JPH07173573A - Free-cutting steel excellent in machinability by carbide tool and internal quality - Google Patents
Free-cutting steel excellent in machinability by carbide tool and internal qualityInfo
- Publication number
- JPH07173573A JPH07173573A JP31840993A JP31840993A JPH07173573A JP H07173573 A JPH07173573 A JP H07173573A JP 31840993 A JP31840993 A JP 31840993A JP 31840993 A JP31840993 A JP 31840993A JP H07173573 A JPH07173573 A JP H07173573A
- Authority
- JP
- Japan
- Prior art keywords
- steel
- cutting
- machinability
- free
- added
- 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.)
- Pending
Links
- 229910000915 Free machining steel Inorganic materials 0.000 title claims abstract description 45
- 238000005096 rolling process Methods 0.000 claims abstract description 22
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052745 lead Inorganic materials 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 229910052742 iron Inorganic materials 0.000 claims abstract description 9
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 7
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 7
- 229910052797 bismuth Inorganic materials 0.000 claims abstract description 6
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 6
- 229910052714 tellurium Inorganic materials 0.000 claims abstract description 6
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 5
- 229910052738 indium Inorganic materials 0.000 claims abstract description 4
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 4
- 229910052799 carbon Inorganic materials 0.000 claims abstract 2
- 238000005520 cutting process Methods 0.000 claims description 40
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 28
- 238000009749 continuous casting Methods 0.000 claims description 17
- 229910052760 oxygen Inorganic materials 0.000 claims description 8
- 230000001105 regulatory effect Effects 0.000 abstract description 3
- 238000003754 machining Methods 0.000 abstract description 2
- 229910052789 astatine Inorganic materials 0.000 abstract 1
- 229910000831 Steel Inorganic materials 0.000 description 162
- 239000010959 steel Substances 0.000 description 162
- 230000000694 effects Effects 0.000 description 24
- 239000000463 material Substances 0.000 description 13
- 239000000203 mixture Substances 0.000 description 10
- 238000001816 cooling Methods 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 229920006395 saturated elastomer Polymers 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 4
- 239000002131 composite material Substances 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000005498 polishing Methods 0.000 description 4
- 238000005204 segregation Methods 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000012937 correction Methods 0.000 description 3
- 229910000997 High-speed steel Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000010622 cold drawing Methods 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000011056 performance test Methods 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000003832 thermite Substances 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、超硬工具による被切削
用快削鋼に関し、詳しくは、超硬工具、超硬コーテイン
グ工具、サーメツト工具及びセラミツク工具等（以下、
これらを単に超硬工具と総称する。）の超硬工具による
被切削性と内部品質とにすぐれる連続鋳造による快削鋼
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free-cutting steel for cutting with a cemented carbide tool, and more specifically, a cemented carbide tool, a cemented carbide coating tool, a thermet tool, a ceramic tool, etc.
These are simply referred to as cemented carbide tools. ) Relates to free-cutting steel by continuous casting, which is excellent in machinability with carbide tools and internal quality.
【０００２】[0002]
【従来の技術】一般に、ＡＩＳＩ １１系、１２系等の
Ｓ含有快削鋼は、圧延後、引抜き加工して、磨棒鋼とし
て自動盤切削用に供される。このような従来の快削鋼
は、上記した自動盤切削をはじめとして、高速度鋼工具
による被切削性を良好にするために、鋼中へのＳｉ、Ａ
ｌ等の脱酸力の強い元素の添加を極力抑えて、鋼中のＭ
ｎＳの形状を丸く、且つ、大きくしており、かかる快削
鋼は、高速度工具の寿命と鋼の切削仕上面にすぐれてい
る。このように、従来、快削鋼の被切削性を高めるに
は、介在物を大きくすることが有効であることが知られ
ている。2. Description of the Related Art In general, S-containing free-cutting steels such as AISI 11 series and 12 series are rolled and then drawn to be used as a bar steel for automatic lathe cutting. Such conventional free-cutting steels include Si and A in steel in order to improve the machinability by a high-speed steel tool, including the automatic lathe cutting described above.
The addition of elements with strong deoxidizing power such as l is suppressed as much as possible, and M in steel
The shape of nS is round and large, and such free-cutting steel is excellent in the life of high-speed tools and the cutting surface finish of steel. As described above, it has been conventionally known that increasing the size of inclusions is effective for improving the machinability of free-cutting steel.
【０００３】しかし、最近の数値制御旋盤の普及によつ
て、１１系、１２系快削鋼でも、前記超硬工具による高
速切削加工が増えつつあることから、本発明者らは、既
に、特公平５−５１６５５号公報に記載されているよう
に、超硬工具による切削加工において被切削性にすぐれ
る快削鋼を開発している。一方において、油圧・空圧機
械部品に適用した場合に、油や空気漏れの原因となる大
きい介在物のない快削鋼の出現が待たれている。このよ
うな要望に対しては、既に、例えば、電気製鋼、第６０
巻第３号第２８８〜２９１頁に「クリーン超快削鋼」な
るものも提案されている。However, with the recent widespread use of numerically controlled lathes, high-speed cutting with the above-mentioned cemented carbide tools is increasing even for 11-series and 12-series free-cutting steels. As described in Japanese Patent Publication No. 5-51655, a free-cutting steel having excellent machinability in cutting with a cemented carbide tool is being developed. On the other hand, the appearance of free-cutting steel without large inclusions that cause oil or air leakage when applied to hydraulic / pneumatic mechanical parts is awaited. For such a request, for example, electric steelmaking, No. 60
Vol. 3, No. 3, pp. 288-291, a "clean ultra-free cutting steel" is also proposed.
【０００４】しかし、このように、近年に開発された快
削鋼によつても、最近のますます高まる高速切削加工
や、機械部品の高精度化、高密度化に対処するには十分
とはいえず、一層、被切削性にすぐれると共に、内部品
質にもすぐれる快削鋼が強く要望されるに至つている。However, as described above, even the free-cutting steels developed in recent years are not enough to cope with the recent increasing high-speed cutting, high precision and high density of machine parts. Not to mention, there has been a strong demand for free-cutting steel that excels in machinability and internal quality.
【０００５】[0005]
【発明が解決しようとする課題】従つて、本発明は、特
に、超硬工具による切削加工において、被切削性にすぐ
れると共に、内部品質にもすぐれる連続鋳造による快削
鋼を提供することを目的とする。SUMMARY OF THE INVENTION Accordingly, the present invention provides a free-cutting steel by continuous casting which is excellent in machinability and is excellent in internal quality, especially in cutting with a cemented carbide tool. With the goal.
【０００６】[0006]
【課題を解決するための手段】本発明による超硬工具に
よる被切削性と内部品質のすぐれる連続鋳造による削鋼
の第１は、重量％で Ｃ 0.０１〜0.２０％、Ｓｉ 0.１０〜0.６０％、Ｍ
ｎ 0.５〜２％、Ｐ 0.００５〜0.１２％、Ｓ 0.
１５〜0.４０％、Ｏ 0.００１〜0.０１０％、及びＮ
0.００３〜0.０３％を含有し、残部鉄及び不可避的
不純物よりなり、圧延方向に存在する硫化物介在物の平
均面積が４０μｍ2 以下であることを特徴とする。The first cutting steel by continuous casting which has excellent machinability and internal quality by the cemented carbide tool according to the present invention is C 0.01 to 0.20% by weight, and Si 0. .10 to 0.60%, M
n 0.5-2%, P 0.005-0.12%, S 0.
15-0.40%, O 0.001-0.010%, and N
It is characterized in that it contains 0.003 to 0.03%, the balance is iron and unavoidable impurities, and the average area of sulfide inclusions existing in the rolling direction is 40 μm 2 or less.
【０００７】本発明による超硬工具による被切削性と内
部品質のすぐれる連続鋳造による快削鋼の第２は、重量
％で (a) Ｃ 0.０１〜0.２０％、Ｓｉ 0.１０〜0.６０
％、Ｍｎ 0.５〜２％、Ｐ 0.００５〜0.１２％、Ｓ
0.１５〜0.４０％、Ｏ 0.００１〜0.０１０％、
及びＮ 0.００３〜0.０３％を含有し、更に、(b) Ａ
ｌ 0.００５〜0.０３％、Ｐｂ 0.４％以下、Ｂｉ 0.
４％以下、Ｔｅ 0.１％以下、Ｉｎ 0.２％以下、Ｃａ
0.０００５〜0.０１％、及びＺｒ 0.０１〜0.９％よ
りなる群から選ばれる少なくとも１種を含有し、残部鉄
及び不可避的不純物よりなり、圧延方向に存在する硫化
物介在物の平均面積が４０μｍ2 以下であることを特徴
とする。The second free-cutting steel by continuous casting, which has excellent machinability and internal quality by the cemented carbide tool according to the present invention, is (a) C 0.01-0.20%, Si 0.10% by weight. ~ 0.60
%, Mn 0.5-2%, P 0.005-0.12%, S
0.15 to 0.40%, O 0.001 to 0.010%,
And N 0.003 to 0.03%, and (b) A
l 0.005 to 0.03%, Pb 0.4% or less, Bi 0.0.
4% or less, Te 0.1% or less, In 0.2% or less, Ca
Sulfide inclusions containing at least one selected from the group consisting of 0.0005 to 0.01% and Zr 0.01 to 0.9%, the balance being iron and inevitable impurities, and existing in the rolling direction. Is less than 40 μm 2 in average area.
【０００８】即ち、本発明によれば、鋼にＳｉを添加
し、鋼中の酸素を抑制することによつて、１００μｍ以
上の酸化物介在物や硫化物介在物や、或いはそれらの複
合介在物を減少させると共に、延性を有し、また、超硬
工具と反応し難い硫化物介在物を生成させることによつ
て、超硬工具による切削における工具寿命を大幅に向上
させ、更に、連続鋳造法によつて溶鋼の冷却速度を制御
し、介在物を微細化させる。本発明によれば、このよう
にして、鋼における元素と製造条件の最適化を図つて、
介在物を微細化させるので、介在物は、分塊や圧延後に
一層微細化し、かくして、超硬工具による被切削性と内
部品質とが従来に比べて、一層改善された快削鋼を得る
ことができる。That is, according to the present invention, by adding Si to steel to suppress oxygen in the steel, oxide inclusions or sulfide inclusions of 100 μm or more, or composite inclusions thereof are provided. And the ductility of the cemented carbide, and the formation of sulfide inclusions that are difficult to react with the cemented carbide tool significantly improves the tool life in cutting with the cemented carbide tool. This controls the cooling rate of the molten steel to refine the inclusions. According to the present invention, in this way, by optimizing the elements and manufacturing conditions in steel,
Since the inclusions are made finer, the inclusions are made finer after slabbing and rolling, thus obtaining a free-cutting steel in which the machinability by a cemented carbide tool and the internal quality are further improved compared with conventional ones. You can
【０００９】先ず、本発明鋼において、必須の化学成分
の限定理由について説明する。Ｃは、過多に添加すると
きは、工具寿命を劣化させるので、Ｃ添加量の上限は0.
２０％とする。Ｓｉは、本発明鋼の超硬工具による被切
削性と内部品質の改善のために必須の元素であつて、こ
の目的を達成するためには、少なくとも0.１０％を添加
することが必要である。しかし、過多に添加するとき
は、鋼が硬さを増して、工具寿命を劣化させるので、添
加量の上限を0.６０％とする。First, the reasons for limiting the essential chemical components in the steel of the present invention will be explained. When C is added excessively, the tool life is deteriorated, so the upper limit of the amount of C added is 0.
20%. Si is an essential element for improving the machinability and internal quality of the steel of the present invention with a cemented carbide tool, and in order to achieve this object, it is necessary to add at least 0.10%. is there. However, if too much is added, the hardness of the steel increases and the tool life deteriorates, so the upper limit of the addition is set to 0.60%.
【００１０】Ｍｎは、ＭｎＳを生成させ、ＦｅＳの生成
を抑制するために添加される。この効果を有効に得るた
めには、0.５０〜２％の範囲で添加することが必要であ
る。Ｐは、鋼の切削仕上面を改善するために、0.００５
〜0.１２％の範囲で添加される。Ｓは、本発明におい
て、鋼の被切削性を改善する効果を有し、この効果を有
効に発現させるためには、少なくとも0.１５％を添加す
ることが必要であり、これよりも少ないときは、被切削
性の改善効果に乏しい。しかし、過多に添加するとき
は、鋼の機械的性質を著しく劣化させくので、添加量の
上限は0.４０％とする。Mn is added to produce MnS and suppress the production of FeS. In order to effectively obtain this effect, it is necessary to add it in the range of 0.50 to 2%. P is 0.005 to improve the cutting finish of steel.
It is added in the range of 0.12%. In the present invention, S has the effect of improving the machinability of steel, and it is necessary to add at least 0.15% in order to effectively exhibit this effect. Has a poor effect of improving the machinability. However, if too much is added, the mechanical properties of the steel will be significantly deteriorated, so the upper limit of the amount added is 0.40%.
【００１１】Ｏは、過多に含有するときは、大きい酸化
物介在物が生成して、かかる鋼より製造される機械部品
の内部品質を劣化させる一方、超硬工具による切削に際
して、工具寿命を改善し、更に、内部品質を改善する硫
化物介在物が生成しないので、本発明においては、その
含有量の上限を0.０１０％とする。このように、Ｏの含
有量は、少ない方がよいが、しかし、含有量を極端に低
減することは、そのために特別な処理を必要とするうえ
に、低減することによる上記効果も飽和するので、含有
量の下限を0.００１％とする。When O is contained in an excessive amount, large oxide inclusions are generated, which deteriorates the internal quality of machine parts produced from such steel, while improving the tool life when cutting with a cemented carbide tool. Moreover, since no sulfide inclusions that improve the internal quality are generated, the upper limit of the content is set to 0.010% in the present invention. As described above, it is preferable that the content of O is small. However, if the content of O is extremely reduced, a special treatment is required for that purpose, and the above effect due to the reduction is saturated. , The lower limit of the content is 0.001%.
【００１２】Ｎは、構成刃先の生成量に影響を与える元
素であつて、切削仕上面粗さに影響を及ぼす。含有量が
0.００３％よりも少ないときは、その効果が少なく、他
方、0.０３％を越えるときは、表面疵が多くなるので、
Ｎ含有量は、0.００３〜0.０３％の範囲とする。本発明
による快削鋼は、上述した元素を必須として含有する
が、更に、下記から選ばれる少なくとも１種の元素を含
むことができる。[0012] N is an element that affects the amount of formation of the constituent cutting edge and affects the roughness of the finished surface. Content is
When it is less than 0.003%, the effect is small. On the other hand, when it is more than 0.03%, the surface defects are large.
The N content is in the range of 0.003 to 0.03%. The free-cutting steel according to the present invention essentially contains the above-mentioned elements, but may further contain at least one element selected from the following.
【００１３】Ａｌは、脱酸剤として、また、本発明鋼の
超硬工具による被切削性の改善と内部品質の向上のため
に用いられる元素であつて、このような効果を有効に発
現させるためには、少なくとも0.００５％を添加するこ
とが必要である。しかし、過多に添加するときは、鋼中
にＡｌ2 Ｏ3 が生成し、却つて被切削性に有害な影響を
与えるので、上限は0.０３％とする。Al is an element used as a deoxidizing agent and for improving the machinability and internal quality of the steel of the present invention by the cemented carbide tool, and effectively exhibits such an effect. In order to do so, it is necessary to add at least 0.005%. However, if too much is added, Al 2 O 3 is produced in the steel and adversely affects the machinability, so the upper limit is made 0.03%.
【００１４】Ｐｂは、鋼の被切削性を向上させる元素で
あって、好ましくは、0.０２％以上を添加する。Ｐｂ
は、その添加量が多い程、鋼の被切削性がよくなるが、
反面、Ｐｂの偏析度が大きくなるので、上限を0.４％と
する。Ｂｉも、鋼の被切削性を向上させる元素であっ
て、好ましくは、0.０２％以上を添加する。Ｂｉも、そ
の添加量が多い程、鋼の被切削性がよくなるが、反面、
Ｂｉの偏析度が大きくなるので、上限を0.４％とする。Pb is an element that improves the machinability of steel, and is preferably added in an amount of 0.02% or more. Pb
The higher the amount added, the better the machinability of steel,
On the other hand, the segregation degree of Pb increases, so the upper limit is made 0.4%. Bi is also an element that improves the machinability of steel, and is preferably added in an amount of 0.02% or more. As for Bi, the more the amount of Bi added, the better the machinability of the steel, but on the other hand,
Since the degree of segregation of Bi becomes large, the upper limit is made 0.4%.
【００１５】Ｔｅも、鋼の被切削性を向上させる元素で
あって、好ましくは、0.０１％以上を添加する。この元
素も、その添加量が多い程、鋼の被切削性がよくなる
が、反面、熱間脆性を大きくして、表面疵を多くするの
で、上限を0.１％とする。Ｉｎも、鋼の被切削性を向上
させる元素であって、好ましくは、0.０１％以上を添加
する。この元素も、その添加量が多い程、鋼の被切削性
がよくなるが、しかし、この元素は希少金属であり、高
価であつて、過多に添加することは、経済性の点からも
好ましくない。従つて、本発明においては、添加量を0.
２％以下とする。Te is also an element that improves the machinability of steel, and is preferably added in an amount of 0.01% or more. The higher the amount of addition of this element, the better the machinability of the steel, but on the other hand, the hot brittleness increases and the surface defects increase, so the upper limit is made 0.1%. In is also an element that improves the machinability of steel, and is preferably added in an amount of 0.01% or more. The higher the amount of this element added, the better the machinability of the steel, but this element is a rare metal, is expensive, and it is not preferable to add too much from the economical point of view. . Therefore, in the present invention, the addition amount is 0.
2% or less.
【００１６】Ｃａは、超硬工具寿命を改善する元素であ
つて、この効果を有効に得るためには、少なくとも0.０
００５％の添加が必要である。しかし、過多に添加して
も、上記効果が飽和するので、添加量の上限を0.０１％
とする。Ｚｒも、超硬工具寿命を改善する元素であつ
て、この効果を有効に得るためには、少なくとも0.０１
％を添加することが必要である。しかし、過多に添加し
ても、上記効果が飽和するので、添加量の上限を0.９％
とする。Ca is an element for improving the life of cemented carbide tools, and in order to effectively obtain this effect, at least 0.0
Addition of 005% is required. However, even if added too much, the above effect will be saturated, so the upper limit of the added amount is 0.01%.
And Zr is also an element for improving the life of cemented carbide tools, and in order to effectively obtain this effect, at least 0.01
% Needs to be added. However, even if added too much, the above effect will be saturated, so the upper limit of the amount added is 0.9%.
And
【００１７】次に、本発明による快削鋼は、上述した化
学成分を含有し、残部鉄及び不可避的不純物よりなると
共に、圧延方向に存在する硫化物介在物の平均面積が４
０μｍ2 以下であることが必要である。本発明によれ
ば、鋼にＳｉやＡｌを添加し、また、Ｏ含有量を規制し
て、介在物を圧延時に展伸しやすい硫化物介在物とし、
圧延後に分断させて、微細化する。また、本発明による
快削鋼の連続鋳造時の冷却速度を制御して、微細な硫化
物介在物を生成させる。このようにして、本発明鋼によ
れば、圧延方向に存在する硫化物介在物を一層微細化
し、その平均面積を４０μｍ2 以下と微細にすることに
よつて、すぐれた被切削性を確保しつつ、これを精密機
械部品に仕上げても、油漏れや空気漏れ等がない製品と
することができ、内部品質にすぐれる製品を得ることが
できる。Next, the free-cutting steel according to the present invention contains the above-mentioned chemical components, the balance is iron and inevitable impurities, and the average area of sulfide inclusions existing in the rolling direction is 4
It should be 0 μm 2 or less. According to the present invention, Si or Al is added to steel, and the O content is regulated so that the inclusions are sulfide inclusions that are easily expanded during rolling.
After rolling, it is cut into pieces and made finer. Further, the cooling rate during continuous casting of the free-cutting steel according to the present invention is controlled to generate fine sulfide inclusions. Thus, according to the steel of the present invention, the sulfide inclusions existing in the rolling direction are further refined and the average area thereof is refined to 40 μm 2 or less, whereby excellent machinability is secured. At the same time, even if this is finished into a precision machine part, a product free from oil leakage, air leakage, etc. can be obtained, and a product with excellent internal quality can be obtained.
【００１８】[0018]
【実施例】以下に実施例を挙げて本発明を説明するが、
本発明はこれら実施例により何ら限定されるものではな
い。表１及び表２に示す化学成分を有する鋼を溶製し
た。鋼ＡからＫが本発明鋼であり、鋼ａ１からｋは従来
鋼である。これら各鋼を２５mm径線材に圧延し、これを
冷間引抜きにて２２mm径棒鋼に加工して、性能試験に供
した。The present invention will be described below with reference to examples.
The present invention is not limited to these examples. Steels having the chemical compositions shown in Table 1 and Table 2 were melted. Steels A to K are steels of the present invention, and steels a1 to k are conventional steels. Each of these steels was rolled into a wire rod having a diameter of 25 mm, which was processed by cold drawing into a steel rod having a diameter of 22 mm, and subjected to a performance test.
【００１９】表１及び表２に示す硫化物介在物の寸法
は、鋼材圧延方向、縦断面表面、Ｄ／８、Ｄ／４部の2.
１６mm2 内に含まれるＭｎＳ単体及びＭｎＳ系複合介在
物を光学系にて２０倍に拡大し、幅が１μｍ以上の介在
物を画像解析して、測定したものである。The dimensions of the sulfide inclusions shown in Table 1 and Table 2 are 2. of the rolling direction of the steel material, the surface of the longitudinal section, D / 8, D / 4 part.
The MnS simple substance and MnS-based composite inclusions contained in 16 mm 2 were magnified 20 times by an optical system, and inclusions having a width of 1 μm or more were image-analyzed and measured.
【００２０】また、内部品質を評価するために、直径２
２mm、長さ３ｍの磨棒について、それぞれ２トンずつを
超音波探傷検査した。評価基準は、１５０μｍ以上の介
在物が皆無の場合を○、検出された磨棒数が重量％で２
％未満の場合を△、２％以上の場合を×で示す。結果を
表３及び表４に示す。更に、各鋼について、超硬工具
（Ｐ１０）、超硬コーテイング工具（ＴｉＮコーテイン
グ）、サーメツト工具及びセラミツク工具（Ａｌ2 Ｏ3
＋ＴｉＣ）の各工具にて切削したときの工具寿命を表３
及び表４に示す。切削条件は表５に示すとおりである。In order to evaluate the internal quality, the diameter of 2
An ultrasonic flaw detection test was conducted on 2 tons of each 2 mm and 3 m long polishing rod. The evaluation standard is ○ when there is no inclusion of 150 μm or more, and the number of detected polishing rods is 2 by weight%.
When it is less than%, Δ is shown, and when it is 2% or more, x is shown. The results are shown in Tables 3 and 4. Further, for each steel, a cemented carbide tool (P10), a cemented carbide coating tool (TiN coating), a thermite tool and a ceramic tool (Al 2 O 3
Table 3 shows the tool life when cutting with each tool (+ TiC)
And shown in Table 4. The cutting conditions are as shown in Table 5.
【００２１】[0021]
【表１】 [Table 1]
【００２２】[0022]
【表２】 [Table 2]
【００２３】[0023]
【表３】 [Table 3]
【００２４】[0024]
【表４】 [Table 4]
【００２５】[0025]
【表５】 [Table 5]
【００２６】発明鋼Ａ１、Ａ２及びＡ３は、従来鋼ａ
１、ａ２及びａ３の３つの鋼と同系の成分を有する。ａ
１鋼及びａ２鋼はいずれも連続鋳造材（ＣＣ）である
が、ａ１鋼ではＣ量が過多であり、ａ２鋼はＳ量が過少
であつて、本発明の目的とする被切削性の改善の効果を
得ることができない。発明鋼Ｂ１は、従来鋼ｂ１、ｂ２
及びｂ３の３つの鋼と同系の成分を有する。ｂ１鋼及び
ｂ２鋼は、いずれもＳｉ量が少なく、しかも、ｂ１鋼は
造塊材（ＩＣ）である。ｂ３鋼は、本発明による成分を
有するが、連続鋳造時の溶鋼の冷却速度を制御すること
なく、硫化物介在物の形状を微細化しなかつたものであ
る。発明鋼Ｂ１は、従来鋼ｂ１、ｂ２及びｂ３のいずれ
よりも、切削時の超硬工具寿命が長く、内部品質もすぐ
れている。Invention steels A1, A2 and A3 are conventional steels a
It has the same composition as the three steels of 1, a2 and a3. a
Both the 1st steel and the a2 steel are continuous cast materials (CC), but the a1 steel has an excessive amount of C, and the a2 steel has an excessive amount of S, which improves the machinability intended by the present invention. Can not get the effect of. The invention steels B1 are the conventional steels b1 and b2.
And b3 have the same composition as the three steels. Both the b1 steel and the b2 steel have a small amount of Si, and the b1 steel is an ingot material (IC). The b3 steel has the components according to the present invention, but the shape of the sulfide inclusions is not refined without controlling the cooling rate of the molten steel during continuous casting. The invention steel B1 has a longer carbide tool life during cutting and better internal quality than any of the conventional steels b1, b2 and b3.
【００２７】発明鋼Ｂ２は、Ａｌを積極的に添加してな
る発明鋼であつて、発明鋼Ｂ１よりも、一層超硬工具寿
命が長く、且つ、内部品質にもすぐれている。発明鋼Ｃ
は、従来鋼ｃ１、ｃ２及びｃ３の３つの鋼と同系の成分
を有する。ｃ１鋼は造塊材であり、ｃ２鋼は連続鋳造材
である。ｃ３鋼は、発明鋼と同じ成分を有するが、連続
鋳造時の溶鋼の冷却速度を制御することなく、硫化物介
在物の形状を微細化しなかつたものである。発明鋼Ｃ
は、従来鋼ｃ１、ｃ２及びｃ３のいずれよりも、切削時
の超硬工具寿命が長く、内部品質もすぐれている。Inventive steel B2 is an inventive steel in which Al is positively added, and has a longer cemented carbide tool life and superior internal quality than inventive steel B1. Invention Steel C
Has a composition similar to those of the three conventional steels c1, c2 and c3. The c1 steel is an ingot material and the c2 steel is a continuous cast material. The c3 steel has the same composition as the invention steel, but the shape of the sulfide inclusions is not refined without controlling the cooling rate of the molten steel during continuous casting. Invention Steel C
Has a longer carbide tool life during cutting and better internal quality than any of the conventional steels c1, c2 and c3.
【００２８】発明鋼Ｄは、同じくＢｉを添加した従来鋼
ｄよりも、発明鋼Ｅは、同じくＴｅを添加した従来鋼ｅ
よりも、発明鋼Ｆは、同じくＩｎを添加した従来鋼ｆよ
りも、発明鋼Ｇは、同じくＣａを添加した従来鋼ｇより
も、発明鋼Ｈは、同じくＺｒを添加した従来鋼ｈより
も、発明鋼Ｉは、同じくＰｂとＢｉを添加した従来鋼ｉ
よりも、発明鋼Ｊは、同じくＰｂとＴｅを添加した従来
鋼ｊよりも、また、発明鋼Ｋは、同じくＰｂとＣａを添
加した従来鋼ｋよりも、それぞれ切削時の超硬工具寿命
が長く、内部品質もすぐれている。The invention steel D is the same as the conventional steel d to which Bi is added, and the invention steel E is the same as the conventional steel e to which Te is added.
Inventive steel F is better than conventional steel f to which In is added, inventive steel G is better than conventional steel g to which Ca is also added, and inventive steel H is better than conventional steel h to which Zr is also added. Inventive steel I is a conventional steel i that also contains Pb and Bi.
Inventive steel J has a carbide tool life during cutting that is higher than that of conventional steel j that also contains Pb and Te, and that inventive steel K has a carbide tool life during cutting that that of conventional steel k that also contains Pb and Ca. It is long and has excellent internal quality.
【００２９】[0029]
【発明の効果】以上のように、本発明による快削鋼は、
所定の元素を含むと共に、圧延方向に存在する硫化物介
在物の平均面積を４０μｍ2 以下に微細化したので、超
硬工具による切削加工において、従来鋼に比べて、被削
性が一層すぐれると共に、内部品質にもすぐれる機械部
品を与える。As described above, the free-cutting steel according to the present invention is
Since the average area of sulfide inclusions existing in the rolling direction is reduced to 40 μm 2 or less as well as containing predetermined elements, machinability is further improved in cutting with cemented carbide tools compared to conventional steel. At the same time, it gives mechanical parts with excellent internal quality.
─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成６年６月１６日[Submission date] June 16, 1994
【手続補正１】[Procedure Amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】全文[Correction target item name] Full text
【補正方法】変更[Correction method] Change
【補正内容】[Correction content]
【書類名】 明細書[Document name] Statement
【発明の名称】超硬工具による被削性と内部品質にすぐ
れる快削鋼[ Title of Invention] Free-cutting steel with excellent machinability and internal quality by carbide tools
【特許請求の範囲】[Claims]
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は、超硬工具による被削用
快削鋼に関し、詳しくは、超硬工具、超硬コーテイング
工具、サーメツト工具及びセラミツク工具等（以下、こ
れらを単に超硬工具と総称する。）の超硬工具による被
削性と内部品質とにすぐれる連続鋳造による快削鋼に関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free-cutting steel for machining with a cemented carbide tool, and more specifically, a cemented carbide tool, a cemented carbide coating tool, a thermet tool, a ceramic tool, etc. simply collectively referred to as the carbide tools.) to be due to carbide tools of
It relates to free-cutting steel by continuous casting, which has excellent machinability and internal quality.
【０００２】[0002]
【従来の技術】一般に、ＡＩＳＩ １１系、１２系等の
Ｓ含有快削鋼は、圧延後、引抜き加工して、磨棒鋼とし
て自動盤切削用に供される。このような従来の快削鋼
は、上記した自動盤切削をはじめとして、高速度鋼工具
による被削性を良好にするために、鋼中へのＳｉ、Ａｌ
等の脱酸力の強い元素の添加を極力抑えて、鋼中のＭｎ
Ｓの形状を丸く、且つ、大きくしており、かかる快削鋼
は、高速度工具の寿命と鋼の切削仕上面にすぐれてい
る。このように、従来、快削鋼の被削性を高めるには、
介在物を大きくすることが有効であることが知られてい
る。2. Description of the Related Art In general, S-containing free-cutting steels such as AISI 11 series and 12 series are rolled and then drawn to be used as a bar steel for automatic lathe cutting. Such conventional free-cutting steel has Si and Al in the steel in order to improve machinability by a high-speed steel tool, including the automatic lathe cutting described above.
The addition of elements with strong deoxidizing power, such as
The shape of S is round and large, and such free-cutting steel is excellent in the life of the high-speed tool and the cutting surface finish of the steel. Thus, in order to improve the machinability of free-cutting steel,
It is known that increasing the size of inclusions is effective.
【０００３】しかし、最近の数値制御旋盤の普及によつ
て、１１系、１２系快削鋼でも、前記超硬工具による高
速切削加工が増えつつあることから、本発明者らは、既
に、特公平５−５１６５５号公報に記載されているよう
に、超硬工具による切削加工において被削性にすぐれる
快削鋼を開発している。一方において、油圧・空圧機械
部品に適用した場合に、油や空気漏れの原因となる大き
い介在物のない快削鋼の出現が待たれている。このよう
な要望に対しては、既に、例えば、電気製鋼、第６０巻
第３号第２８８〜２９１頁に「クリーン超快削鋼」なる
ものも提案されている。However, with the recent widespread use of numerically controlled lathes, high-speed cutting with the above-mentioned cemented carbide tools is increasing even for 11-series and 12-series free-cutting steels. As described in Japanese Patent Publication No. 5-51655, a free-cutting steel having excellent machinability in cutting with a cemented carbide tool is being developed. On the other hand, the appearance of free-cutting steel without large inclusions that cause oil or air leakage when applied to hydraulic / pneumatic mechanical parts is awaited. To meet such demand, for example, electric steelmaking, "clean ultra-free cutting steel", which has been proposed in Vol. 60, No. 3, pp. 288-291, has been already proposed.
【０００４】しかし、このように、近年に開発された快
削鋼によつても、最近のますます高まる高速切削加工
や、機械部品の高精度化、高気密化に対処するには十分
とはいえず、一層、被削性にすぐれると共に、内部品質
にもすぐれる快削鋼が強く要望されるに至つている。However, as described above, even the free-cutting steel developed in recent years is not enough to cope with the recent increasing high-speed cutting, high precision of machine parts, and high airtightness . Not to mention, there has been a strong demand for free-cutting steel that is superior in machinability and internal quality.
【０００５】[0005]
【発明が解決しようとする課題】従つて、本発明は、特
に、超硬工具による切削加工において、被削性にすぐれ
ると共に、内部品質にもすぐれる連続鋳造による快削鋼
を提供することを目的とする。Therefore, the present invention provides a free-cutting steel by continuous casting which is excellent in machinability and excellent in internal quality, especially in cutting with a cemented carbide tool. With the goal.
【０００６】[0006]
【課題を解決するための手段】本発明による超硬工具に
よる被削性と内部品質のすぐれる連続鋳造による削鋼の
第１は、重量％で Ｃ 0.０１〜0.２０％、Ｓｉ 0.１０〜0.６０％、Ｍ
ｎ 0.５〜２％、Ｐ 0.００５〜0.１２％、Ｓ 0.
１５〜0.４０％、Ｏ 0.００１〜0.０１０％、及びＮ
0.００３〜0.０３％を含有し、残部鉄及び不可避的
不純物よりなり、圧延方向に存在する硫化物介在物の平
均面積が４０μｍ2 以下であることを特徴とする。The first cutting steel by continuous casting which has excellent machinability and internal quality by the cemented carbide tool according to the present invention is C 0.01 to 0.20% by weight and Si 0. .10 to 0.60%, M
n 0.5-2%, P 0.005-0.12%, S 0.
15-0.40%, O 0.001-0.010%, and N
It is characterized in that it contains 0.003 to 0.03%, the balance is iron and unavoidable impurities, and the average area of sulfide inclusions existing in the rolling direction is 40 μm 2 or less.
【０００７】本発明による超硬工具による被削性と内部
品質のすぐれる連続鋳造による快削鋼の第２は、重量％
で (a) Ｃ 0.０１〜0.２０％、Ｓｉ 0.１０〜0.６０
％、Ｍｎ 0.５〜２％、Ｐ 0.００５〜0.１２％、Ｓ
0.１５〜0.４０％、Ｏ 0.００１〜0.０１０％、
及びＮ 0.００３〜0.０３％を含有し、更に、(b) Ａ
ｌ 0.００５〜0.０３％、Ｐｂ 0.４％以下、Ｂｉ 0.
４％以下、Ｔｅ 0.１％以下、Ｉｎ 0.２％以下、Ｃａ
0.０００５〜0.０１％、及びＺｒ 0.０１〜0.９％よ
りなる群から選ばれる少なくとも１種を含有し、残部鉄
及び不可避的不純物よりなり、圧延方向に存在する硫化
物介在物の平均面積が４０μｍ2 以下であることを特徴
とする。The second free-cutting steel produced by continuous casting, which has excellent machinability and internal quality by the cemented carbide tool according to the present invention, is% by weight.
(A) C 0.01 to 0.20%, Si 0.10 to 0.60
%, Mn 0.5-2%, P 0.005-0.12%, S
0.15 to 0.40%, O 0.001 to 0.010%,
And N 0.003 to 0.03%, and (b) A
l 0.005 to 0.03%, Pb 0.4% or less, Bi 0.0.
4% or less, Te 0.1% or less, In 0.2% or less, Ca
Sulfide inclusions containing at least one selected from the group consisting of 0.0005 to 0.01% and Zr 0.01 to 0.9%, the balance being iron and unavoidable impurities, and existing in the rolling direction. Is less than 40 μm 2 in average area.
【０００８】即ち、本発明によれば、鋼にＳｉを添加
し、鋼中の酸素を抑制することによつて、４０μｍ2 以
上の酸化物介在物や硫化物介在物や、或いはそれらの複
合介在物を減少させると共に、延性を有し、また、超硬
工具と反応し難い硫化物介在物を生成させることによつ
て、超硬工具による切削における工具寿命を大幅に向上
させ、更に、連続鋳造法によつて溶鋼の冷却速度を制御
し、介在物を微細化させる。本発明によれば、このよう
にして、鋼における元素と製造条件の最適化を図つて、
介在物を微細化させるので、介在物は、分塊や圧延後に
一層微細化し、かくして、超硬工具による被削性と内部
品質とが従来に比べて、一層改善された快削鋼を得るこ
とができる。That is, according to the present invention, by adding Si to steel to suppress oxygen in the steel, oxide inclusions or sulfide inclusions of 40 μm 2 or more, or composite inclusions thereof are provided. By reducing the amount of material, forming a sulfide inclusion that has ductility and is difficult to react with a cemented carbide tool, the tool life in cutting with a cemented carbide tool is greatly improved, and further continuous casting By the method, the cooling rate of molten steel is controlled and the inclusions are refined. According to the present invention, in this way, by optimizing the elements and manufacturing conditions in steel,
Since the inclusions are made finer, the inclusions are made finer after slabbing and rolling, thus obtaining a free-cutting steel in which the machinability and internal quality of the cemented carbide tool are further improved compared to the conventional one. You can
【０００９】先ず、本発明鋼において、必須の化学成分
の限定理由について説明する。Ｃは、過多に添加すると
きは、工具寿命を劣化させるので、Ｃ添加量の上限は0.
２０％とする。Ｓｉは、本発明鋼の超硬工具による被削
性と内部品質の改善のために必須の元素であつて、この
目的を達成するためには、少なくとも0.１０％を添加す
ることが必要である。しかし、過多に添加するときは、
鋼が硬さを増して、工具寿命を劣化させるので、添加量
の上限を0.６０％とする。First, the reasons for limiting the essential chemical components in the steel of the present invention will be explained. When C is added excessively, the tool life is deteriorated, so the upper limit of the amount of C added is 0.
20%. Si is a machinable material of the steel of the present invention
It is an essential element for improving the properties and internal quality, and it is necessary to add at least 0.10% to achieve this purpose. However, when adding too much,
Since steel increases hardness and deteriorates tool life, the upper limit of the addition amount is set to 0.60%.
【００１０】Ｍｎは、ＭｎＳを生成させ、ＦｅＳの生成
を抑制するために添加される。この効果を有効に得るた
めには、0.５０〜２％の範囲で添加することが必要であ
る。Ｐは、鋼の切削仕上面を改善するために、0.００５
〜0.１２％の範囲で添加される。Ｓは、本発明におい
て、鋼の被削性を改善する効果を有し、この効果を有効
に発現させるためには、少なくとも0.１５％を添加する
ことが必要であり、これよりも少ないときは、被削性の
改善効果に乏しい。しかし、過多に添加するときは、鋼
の機械的性質を著しく劣化させくので、添加量の上限は
0.４０％とする。Mn is added to produce MnS and suppress the production of FeS. In order to effectively obtain this effect, it is necessary to add it in the range of 0.50 to 2%. P is 0.005 to improve the cutting finish of steel.
It is added in the range of 0.12%. In the present invention, S has the effect of improving the machinability of steel, and in order to effectively exhibit this effect, it is necessary to add at least 0.15%, and when it is less than this Has a poor machinability improving effect. However, if too much is added, the mechanical properties of the steel will be significantly deteriorated, so the upper limit of the amount added is
It is 0.40%.
【００１１】Ｏは、過多に含有するときは、大きい酸化
物介在物が生成して、かかる鋼より製造される機械部品
の内部品質を劣化させる一方、超硬工具による切削に際
して、工具寿命を低下させ、更に、内部品質を改善する
硫化物介在物が生成しないので、本発明においては、そ
の含有量の上限を0.０１０％とする。このように、Ｏの
含有量は、少ない方がよいが、しかし、含有量を極端に
低減することは、そのために特別な処理を必要とするう
えに、低減することによる上記効果も飽和するので、含
有量の下限を0.００１％とする。[0011] O, when containing the excess generates large oxide inclusions, while degrading the internal quality of the machine parts produced from such steel, upon cutting with carbide tools, reduced tool life In addition, since no sulfide inclusions that improve the internal quality are formed, the upper limit of the content is set to 0.010% in the present invention. As described above, it is preferable that the content of O is small. However, if the content of O is extremely reduced, a special treatment is required for that purpose, and the above effect due to the reduction is saturated. , The lower limit of the content is 0.001%.
【００１２】Ｎは、構成刃先の生成量に影響を与える元
素であつて、切削仕上面粗さに影響を及ぼす。含有量が
0.００３％よりも少ないときは、その効果が少なく、他
方、0.０３％を越えるときは、表面疵が多くなるので、
Ｎ含有量は、0.００３〜0.０３％の範囲とする。本発明
による快削鋼は、上述した元素を必須として含有する
が、更に、下記から選ばれる少なくとも１種の元素を含
むことができる。[0012] N is an element that affects the amount of formation of the constituent cutting edge and affects the roughness of the finished surface. Content is
When it is less than 0.003%, the effect is small. On the other hand, when it is more than 0.03%, the surface defects are large.
The N content is in the range of 0.003 to 0.03%. The free-cutting steel according to the present invention essentially contains the above-mentioned elements, but may further contain at least one element selected from the following.
【００１３】Ａｌは、脱酸剤として、また、本発明鋼の
超硬工具による被削性の改善と内部品質の向上のために
用いられる元素であつて、このような効果を有効に発現
させるためには、少なくとも0.００５％を添加すること
が必要である。しかし、過多に添加するときは、鋼中に
Ａｌ2 Ｏ3 が生成し、却つて被削性に有害な影響を与え
るので、上限は0.０３％とする。Al is an element used as a deoxidizing agent and for improving the machinability and the internal quality of the steel of the present invention by the cemented carbide tool, and effectively exhibits such an effect. In order to do so, it is necessary to add at least 0.005%. However, if too much is added, Al 2 O 3 is produced in the steel and adversely affects the machinability , so the upper limit is made 0.03%.
【００１４】Ｐｂは、鋼の被削性を向上させる元素であ
って、好ましくは、0.０２％以上を添加する。Ｐｂは、
その添加量が多い程、鋼の被削性がよくなるが、反面、
Ｐｂの偏析度が大きくなるので、上限を0.４％とする。
Ｂｉも、鋼の被削性を向上させる元素であって、好まし
くは、0.０２％以上を添加する。Ｂｉも、その添加量が
多い程、鋼の被削性がよくなるが、反面、Ｂｉの偏析度
が大きくなるので、上限を0.４％とする。Pb is an element that improves the machinability of steel, and is preferably added in an amount of 0.02% or more. Pb is
The greater the amount added, the better the machinability of steel, but on the other hand,
The segregation degree of Pb increases, so the upper limit is made 0.4%.
Bi is also an element that improves the machinability of steel, and is preferably added in an amount of 0.02% or more. As for Bi, the machinability of steel improves as the amount of Bi added increases, but on the other hand, the segregation degree of Bi increases, so the upper limit is made 0.4%.
【００１５】Ｔｅも、鋼の被削性を向上させる元素であ
って、好ましくは、0.０１％以上を添加する。この元素
も、その添加量が多い程、鋼の被削性がよくなるが、反
面、熱間脆性を大きくして、表面疵を多くするので、上
限を0.１％とする。Ｉｎも、鋼の被削性を向上させる元
素であって、好ましくは、0.０１％以上を添加する。こ
の元素も、その添加量が多い程、鋼の被削性がよくなる
が、しかし、この元素は希少金属であり、高価であつ
て、過多に添加することは、経済性の点からも好ましく
ない。従つて、本発明においては、添加量を0.２％以下
とする。Te is also an element that improves the machinability of steel, and is preferably added in an amount of 0.01% or more. The higher the amount of this element added, the better the machinability of the steel, but on the other hand, the hot brittleness increases and the surface defects increase, so the upper limit is made 0.1%. In is also an element that improves the machinability of steel, and is preferably added in an amount of 0.01% or more. This element also improves the machinability of steel as the amount of addition increases, but this element is a rare metal, is expensive, and excessive addition is not preferable from the economical point of view. . Therefore, in the present invention, the addition amount is 0.2% or less.
【００１６】Ｃａは、超硬工具寿命を改善する元素であ
つて、この効果を有効に得るためには、少なくとも0.０
００５％の添加が必要である。しかし、過多に添加して
も、上記効果が飽和するので、添加量の上限を0.０１％
とする。Ｚｒも、超硬工具寿命を改善する元素であつ
て、この効果を有効に得るためには、少なくとも0.０１
％を添加することが必要である。しかし、過多に添加し
ても、上記効果が飽和するので、添加量の上限を0.９％
とする。Ca is an element for improving the life of cemented carbide tools, and in order to effectively obtain this effect, at least 0.0
Addition of 005% is required. However, even if added too much, the above effect will be saturated, so the upper limit of the added amount is 0.01%.
And Zr is also an element for improving the life of cemented carbide tools, and in order to effectively obtain this effect, at least 0.01
% Needs to be added. However, even if added too much, the above effect will be saturated, so the upper limit of the amount added is 0.9%.
And
【００１７】次に、本発明による快削鋼は、上述した化
学成分を含有し、残部鉄及び不可避的不純物よりなると
共に、圧延方向に存在する硫化物介在物の平均面積が４
０μｍ2 以下であることが必要である。本発明によれ
ば、鋼にＳｉやＡｌを添加し、また、Ｏ含有量を規制し
て、介在物を圧延時に展伸しやすい硫化物介在物とし、
圧延後に分断させて、微細化する。また、本発明による
快削鋼の連続鋳造時の冷却速度を制御して、微細な硫化
物介在物を生成させる。このようにして、本発明鋼によ
れば、圧延方向に存在する硫化物介在物を一層微細化
し、その平均面積を４０μｍ2 以下と微細にすることに
よつて、すぐれた被削性を確保しつつ、これを精密機械
部品に仕上げても、油漏れや空気漏れ等がない製品とす
ることができ、内部品質にすぐれる製品を得ることがで
きる。Next, the free-cutting steel according to the present invention contains the above-mentioned chemical components, the balance is iron and inevitable impurities, and the average area of sulfide inclusions existing in the rolling direction is 4
It should be 0 μm 2 or less. According to the present invention, Si or Al is added to steel, and the O content is regulated so that the inclusions are sulfide inclusions that are easily expanded during rolling.
After rolling, it is cut into pieces and made finer. Further, the cooling rate during continuous casting of the free-cutting steel according to the present invention is controlled to generate fine sulfide inclusions. As described above, according to the steel of the present invention, excellent machinability is secured by further refining the sulfide inclusions existing in the rolling direction and making the average area thereof finer than 40 μm 2. At the same time, even if this is finished into a precision machine part, a product free from oil leakage, air leakage, etc. can be obtained, and a product with excellent internal quality can be obtained.
【００１８】[0018]
【実施例】以下に実施例を挙げて本発明を説明するが、
本発明はこれら実施例により何ら限定されるものではな
い。表１及び表２に示す化学成分を有する鋼を溶製し
た。鋼ＡからＫが本発明鋼であり、鋼ａ１からｋは従来
鋼である。これら各鋼を２５mm径線材に圧延し、これを
冷間引抜きにて２２mm径磨棒に加工して、性能試験に供
した。The present invention will be described below with reference to examples.
The present invention is not limited to these examples. Steels having the chemical compositions shown in Table 1 and Table 2 were melted. Steels A to K are steels of the present invention, and steels a1 to k are conventional steels. Rolling each of these steel 25mm diameter line material, which was processed into a 22mm diameter Migakubo at cold drawing were subjected to performance tests.
【００１９】表１及び表２に示す硫化物介在物の寸法
は、鋼材圧延方向、縦断面表面、Ｄ／８、Ｄ／４部の2.
１６mm2 内に含まれるＭｎＳ単体及びＭｎＳ系複合介在
物を光学系にて２００倍に拡大し、幅が１μｍ以上の介
在物を画像解析して、測定したものである。The dimensions of the sulfide inclusions shown in Table 1 and Table 2 are 2. of the rolling direction of the steel material, the surface of the longitudinal section, D / 8, D / 4 part.
The MnS simple substance and the MnS-based composite inclusion contained in 16 mm 2 were magnified 200 times by an optical system, and the inclusion having a width of 1 μm or more was image-analyzed and measured.
【００２０】また、内部品質を評価するために、直径２
２mm、長さ３ｍの磨棒について、それぞれ２トンずつを
超音波探傷検査した。評価基準は、１５０μｍ以上の介
在物が皆無の場合を○、検出された磨棒数が重量％で２
％未満の場合を△、２％以上の場合を×で示す。結果を
表３及び表４に示す。更に、各鋼について、超硬工具
（Ｐ１０）、超硬コーテイング工具（ＴｉＮコーテイン
グ）、サーメツト工具及びセラミツク工具（Ａｌ2 Ｏ3
＋ＴｉＣ）の各工具にて切削したときの工具寿命を表３
及び表４に示す。切削条件は表５に示すとおりである。In order to evaluate the internal quality, the diameter of 2
An ultrasonic flaw detection test was conducted on 2 tons of each 2 mm and 3 m long polishing rod. The evaluation standard is ○ when there is no inclusion of 150 μm or more, and the number of detected polishing rods is 2 by weight%.
When it is less than%, Δ is shown, and when it is 2% or more, x is shown. The results are shown in Tables 3 and 4. Further, for each steel, a cemented carbide tool (P10), a cemented carbide coating tool (TiN coating), a thermite tool and a ceramic tool (Al 2 O 3
Table 3 shows the tool life when cutting with each tool (+ TiC)
And shown in Table 4. The cutting conditions are as shown in Table 5.
【００２１】[0021]
【表１】 [Table 1]
【００２２】[0022]
【表２】 [Table 2]
【００２３】[0023]
【表３】 [Table 3]
【００２４】[0024]
【表４】 [Table 4]
【００２５】[0025]
【表５】 [Table 5]
【００２６】発明鋼Ａ１、Ａ２及びＡ３は、従来鋼ａ
１、ａ２及びａ３の３つの鋼と同系の成分を有する。ａ
１鋼及びａ２鋼はいずれも連続鋳造材（ＣＣ）である
が、ａ１鋼ではＣ量が過多であり、ａ２鋼はＳ量が過少
であつて、本発明の目的とする被切削性の改善の効果を
得ることができない。発明鋼Ｂ１は、従来鋼ｂ１、ｂ２
及びｂ３の３つの鋼と同系の成分を有する。ｂ１鋼及び
ｂ２鋼は、いずれもＳｉ量が少なく、しかも、ｂ１鋼は
造塊材（ＩＣ）である。ｂ３鋼は、本発明による成分を
有するが、連続鋳造時の溶鋼の冷却速度を制御すること
なく、硫化物介在物の形状を微細化しなかつたものであ
る。発明鋼Ｂ１は、従来鋼ｂ１、ｂ２及びｂ３のいずれ
よりも、切削時の超硬工具寿命が長く、内部品質もすぐ
れている。Invention steels A1, A2 and A3 are conventional steels a
It has the same composition as the three steels of 1, a2 and a3. a
Both the 1st steel and the a2 steel are continuous cast materials (CC), but the a1 steel has an excessive amount of C, and the a2 steel has an excessive amount of S, which improves the machinability intended by the present invention. Can not get the effect of. The invention steels B1 are the conventional steels b1 and b2.
And b3 have the same composition as the three steels. Both the b1 steel and the b2 steel have a small amount of Si, and the b1 steel is an ingot material (IC). The b3 steel has the components according to the present invention, but the shape of the sulfide inclusions is not refined without controlling the cooling rate of the molten steel during continuous casting. The invention steel B1 has a longer carbide tool life during cutting and better internal quality than any of the conventional steels b1, b2 and b3.
【００２７】発明鋼Ｂ２は、Ａｌを積極的に添加してな
る発明鋼であつて、発明鋼Ｂ１よりも、一層超硬工具寿
命が長く、且つ、内部品質にもすぐれている。発明鋼Ｃ
は、従来鋼ｃ１、ｃ２及びｃ３の３つの鋼と同系の成分
を有する。ｃ１鋼は造塊材であり、ｃ２鋼は連続鋳造材
である。ｃ３鋼は、発明鋼と同じ成分を有するが、連続
鋳造時の溶鋼の冷却速度を制御することなく、硫化物介
在物の形状を微細化しなかつたものである。発明鋼Ｃ
は、従来鋼ｃ１、ｃ２及びｃ３のいずれよりも、切削時
の超硬工具寿命が長く、内部品質もすぐれている。Inventive steel B2 is an invented steel in which Al is positively added, and has a longer life of cemented carbide tools and is superior in internal quality to invented steel B1. Invention Steel C
Has a composition similar to those of the three conventional steels c1, c2 and c3. The c1 steel is an ingot material and the c2 steel is a continuous cast material. The c3 steel has the same composition as the invention steel, but the shape of the sulfide inclusions is not refined without controlling the cooling rate of the molten steel during continuous casting. Invention Steel C
Has a longer carbide tool life during cutting and better internal quality than any of the conventional steels c1, c2 and c3.
【００２８】発明鋼Ｄは、同じくＢｉを添加した従来鋼
ｄよりも、発明鋼Ｅは、同じくＴｅを添加した従来鋼ｅ
よりも、発明鋼Ｆは、同じくＩｎを添加した従来鋼ｆよ
りも、発明鋼Ｇは、同じくＣａを添加した従来鋼ｇより
も、発明鋼Ｈは、同じくＺｒを添加した従来鋼ｈより
も、発明鋼Ｉは、同じくＰｂとＢｉを添加した従来鋼ｉ
よりも、発明鋼Ｊは、同じくＰｂとＴｅを添加した従来
鋼ｊよりも、また、発明鋼Ｋは、同じくＰｂとＣａを添
加した従来鋼ｋよりも、それぞれ切削時の超硬工具寿命
が長く、内部品質もすぐれている。The invention steel D is the same as the conventional steel d to which Bi is added, and the invention steel E is the same as the conventional steel e to which Te is added.
Inventive steel F is better than conventional steel f to which In is added, inventive steel G is better than conventional steel g to which Ca is also added, and inventive steel H is better than conventional steel h to which Zr is also added. Inventive steel I is a conventional steel i that also contains Pb and Bi.
Inventive steel J has a carbide tool life during cutting that is higher than that of conventional steel j that also contains Pb and Te, and that inventive steel K has a carbide tool life during cutting that that of conventional steel k that also contains Pb and Ca. It is long and has excellent internal quality.
【００２９】[0029]
【発明の効果】以上のように、本発明による快削鋼は、
所定の元素を含むと共に、圧延方向に存在する硫化物介
在物の平均面積を４０μｍ2 以下に微細化したので、超
硬工具による切削加工において、従来鋼に比べて、被削
性が一層すぐれると共に、内部品質にもすぐれる機械部
品を与える。As described above, the free-cutting steel according to the present invention is
Since the average area of sulfide inclusions existing in the rolling direction is reduced to 40 μm 2 or less as well as containing predetermined elements, machinability is further improved in cutting with cemented carbide tools compared to conventional steel. At the same time, it gives mechanical parts with excellent internal quality.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 菅原 宏文 兵庫県神戸市灘区灘浜東町２番地 株式会 社神戸製鋼所神戸製鉄所内 (72)発明者 滝本 豊志 兵庫県神戸市灘区灘浜東町２番地 株式会 社神戸製鋼所神戸製鉄所内 (72)発明者 近藤 直哉 兵庫県神戸市灘区灘浜東町２番地 株式会 社神戸製鋼所神戸製鉄所内 (72)発明者 佐々木 敏彦 山口県下関市長府港町14番１号 株式会社 神戸製鋼所長府製造所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Sugawara, 2nd Nadahama Higashi-cho, Nada-ku, Kobe-shi, Hyogo Stock Company Kobe Steel Works, Kobe Steel Works (72) Inventor Toyoshi Takimoto 2nd Nada-hama-higashi, Nada-ku, Kobe-shi, Hyogo Stock company Kobe Steel Works Kobe Steel Works (72) Inventor Naoya Kondo 2 Nadahamahigashi-cho, Nada-ku, Kobe-shi, Hyogo Prefecture Kobe Steel Works Kobe Steel Works (72) Inventor Toshihiko Sasaki 14th Minato-cho, Shimonoseki City, Yamaguchi Prefecture No. 1 Kobe Steel Works Chofu Factory
Claims (2)
的不純物よりなり、圧延方向に存在する硫化物介在物の
平均面積が４０μｍ2 以下であることを特徴とする超硬
工具による被切削性と内部品質にすぐれる連続鋳造によ
る快削鋼。1. By weight%, C 0.01 to 0.20%, Si 0.10 to 0.60%, Mn 0.5 to 2%, P 0.005 to 0.12%, S 0.15 .About.0.40%, O 0.001 to 0.010%, and N 0.003 to 0.03%, the balance of iron and unavoidable impurities, and the average of sulfide inclusions existing in the rolling direction. Free-cutting steel by continuous casting with excellent machinability and internal quality by cemented carbide tools, characterized by having an area of 40 μm 2 or less.
鉄及び不可避的不純物よりなり、圧延方向に存在する硫
化物介在物の平均面積が４０μmm2 以下であることを特
徴とする超硬工具による被切削性と内部品質にすぐれる
連続鋳造による快削鋼。2. In weight%, (a) C 0.01 to 0.20%, Si 0.10 to 0.60%, Mn 0.5 to 2%, P 0.005 to 0.12%, S 0.15 to 0.40%, O 0.001 to 0.010%, and N 0.003 to 0.03%, and (b) Al 0.005 to 0.03%, Pb 0. From 0.4% or less, Bi 0.4% or less, Te 0.1% or less, In 0.2% or less, Ca 0.0005 to 0.01%, and Zr 0.01 to 0.9% Machinability and internal cutting by a cemented carbide tool characterized by containing at least one selected from the group consisting of balance iron and unavoidable impurities and having an average area of sulfide inclusions of 40 μmm 2 or less existing in the rolling direction. Free-cutting steel by continuous casting with excellent quality.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31840993A JPH07173573A (en) | 1993-12-17 | 1993-12-17 | Free-cutting steel excellent in machinability by carbide tool and internal quality |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP31840993A JPH07173573A (en) | 1993-12-17 | 1993-12-17 | Free-cutting steel excellent in machinability by carbide tool and internal quality |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07173573A true JPH07173573A (en) | 1995-07-11 |
Family
ID=18098836
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP31840993A Pending JPH07173573A (en) | 1993-12-17 | 1993-12-17 | Free-cutting steel excellent in machinability by carbide tool and internal quality |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07173573A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006062053A1 (en) * | 2004-12-06 | 2006-06-15 | Sumitomo Metal Industries, Ltd. | Low carbon free-cutting steel |
| WO2010071060A1 (en) * | 2008-12-16 | 2010-06-24 | Ｊｆｅ条鋼株式会社 | Low-carbon sulphur free-cutting steel |
| KR101314360B1 (en) * | 2005-08-30 | 2013-10-04 | 에이티아이 프로퍼티즈, 인코퍼레이티드 | Steel compositions, methods of forming the same, and articles formed therefrom |
| US9121088B2 (en) | 2007-08-01 | 2015-09-01 | Ati Properties, Inc. | High hardness, high toughness iron-base alloys and methods for making same |
| US9182196B2 (en) | 2011-01-07 | 2015-11-10 | Ati Properties, Inc. | Dual hardness steel article |
| US9593916B2 (en) | 2007-08-01 | 2017-03-14 | Ati Properties Llc | High hardness, high toughness iron-base alloys and methods for making same |
| US9657363B2 (en) | 2011-06-15 | 2017-05-23 | Ati Properties Llc | Air hardenable shock-resistant steel alloys, methods of making the alloys, and articles including the alloys |
-
1993
- 1993-12-17 JP JP31840993A patent/JPH07173573A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2006161087A (en) * | 2004-12-06 | 2006-06-22 | Sumitomo Metal Ind Ltd | Low carbon free cutting steel |
| WO2006062053A1 (en) * | 2004-12-06 | 2006-06-15 | Sumitomo Metal Industries, Ltd. | Low carbon free-cutting steel |
| KR101314360B1 (en) * | 2005-08-30 | 2013-10-04 | 에이티아이 프로퍼티즈, 인코퍼레이티드 | Steel compositions, methods of forming the same, and articles formed therefrom |
| US9121088B2 (en) | 2007-08-01 | 2015-09-01 | Ati Properties, Inc. | High hardness, high toughness iron-base alloys and methods for making same |
| US9951404B2 (en) | 2007-08-01 | 2018-04-24 | Ati Properties Llc | Methods for making high hardness, high toughness iron-base alloys |
| US9593916B2 (en) | 2007-08-01 | 2017-03-14 | Ati Properties Llc | High hardness, high toughness iron-base alloys and methods for making same |
| CN102245791A (en) * | 2008-12-16 | 2011-11-16 | Jfe条钢株式会社 | Low carbon sulfur free cutting steel |
| CN103882345A (en) * | 2008-12-16 | 2014-06-25 | Jfe条钢株式会社 | Low Carbon Resulfurized Free Cutting Steel |
| US8691141B2 (en) | 2008-12-16 | 2014-04-08 | JFE Bars and Shapes Corporation | Low carbon resulfurized free cutting steel |
| JP2010144187A (en) * | 2008-12-16 | 2010-07-01 | Jfe Bars & Shapes Corp | Low-carbon, sulfur-containing free-cutting steel having excellent surface roughness and having reduced surface flaw |
| EP2377964A4 (en) * | 2008-12-16 | 2017-06-07 | JFE Bars & Shapes Corporation | Low-carbon sulphur free-cutting steel |
| WO2010071060A1 (en) * | 2008-12-16 | 2010-06-24 | Ｊｆｅ条鋼株式会社 | Low-carbon sulphur free-cutting steel |
| US9182196B2 (en) | 2011-01-07 | 2015-11-10 | Ati Properties, Inc. | Dual hardness steel article |
| US10113211B2 (en) | 2011-01-07 | 2018-10-30 | Ati Properties Llc | Method of making a dual hardness steel article |
| US10858715B2 (en) | 2011-01-07 | 2020-12-08 | Ati Properties Llc | Dual hardness steel article |
| US9657363B2 (en) | 2011-06-15 | 2017-05-23 | Ati Properties Llc | Air hardenable shock-resistant steel alloys, methods of making the alloys, and articles including the alloys |
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