WO2003046240A1 - Acier de decolletage - Google Patents

Acier de decolletage Download PDF

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Publication number
WO2003046240A1
WO2003046240A1 PCT/JP2002/012559 JP0212559W WO03046240A1 WO 2003046240 A1 WO2003046240 A1 WO 2003046240A1 JP 0212559 W JP0212559 W JP 0212559W WO 03046240 A1 WO03046240 A1 WO 03046240A1
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WO
WIPO (PCT)
Prior art keywords
free
sulfide
mass
cutting steel
less
Prior art date
Application number
PCT/JP2002/012559
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English (en)
Japanese (ja)
Inventor
Kiyohito Ishida
Toshiyuki Murakami
Tetsuo Shiraga
Katsunari Oikawa
Original Assignee
Nkk Bars & Shapes Co., Ltd.
National Institute Of Advanced Industrial Science And Technology
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
Priority claimed from JP2002185494A external-priority patent/JP3891558B2/ja
Priority claimed from JP2002185496A external-priority patent/JP4295959B2/ja
Priority claimed from JP2002185495A external-priority patent/JP4295958B2/ja
Application filed by Nkk Bars & Shapes Co., Ltd., National Institute Of Advanced Industrial Science And Technology filed Critical Nkk Bars & Shapes Co., Ltd.
Priority to US10/495,902 priority Critical patent/US8124008B2/en
Priority to KR1020047008056A priority patent/KR100604119B1/ko
Priority to DE60222460T priority patent/DE60222460T2/de
Priority to EP02783714A priority patent/EP1449932B1/fr
Publication of WO2003046240A1 publication Critical patent/WO2003046240A1/fr

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    • 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
    • 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
    • C22C38/04—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
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Definitions

  • the present invention relates to free-cutting steel, and in particular, reduces the amount of lead-free or lead-added from 0.15 to 0.35 ma%, which is suitable as a substitute for conventional low-carbon sulfur composite free-cutting steel.
  • Japanese Patent Application Laid-Open No. Hei 9-255,539 discloses a Pb-free type in which the addition of Nd promotes the fine dispersion precipitation of MnS. A free-cutting non-heat treated steel is disclosed.
  • Japanese Patent Application Laid-Open No. 2000-160284 discloses that a large amount of S is added to increase the amount of sulfide, and that the form of sulfide is controlled by oxygen. A free-cutting steel with no added Pb is disclosed. Furthermore, in Japanese Patent Publication No.
  • Prior Art 3 by adding Cr, which is more likely to form a compound with S than Mn, Cr S instead of M n S is added. There is disclosed a free-cutting steel in which machinability is improved to improve machinability.
  • prior art 1 is a non-heat treated steel containing 0.2 to 0.6% of C :, and uses a special element, Nd. Therefore, it is not possible to sufficiently meet the demand for cost reduction. Further, in prior art 2, since a large amount of S is added, the hot ductility may be reduced. Furthermore, in Prior Art 3, the amount of expensive Cr added was 3.5 to 5.5.
  • Prior Art 4 discloses an increase in sulfide by adding a relatively large amount of S and a sulfide by Te. Control the shape of the object and reduce the amount of oxygen to 0.
  • a free-cutting steel is disclosed in which the machinability is improved by reducing the number of alumina classes to 0% or less.
  • Prior Art 5 Japanese Patent Publication No. 9446 (hereinafter referred to as Prior Art 5), sulfide is increased by adding a relatively large amount of S, and machinability is improved by adding Pb which is a free-cutting element.
  • Pb which is a free-cutting element.
  • sulfur and sulfur composite free-cutting steels generally contain a large amount of oxygen in order to control sulfide morphology effective for machinability.
  • all oxygen does not form a solid solution with sulfide, the formation of huge oxides Unavoidable, causing ground flaws, causing serious defects in processed products.
  • the amount of oxygen is set to 0.008% or less in order to avoid such flaws. Further, in the above prior art 2, the required amount of oxygen is reduced by increasing the amount of S added. Furthermore, in the above prior art 1, the required amount of oxygen is reduced by using Nd as a free-cutting element.
  • Prior Art 5 Although the amount of oxygen is limited to 0.008% or less, since the amount of oxygen is merely reduced, morphological control of sulfide is not sufficient as described above, and It is not sufficient from the viewpoint of machinability because the presence of sulfides has occurred. Also, in prior art 2, as described above, there is a concern that the hot ductility is reduced by S. Furthermore, prior art 1 has a problem in cost reduction as described above.
  • the first object of the present invention is to add no lead or to significantly reduce the amount of added lead compared to conventional low carbon / sulfur composite free-cutting steel, to prevent cost reduction, and to reduce hot ductility.
  • An object of the present invention is to provide a low-carbon free-cutting steel having a machinability equal to or higher than that of a conventional low-carbon sulfur composite free-cutting steel without lowering.
  • a second object of the present invention is to provide a low carbon / sulfur composite free-cutting steel having better machinability than before without increasing the amount of lead and sulfur.
  • the objective is to reduce the amount of oxygen compared to conventional steel containing the same amount of sulfur and lead, even though the amount of oxygen is smaller than before, without hindering cost reduction and without reducing hot ductility.
  • An object of the present invention is to provide a sulfur or sulfur composite free-cutting steel having excellent machinability and having less surface flaws at the time of rolling due to blowholes generated during fabrication by achieving low oxygen.
  • in mass% C: 0.02 to 0.15%, Mn: 0.05 to: L. 8%, S: 0.20 to 0.
  • C 0.02 to 0.15%
  • Mn 0.05 to: L.0.0%
  • S 0.20 to 0%. 4.9%
  • O 0.008 to over 0.030%
  • Pb 0.04 to 0.35%
  • Cr 0.3 to 2.3%
  • ma 3 contains 3: 0.16 to 0.49% at 3%, 0: 0.02 to 0.010%, and has a major axis of 10 Aim.
  • sulfide-based inclusions having the above particle diameters those with an aspect ratio of 5 or less account for 80% or more.Sulfur or sulfur composite free-cutting steel with low surface flaws and excellent machinability is available. Provided.
  • C 0.02 to 0.15%
  • Mn 0.05 to: L. 8%
  • S 0.1 to 0.6. 49%
  • O 0.02 to 0.010%
  • Cr 0.3 to 2.3%
  • the balance being Fe and unavoidable impurities
  • Cr / S Provided is a sulfur or sulfur composite free-cutting steel having a ratio in the range of 2 to 6 and having less surface flaws and excellent machinability
  • Figure 1 is a diagram for explaining the aspect ratio
  • FIG. 2 is a graph showing the relationship between the external tool life and the drill tool life.
  • the first free-cutting steel is a low-carbon free-cutting steel according to the first aspect described above.
  • C 0.02 to 0.15%
  • Mn 0.05 to: L. 8%
  • S 0.20 to 0.49%
  • 0 Over 0.01 to 0.03%
  • Cr 0.3 to 2.3%
  • the balance Fe and It consists of unavoidable impurities and has a CrZS ratio in the range of 2-6.
  • Si 0.1% or less
  • P 0.01 to 0.12%
  • A1 0.01% or less may be further contained.
  • C a 0.0001 to 0.005%
  • Pb 0.01 ⁇ 0.03%
  • S e 0.02 ⁇ 0.30%
  • T e 0.1 ⁇ 0.15%
  • B i 0.02 ⁇ 0.20%
  • Sn 0.03 to 0.020%
  • N 0.05 to 0.015%
  • Cu 0.05 ⁇ 0.50%
  • T i 0.03 ⁇ 0.09%
  • V 0.05 ⁇ 0.20%
  • Zr 0.005 ⁇ 0.0
  • It may further contain at least one selected from the group consisting of 90% and Mg: 0.0005 to 0.080%.
  • sulfide-based inclusions having a major diameter of 10 / im or more occupy 90% or more of all sulfide-based inclusions. Further, it is preferable that 80% or more of the sulfide-based inclusions having an aspect ratio of 5 or less among the sulfide-based inclusions having a long diameter of 10 // m or more. Further, it is preferable that such a free-cutting steel has a ferrite-perlite structure and the former austenite grain size is more than grain size number 7.
  • the present inventors have earnestly studied to achieve the first object and obtained the following findings.
  • the first free-cutting steel described above was obtained based on such knowledge, and as a result, lead was not added or the amount of lead added was significantly greater than that of conventional low-carbon sulfur composite free-cutting steel. It is possible to obtain machinability equal to or higher than that of conventional low-carbon sulfur composite free-cutting steel without hindering cost reduction and without reducing hot ductility.
  • the C is an important element because it greatly affects the strength and machinability of steel. However, if the content is less than 0.02 mass%, Unsatisfactory strength cannot be obtained. On the other hand, if the content exceeds 0.15 mass%, the strength becomes too high and the machinability deteriorates. Therefore, the C content is in the range of 0.02 to 0.15 mass%. Preferably, it is in the range of 0.02 to 0.10 mass%.
  • Mn is a sulfide-forming element important for machinability.
  • the content is set to be in the range of 0.05 to L; 8mass%. Preferably, it is not less than 0.22 mass% and less than 0.60 mass%.
  • S is a sulfide-forming element that forms a sulfide effective for machinability.
  • the content is less than 0.20 mass%, the effect on machinability is small because the amount of sulfide is small.
  • the S content is in the range of 0.20 to 0.49mass%.
  • O is an element effective in suppressing sulfide elongation during hot working such as rolling, and is an important element that can improve machinability by this action.
  • the content is less than 0.01111 & 33%, the effect of suppressing sulfide elongation is not sufficient, and the elongated sulfide remains, and the effect is not sufficiently exhibited.
  • the effect of suppressing sulfide elongation saturates.Addition of an excessive amount is economically disadvantageous and causes structural defects such as blowholes. I do. Therefore, the O content exceeds 0.01 The range is 0.03 mass%.
  • the Cr is an element that is effective in suppressing sulfide elongation during hot working such as rolling, and is an important element that can improve machinability by this action.
  • the content is less than 0.3 mass%, the effect of suppressing sulfide elongation is not sufficient, and a sufficient effect cannot be obtained because the elongated sulfide remains.
  • the effect of suppressing sulfide elongation saturates even if added in excess of 2.3% by mass, and the excessive addition is economically disadvantageous. Therefore, the Cr content is set in the range of 0.3 to 2.3 mAss%. Preferably, it is 0.3 to 1.5 mass%.
  • the Cr / S ratio is an important index that determines the degree of sulfide elongation during hot working such as rolling, and by defining this ratio, the desired elongation that can improve machinability Sulfide is obtained.
  • the ratio is less than 2, the elongation of sulfides due to the formation of Mn-S-only sulfides becomes prominent, resulting in poor machinability.
  • the ratio exceeds 6, the effect of suppressing sulfide elongation saturates. Therefore, Cr / S is in the range of 2 to 6. Preferably it is in the range of 2-4.
  • the first free-cutting steel has the above essential requirements, but the other requirements are as follows.
  • S i is a deoxidizing element, and the oxide of S i acts as a nucleus for sulfide formation, promoting the formation of sulfides to make sulfides finer and deteriorating the life of cutting tools. If you want to extend the It is preferable to control the content to 0.1 mass% or less. More preferably, it is not more than 0.03 mass%.
  • the P is an element that is effective in reducing the finished surface roughness by suppressing the formation of a component edge during cutting.
  • the content is less than 0.01 mass%, sufficient effects cannot be obtained, while if the content exceeds 0.12 mass%, the above effects are saturated and the hot workability is reduced. And the ductility is remarkably reduced. Therefore, the P content is in the range of 0.01 to 0.12 mass%. Preferably, it is in the range of 0.01 to 0.09 mass%.
  • a 1 is a deoxidizing element like Si, and the oxide of A 1 acts as a nucleus for sulfide formation, promotes sulfide formation, refines sulfides, and reduces the life of cutting tools Therefore, in order to further extend the tool life, the A 1 content is preferably set to 0.0 lmass% or less. More preferably, it is at most 0.003 mass%.
  • C a 0.00001 to 0.00.05 mass%
  • Pb 0.01 to 0.03 mass%
  • S e 0.02 to 0.30 m ass%
  • T e 0.1 to 0.15 ma ss%
  • B i 0.02 to 0.20 m ass%
  • S n 0.03 to 0.020 mass%
  • B 0.004 to 0.010 ma ss%
  • N 0.005 to 0.015 ma ss%
  • Cu 0.05 to 0. 5 0m ass%
  • Ti 0.03 to 0.09 0 ma ss%
  • V 0.05 0 to 0.20 ma ss%
  • Zr 0.05 0 to 0 90 mass%
  • Mg 0.0005 to 0.080 mass%.
  • the microstructure of the first free-cutting steel is a structure mainly composed of ferrite and powder.
  • a larger austenite grain size is more advantageous for machinability, but good machinability is maintained even with fine grains.
  • the particles finer it is preferable to make the particles finer than the particle size number 7 (the particle size according to the austenite particle size measurement method of JIS G0551). '' (1) Particle size of sulfide inclusions
  • the major axis is 10 m or more, and that the amount occupies 90% or more of the sulfide-based inclusions.
  • the aspect ratio of a sulfide-based inclusion is expressed as L / d, where L is the major axis of the sulfide-based inclusion and d is the minor axis.
  • L is the major axis of the sulfide-based inclusion
  • d is the minor axis.
  • the aspect ratio is preferably 5 or less, and the ratio of sulfide-based inclusions having such an aspect ratio is 80% or more of the sulfide-based inclusions having a major axis of 10 im or more. It is preferable to occupy
  • the second free-cutting steel is a low-carbon free-cutting steel according to the second aspect described above.
  • C 0.02 to 0.15%
  • Mn 0.05 to 1.
  • S 0.20 to 0.49%
  • 0 0.08 to over 0.30%
  • Pb 0.04 to 0.35%
  • Cr 0.3 to 2.3%
  • the balance being Fe and unavoidable impurities
  • the CrZS ratio is in the range of 2 to 6.
  • Si 0.1% or less
  • P 0.01 to 0.12%
  • A1 0.01% or less may be further contained.
  • C a 0.0001 to 0.0005%
  • S e 0.02 ⁇ 0.30%
  • Te 0.1 to 0.15%
  • Bi 0.02 to 0.20%
  • Sn 0.03 to 0.020%
  • B 0.004 to 0.010%
  • N 0.05 to 0.050%
  • Cu 0.05 to 0.50%
  • Ti 0.00 3 to 0.090%
  • V 0.05 to 0.20%
  • Zr 0.05 to 0.090%
  • Mg 0.00 05 to 0
  • at least one selected from the group consisting of 0.080% may be further contained.
  • the present inventors have conducted intensive studies to achieve the second object. As a result, the following findings were obtained.
  • the above-mentioned second free-cutting steel was obtained based on such knowledge, and as a result, exhibited better machinability than before without increasing the amount of lead and sulfur compared to the conventional one be able to.
  • the C content is set in the range of 0.02 to 0.15mass%. Preferably, it is in the range of 0.02 to 0.10 mass%.
  • Mn is a sulfide-forming element important for machinability. However, If the content is less than 0.05 mass%, sufficient machinability cannot be obtained because the amount of sulfide is too small. On the other hand, if the content exceeds 1.0 mass%, the sulfide elongates for a long time, and the machinability decreases. Therefore, the content of Mn is set in the range of 0.05 to: L.0.0 mass%. Preferably, it is at least 0.22 mass% and less than 0.60 mass%.
  • the S content is set in the range of 0.20 to 0.49mass%.
  • ⁇ is an element effective in suppressing the elongation of sulfide during hot working such as rolling, and is an important element that can improve machinability by this action.
  • the content is 0.008 mass% or less, the effect of suppressing the extension of sulfide is not sufficient, and the extended sulfide remains, and the effect is not sufficiently exhibited.
  • the addition of more than 0.030 mass% saturates the effect of suppressing sulfide elongation, and the addition of an excessive amount is economically disadvantageous and causes structural defects such as blowholes. I do. Therefore, the content should be in the range of more than 0.008 to 0.030 mass%.
  • Pb is an important element for improving machinability, but if its content is less than 0.04 mass%, its effect on machinability is small due to its small content. On the other hand, even if it exceeds 0.35 mass%, the improvement in machinability will be saturated and the hot workability will significantly decrease. Therefore, the Pb content should be in the range of 0.04 to 0.35 mass%. I do.
  • the Cr content is in the range of 0.3 to 2.3 mAss%. Preferably, it is 0.3 to 1.4 mass%.
  • the Cr / S ratio is also important for the second free-cutting steel, and if the ratio is less than 2, the Cn / S ratio increases due to the formation of Mn-S-only sulfide. Machinability deteriorates because sulfides become remarkable, and when the ratio exceeds 6, the effect of suppressing sulfide elongation saturates. Therefore, CrZS should be in the range of 2-6. Preferably it is in the range of 2-4.
  • Si degrades the life of the cutting tool, so if it is desired to further extend the life of the cutting tool, the content of Si should be regulated to 0.1 lmass% or less as in the first free-cutting steel. Is preferred. More preferably, it is not more than 0.03 m s s%.
  • the content of P is less than 0.01 mass%, the effect of reducing the finished surface roughness is not sufficiently exhibited, and the content of P is less than 0.1 mass%. If the content exceeds 12 mass%, the above effects are saturated and the hot workability and ductility are significantly reduced. Therefore, the P content is in the range of 0.01 to 0.12 mass%. Preferably, it is in the range of 0.01 to 0.09 mass%.
  • the content of A1 is preferably set to 0.01 mass% or less. More preferably, it is not more than 0.003 mass%.
  • V 0 0 0 5 0 2 0 0 m a s s%
  • Ca 0.00001 to 0.05 ma ss%
  • Se 0.02 to 0.30 ma ss%
  • Te 0.1 ⁇ 0.15 ma ss%
  • B i 0.02 ⁇ 0.2 0 ma ss%
  • S n 0.03 ⁇ 0.0 0.20 ma ss%
  • B 0.04 0 ⁇ 0 0.10 mass%
  • N 0.005 to 0.05 ma ss%
  • Cu 0.05 to 0.50 ma ss%
  • Ti 0.03 to 0. 0 9 0m ass%
  • V 0.005 to 0.20 ma ss%
  • Zr 0.05 to 0.00 90 ss%
  • Mg 0.000 0 5 to 0 .
  • the range is 0.80 mass%.
  • the microstructure of the second free-cutting steel is preferably a structure mainly composed of ferrite and light.
  • a larger former-stetenite grain size is more advantageous for machinability, but good machinability is maintained even with fine grains.
  • the third free-cutting steel is the sulfur or sulfur-combined free-cutting steel according to the third aspect described above.S: 0.16 to 0.49% and 0: 0.002 to Of the sulfide-based inclusions containing 0.010 and having a major axis of 10 zm or more, those with an aspect ratio of 5 or less account for 80% or more. While realizing such sulfide-based inclusions, the specific composition that defines C, which affects machinability, is as shown in the sulfur or sulfur composite free-cutting steel according to the fourth aspect above. In mass%, C: 0.02 to 0.15%, Mn: 0.05 to: L.
  • C a 0.00001 to 0.0900%
  • P b 0.01 ⁇ 0.40%
  • S e 0.02 ⁇ 0.30%
  • T e 0.03 ⁇ 0.15%
  • B i 0.02 ⁇ 0.20%
  • S n 0.03 to 0.020%
  • B 0.04 to 0.010%
  • N 0.05 to 0.015%
  • Cu 0. 0 5 to 0.50%
  • T i 0.03 to 0.09 0%
  • V 0.05 to 0.20%
  • Zr 0.005 to 0
  • at least one selected from the group consisting of 0.090% and Mg: 0.0005 to 0.080% may be further contained.
  • the present inventors have earnestly studied to achieve the third object and obtained the following findings.
  • the sulfide inclusions having an aspect ratio of 5 or less occupy 80% or more of the sulfide inclusions having a particle diameter of 10 / m or more, so that the sulfide inclusions are large.
  • the spindle shape even if the amount of oxygen is reduced as compared with the conventional steel, the machinability including the chip handling property and the surface roughness can be made equal to or higher than that of the conventional steel.
  • blow holes generated during manufacturing can be reduced as compared with conventional steel.
  • the reduction of blowholes reduces the occurrence of surface flaws during rolling from that point. As a result, the surface defects of the rolled material are reduced.
  • the third free-cutting steel described above was obtained based on such knowledge, and as a result, it did not hinder cost reduction and did not reduce the hot ductility, and it was less than before.
  • the machinability can be improved compared to conventional steel containing the same amount of sulfur and lead, despite the amount of oxygen, and blow holes generated during fabrication by achieving low oxygen. Surface defects at the time of rolling caused by the above can be reduced.
  • S is a sulfide-forming element that forms a sulfide effective for machinability.
  • the content is less than 0.16 mass%, the effect on machinability is small because the amount of sulfide is small.
  • the content exceeds 0.49 mass%, the hot workability and ductility are significantly reduced. Therefore, the S content is set in the range of 0.16 to 0.49mass%.
  • O is an element effective in suppressing sulfide elongation during hot working such as rolling, and is an important element that can improve machinability by this action.
  • the content is less than 0.02 mass%, the effect of suppressing sulfide elongation is not sufficient, Sulfide remains, and the effect is not fully exhibited.
  • 0 generates a professional hole at the time of forming, and a surface flaw is generated at the time of rolling with the hole as a starting point. Therefore, if the content is too large, it is harmful. ⁇ If the content exceeds 0.010 mass%, many such blowholes are generated, and the surface flaws during rolling tend to increase, and the effect of suppressing sulfide elongation increases. small. Therefore, the 0 content is in the range of 0.002 to 0.010 mass%.
  • the sulfide inclusions are large and formed in a spindle shape. For this reason, it is necessary that 80% or more of the large sulfide-based inclusions with a major axis of 10 m or more have an aspect ratio of 5 or less.
  • the C, Mn, Cr and CrZS ratios are specified as described above, in addition to S and O.
  • the C content is set in the range of 0.02 to 0.15mass%. Preferably, it is in the range of 0.02 to 0.10 mass%.
  • the Mn content is set to 0.05 to 1.8 mass%. Range. Preferably, it is at least 0.22 mass% and less than 0.60 mass%.
  • the Cr content is in the range of 0.3 to 2.3 ma s s%.
  • 0.3 to: L.5mass% is in the range of 0.3 to: L.5mass%.
  • the Cr / S ratio is important.If the ratio is less than 2, the formation of sulfides in the Mn-S only system The machinability deteriorates because the elongated sulfide becomes remarkable. When the ratio exceeds 6, the effect of suppressing the sulfide elongation saturates. Therefore, CrZS is in the range of 2-6. Preferably it is in the range of 2-4.
  • Si degrades the life of the cutting tool, so if you want to further extend the life of the cutting tool, use the same method as the first and second free-cutting steels.
  • Reduce the Si content to 0.1 lmass% or less. It is preferable to regulate. More preferably, it is at most 0.33 mass%.
  • the P content is less than 0.04 mass%, the effect of suppressing the formation of the built-up edge during P cutting is effectively exhibited, and the finished surface roughness is reduced. The effect of reducing is not effectively exhibited.
  • the content exceeds 0.12 mass%, the above effects are saturated and the hot workability and ductility are significantly reduced. Therefore, the P content is in the range of 0.04 to 0.12 mass%.
  • the content of A1 is preferably set to 0.01 mass% or less. More preferably, it is not more than 0.003 mass%.
  • V 0 0 0 5 0. 2 0 0 ma s s%
  • C a 0.00001 to 0.090 ma ss%
  • P b 0.01 to 0.40 ma ss%
  • S e 0.02 to 0.30 ma ss%
  • Te 0.03 to 0.15 ma ss%
  • Bi 0.02 to 0.20 mass%
  • Sn 0.00 3 to 0.020 ma ss%
  • B 0.004 to 0.010 ma ss%
  • N 0.005 to 0.015 ma ss%
  • Cu 0.05 to 0.50 ma ss%
  • Ti 0.03 to 0.09 0 ma ss%
  • V 0.05 to 0.20 ma ss%
  • Zr 0.00 5 To 0.090 mass%
  • Mg 0.0000 to 0.0080 mass%.
  • the microstructure of the third free-cutting steel is preferably a structure mainly composed of ferrite and light, like the first and second free-cutting steels. Larger prior austenite grain size is more advantageous for machinability, but good machinability is maintained even with fine grains. From the viewpoint of the mechanical properties of the product, it is preferable to make the grains finer than grain size number 7, similarly to the first and second free-cutting steels.
  • the method for producing the first to third free-cutting steels described above is not particularly limited, and the production and hot rolling can be performed under ordinary conditions.
  • the subsequent heat treatment is also not particularly limited. Normalization can be employed.
  • the morphological measurement of sulfide inclusions was performed by measuring the major axis L (length in the rolling direction) and the minor axis d for all sulfide inclusions in the 5.5 mm x 11 mm area in the middle of the bar. (Thickness, length in the direction perpendicular to the rolling direction) was measured by an image analyzer, and the proportion of sulfide-based inclusions with a major axis of 10 m or more and the proportion of sulfide-based inclusions with a major diameter of 10 m or more were measured. Of these, the ratio of those with an aspect ratio L / d of 5 or less was determined. The machinability test was performed under the conditions shown in Table 2.
  • Table 3 shows the test results.
  • Fig. 2 shows the relationship between the external tool life (SKH4) and the drill tool life as representative characteristic values.
  • No. 7 of the comparative example has an Mn amount exceeding the upper limit
  • No. 9 of the comparative example has a Cr amount less than the lower limit. 0 is small in mass, so the Cr / S of the comparative example No. 11 is less than the lower limit, so that the aspect ratio of sulfide is large and the machinability is lower than that of the present invention. Was inferior.
  • No. 8 in the comparative example since the S content was less than the lower limit, the total amount of sulfide-based inclusions effective for machinability was insufficient, and the machinability was also inferior to that of the present invention.
  • Table 5 shows the test results.
  • the examples of the present invention of Nos. 21 to 26 are all low carbon sulfur composite free-cutting steels of the reference examples of No. 32. It was confirmed that it had better characteristics as compared with.
  • the Mn amount exceeds the upper limit value, and in the comparative example No. 29, the Cr amount is less than the lower limit value. Since No. 30 has a smaller CrZS value than the lower limit, the No. 31 of the comparative example has a small mass, so that the aspect ratio of the sulfide is large and the machinability is lower than that of the present invention. Was also inferior. Also, in Comparative Example No. 28, since the S content was less than the lower limit, the total amount of sulfide-based inclusions effective for machinability was insufficient, and the machinability was also inferior to that of the present invention. . Table 5
  • Table 7 shows the test results.
  • No. 41 to No. 44 were all found in JISS UM 23 L, which is the reference example of No. 52.
  • No. 45 is an example in which the amount of S is the same and the amount of O is 1 Z 2 as compared with N 0.52 of the reference example of JISS UM 23 3 L. It had almost the same machinability as JISS UM23L of No. 52, and almost no surface flaws were found.
  • No. 46 has the same S content as No. 52 in the reference example, which is JISS UM 23 L, and has a smaller mass than No. 52 but more than No. 45 As an example, the machinability was better than No. 52.
  • Comparative Example No. 47 the Mn amount exceeded the upper limit, and in Comparative Example N0.49, the Cr amount was less than the lower limit.
  • the CrS was less than the lower limit value, so that the sulfide's aspect ratio was large in all cases, and the machinability was inferior to that of the present invention.
  • No. 48 since the S content was less than the lower limit, the total amount of sulfide-based inclusions effective for machinability was insufficient, and the machinability was also inferior to that of the present invention. Since the mass of No. 50 of the comparative example was less than the lower limit, the machinability was inferior to that of the example of the present invention.

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  • 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)

Abstract

Acier de décolletage ayant la composition chimique suivante, en pourcentage massique: C - de 0,02 à 0,15; Mn - de 0,05 à 1,8; S - de 0,20 à 0,49; O - de 0,01 à 0,03; Cr - de 0,3 à 2,3, le reste étant constitué de Fe et d'inévitables impuretés, à condition que le rapport Cr/S soit compris entre 2 et 6.
PCT/JP2002/012559 2001-11-30 2002-11-29 Acier de decolletage WO2003046240A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US10/495,902 US8124008B2 (en) 2001-11-30 2002-11-29 Free cutting steel
KR1020047008056A KR100604119B1 (ko) 2001-11-30 2002-11-29 쾌삭강
DE60222460T DE60222460T2 (de) 2001-11-30 2002-11-29 Automatenstahl
EP02783714A EP1449932B1 (fr) 2001-11-30 2002-11-29 Acier de decolletage

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
JP2001-366695 2001-11-30
JP2001366695 2001-11-30
JP2002-185494 2002-06-26
JP2002185494A JP3891558B2 (ja) 2001-11-30 2002-06-26 低炭素快削鋼
JP2002-185496 2002-06-26
JP2002185496A JP4295959B2 (ja) 2002-06-26 2002-06-26 表面疵の少ない被削性に優れた硫黄および硫黄複合快削鋼
JP2002-185495 2002-06-26
JP2002185495A JP4295958B2 (ja) 2002-06-26 2002-06-26 被削性に優れた低炭素硫黄複合快削鋼

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DE (1) DE60222460T2 (fr)
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WO (1) WO2003046240A1 (fr)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
WO2021132371A1 (fr) * 2019-12-23 2021-07-01 Ｊｆｅスチール株式会社 Acier de décolletage et son procédé de fabrication

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TWI391500B (zh) * 2008-08-06 2013-04-01 Posco 環保無鉛之快削鋼及其製作方法
RU2503737C1 (ru) * 2012-08-06 2014-01-10 Закрытое акционерное общество "Омутнинский металлургический завод" Автоматные висмутсодержащие стали
CN102965577A (zh) * 2012-11-26 2013-03-13 湖南华菱湘潭钢铁有限公司 一种易切削钢
CN103741077A (zh) * 2013-12-24 2014-04-23 中兴能源装备股份有限公司 一种钢材
TWI717990B (zh) * 2019-12-23 2021-02-01 日商杰富意鋼鐵股份有限公司 快削鋼及其製造方法
TWI779544B (zh) * 2020-03-31 2022-10-01 日商杰富意鋼鐵股份有限公司 易切削鋼及其製造方法
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
CN112795851B (zh) * 2020-12-29 2022-02-25 钢铁研究总院 一种低成本低合金半硬磁合金及其制备方法

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JPS63137147A (ja) * 1986-11-27 1988-06-09 Daido Steel Co Ltd 窒化可能な非調質快削鋼

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021132371A1 (fr) * 2019-12-23 2021-07-01 Ｊｆｅスチール株式会社 Acier de décolletage et son procédé de fabrication
JP6927444B1 (ja) * 2019-12-23 2021-09-01 Ｊｆｅスチール株式会社 快削鋼およびその製造方法
KR20220099571A (ko) * 2019-12-23 2022-07-13 제이에프이 스틸 가부시키가이샤 쾌삭강 및 그의 제조 방법
KR102705357B1 (ko) 2019-12-23 2024-09-09 제이에프이 스틸 가부시키가이샤 쾌삭강 및 그의 제조 방법

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EP1449932A1 (fr) 2004-08-25
KR100604119B1 (ko) 2006-07-25
KR20040060996A (ko) 2004-07-06
CN1276985C (zh) 2006-09-27
TW583315B (en) 2004-04-11
EP1449932A4 (fr) 2005-01-26
TW200300799A (en) 2003-06-16
EP1449932B1 (fr) 2007-09-12
CN1596320A (zh) 2005-03-16
DE60222460D1 (de) 2007-10-25
DE60222460T2 (de) 2008-06-19

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