ferric chloride corrosion ⁇ 0.5, 10% oxalic acid etching: step).
• Inventive Steels 1 to 26 contained the components defined in Tables 1 and 2 in predetermined amounts, and satisfied equations (1) to (4) defined in Tables 1 and 2. It is therefore conceivable that corrosion resistance, strength and non-magnetism could be achieved at the same time.
• Inventive Steels 1 to 26 block the influence of earth magnetism at the time of oil well evacuation, and not only can be applied to oil well excavation products covering a wide range of regions, but also are suitable as raw materials for various parts (various spring products, VTR guide pins and motor shafts).
• Comparative Steels 1 to 10 did not satisfy the required characteristic for any one of strength (tensile strength ⁇ 1050 MPa, 0.2% yield strength ⁇ 968 MPa), workability (elongation ⁇ 25), non-magnetism (magnetic permeability ⁇ 1.010) and corrosion resistance (ferric chloride corrosion ⁇ 0.5, 10% oxalic acid etching: step). The reason for this is considered to be that Comparative Steels 1 to 10 did not contain the components defined in Table 2 in predetermined amounts, or did not satisfy any one of equations (1) to (4).
• Comparative Steel 1 did not satisfy equation 1 because of its small Mo content, and further did not satisfy equation 2 because of its excessive C content. Corrosion resistance is therefore considered to be impaired even when the Mn content is small.
• Comparative Steel 1 did not satisfy equation 4, it satisfied the required characteristic for magnetic permeability.
• Comparative Steel 2 contained Cr essential for securing corrosion resistance in a predetermined amount, but did not satisfy equation 1 because of its small Mo and N contents. Corrosion resistance is therefore considered to be impaired. Further, high magnetic permeability of Comparative Steel 2 is considered to be caused by the small N content.
• Comparative Steel 3 contained Cr essential for securing corrosion resistance in a predetermined amount, but did not satisfy equation 1 because of its small Mo and N contents, and did not satisfy equation 2 because of its excessive C content. Corrosion resistance is therefore considered to be impaired. Comparative Steels 4 and 5 did not satisfy equations (1) and (3) because of their excessively small Mo content, excessive Mn content and rather small Cr content. Corrosion resistance is therefore considered to be impaired. Comparative Steel 6 did not satisfy equation (4) because of its excessively small Cu content. Corrosion resistance is therefore considered to be impaired.
• Comparative Steel 7 satisfied equations (1) to (4), and satisfied the required characteristics of high corrosion resistance, non-magnetism and high strength, although the Cu, Ni and Mo contents were outside the predetermined ranges. However, it was revealed that Comparative Steel 7 was decreased in elongation to cause difficulty in working, which was unsuitable for actual production, because of its low working temperature. Comparative Steel 8 did not satisfy equation (1), because of its excessively small Cu and Mo contents. Corrosion resistance is therefore considered to be impaired. Further, in Comparative Steel 8, the working temperature was increased to 950°C. However, it was confirmed that an increase in working temperature was not so much effective for an increase in strength.
• Comparative Steels 9 and 10 did not satisfied equation (1) because of its excessively small Mo content, did not satisfy equation (3) in relation to the balance of the components, and was excessively small in Cu content. Corrosion resistance is therefore considered to be impaired. Further, both of these were high in magnetic permeability. Incidentally, in Comparative Steel 9, the reduction of area was as low as 10%, although the working temperature was low. It is therefore conceivable that deterioration of workability did not occur by high elongation and work hardening. On the other hand, in Comparative Steel 10, the working temperature was low, and moreover, the reduction of area was as high as 50%. It was therefore revealed that Comparative Steel 10 was increased in strength by work hardening, but decreased in elongation to cause difficulty in working, which was unsuitable for actual production.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel, the high corrosion-resistant, high-strength and non-magnetic stainless steel product and the method for producing the same, according to the invention has the predetermined component composition, and the predetermined mutual relationship of the components is adjusted. Accordingly, the industrial use value thereof is high for steel product manufacturers.
• the high corrosion-resistant, high-strength and non-magnetic stainless steel according to the invention is expected to be applied to oil well excavation products and steel products such as spring, shaft, bolt and screw products.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Electromagnetism (AREA)
• Manufacturing & Machinery (AREA)
• Heat Treatment Of Steel (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=42321059

Family Applications (1)

Country Status (4)

Cited By (3)

Families Citing this family (14)

Citations (12)

Family Cites Families (9)

• 2010
  • 2010-01-27 JP JP2010015591A patent/JP5526809B2/ja active Active
  • 2010-04-23 US US12/766,390 patent/US20100272593A1/en not_active Abandoned
  • 2010-04-26 CN CN201010159146.2A patent/CN101921970B/zh active Active
  • 2010-04-27 EP EP10004443.7A patent/EP2248919B1/fr active Active

Patent Citations (12)

Also Published As

Similar Documents

Legal Events