US20090110589A1 - Steel Material and Process for Producing the Same - Google Patents

Steel Material and Process for Producing the Same Download PDF

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Publication number
US20090110589A1
US20090110589A1 US12/083,353 US8335306A US2009110589A1 US 20090110589 A1 US20090110589 A1 US 20090110589A1 US 8335306 A US8335306 A US 8335306A US 2009110589 A1 US2009110589 A1 US 2009110589A1
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US
United States
Prior art keywords
steel member
drive shaft
steel
hardness
ratio
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.)
Abandoned
Application number
US12/083,353
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English (en)
Inventor
Yoshimi Usui
Yutaka Sato
Masahiko Igarashi
Wataru Yanagita
Hideo Watanabe
Satoru Nakamyo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honda Motor Co Ltd
Sanyo Special Steel Co Ltd
Original Assignee
Honda Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Assigned to HONDA MOTOR CO., LTD., SANYO SPECIAL STEEL CO., LTD. reassignment HONDA MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NAKAMYO, SATORU, IGARASHI, MASAHIKO, SATO, YUTAKA, USUI, YOSHIMI, WATANABE, HIDEO, YANAGITA, WATARU
Publication of US20090110589A1 publication Critical patent/US20090110589A1/en
Abandoned legal-status Critical Current

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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
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—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
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron

Definitions

  • the present invention relates to a steel member (material) and a method (process) for producing the same, particularly to a steel member suitable for a drive shaft, for example, and a method for producing the same.
  • Drive shafts for engines of automobiles are generally made of a steel member.
  • a steel member is required to be processed relatively easily by cutting work, etc.
  • the steel member needs to be high in shear stress, under which the member is broken by applying torsion torque, in other words, in torsion strength.
  • JIS-S40C equivalent materials are used as the steel member to obtain the drive shafts.
  • Patent Document 1 for example, a drive shaft composed of a steel member having predetermined constituent element composition ratio, surface hardness, martensite content, and hardening depth ratio is proposed to meet the demand.
  • Patent Document 2 a steel for induction hardening, which has ferrite crystal grain size and area ratio of ferrite structure to C component of predetermined values or less, is disclosed. According to Patent Document 2, this steel for induction hardening is suitable as a material for a drive shaft.
  • Patent Document 1 Japanese Laid-Open Patent Publication No. 10-036937
  • Patent Document 2 Japanese Laid-Open Patent Publication No. 2002-069566
  • a general object of the present invention is to provide a steel member useful for producing a small-sized member having excellent properties.
  • a principal object of the present invention is to provide a method for producing the steel member.
  • a steel member comprising, in percent by mass, 0.47% to 0.52% of C, 0.03% to 0.15% of Si, 0.6% to 0.7% of Mn, 0.005% to 0.03% of S, 0.025% to 0.04% of Ti, 0.05% to 0.3% of Cr, 0.04% to 0.09% of Mo, 0.02% to 0.04% of Al, and 0.0005% to 0.004% of B, the balance being iron and inevitable impurities, wherein the steel member has a surface with a Vickers hardness of 640 to 730, and when the steel member has a radius r and an effective hardening depth t that is a distance between the surface and a region with a Vickers hardness of 392, a hardened layer ratio t/r of the steel member is 0.4 or more.
  • the steel member can secure sufficient hardness and strength. This is because materials having high hardness generally show high strength. Further, the hardness of the steel member is not excessively high, so that the steel member is tough and is hardly brittle-fractured.
  • the steel member can be excellent in cutting properties.
  • a nitrogen content of the steel member is preferably 0.01% by mass or less.
  • BN and TiN are hardly generated. Therefore, the hardening of the member can proceed without inhibition thereof, and the member can be prevented from being reduced in the machinability and cutting properties due to excessively increased hardness.
  • a method for producing a steel member wherein the steel member has a surface with a Vickers hardness of 640 to 730, and when the steel member has a radius r and an effective hardening depth t that is a distance between the surface and a region with a Vickers hardness of 392, a ratio t/r of the steel member is 0.4 or more.
  • the method comprises subjecting a steel material to induction hardening, in which the steel material comprises, in percent by mass, 0.47% to 0.52% of C, 0.03% to 0.15% of Si, 0.6% to 0.7% of Mn, 0.005% to 0.03% of S, 0.025% to 0.04% of Ti, 0.05% to 0.3% of Cr, 0.02% to 0.04% of Al, and 0.0005% to 0.004% of B, the balance being iron and inevitable impurities, and has an occupied area ratio by ferrite of 30% or more and a B-scale Rockwell hardness of 85 to 95.
  • the steel member excellent in hardness, strength, and cutting properties can be obtained.
  • a small-sized member excellent in strength can be produced using the steel member having the above properties.
  • the steel member is excellent in the cutting properties and plastic deformability, and can be remarkably easily processed. Further, the steel member is excellent also in toughness, and thereby is hardly cracked in a processing step.
  • the steel member has high torsion strength, and thus can be suitably used as a material for a long shaft member such as a drive shaft.
  • the steel member excellent in strength, particularly torsion strength, and excellent in cutting properties can be produced.
  • FIG. 1 is an overall, longitudinal, schematic side view of a drive shaft comprising a steel member according to an embodiment of the present invention
  • FIG. 2 is a graph showing the relation between the hardness and the distance from the surface of the drive shaft of FIG. 1 ;
  • FIG. 3 is a table showing components and composition ratios of each steel member
  • FIG. 4 is a table showing properties of the steel members of FIG. 3 ;
  • FIG. 5 is a graph showing the relation between the shear stress and the hardened layer ratio r/t of the steel member of each Example.
  • FIG. 1 is an overall, longitudinal, schematic side view of a drive shaft 10 .
  • the drive shaft 10 is a long solid body, and a measurement site represented by the referential mark 12 in FIG. 1 has a diameter of 28 mm.
  • the drive shaft 10 comprises a steel member, which contains C, St, Mn, S, Ti, Cr, Mo, Al, and B in addition to iron and inevitable impurities.
  • C is a component for ensuring the strength and hardness, etc. of the drive shaft 10 after hardening and tempering treatments.
  • the composition ratio thereof is controlled to 0.47% to 0.52% (by mass, also the following composition ratio values are in percent by mass).
  • the composition ratio is less than 0.47%, it is difficult to ensure the hardness of the steel member.
  • it is more than 0.52%, the hardness is excessively increased, whereby it is difficult to process the steel member by plastic deformation, cutting, etc. and the drive shaft 10 is likely to be brittle-fractured with a lowered strength. Particularly, the cold working deformability of the steel member is reduced.
  • Si is an element useful for deoxidation of the drive shaft 10 , and the Si composition ratio of the drive shaft 10 is controlled to 0.03% to 0.15%.
  • the composition ratio is less than 0.03%, Si shows a poor deoxidation effect.
  • it is more than 0.15%, the hardness of the steel member is excessively increased, whereby it is difficult to process the steel member by plastic deformation, cutting, etc. Particularly, the cold working deformability of the steel member is reduced.
  • Mn acts to increase the induction hardening properties of the drive shaft 10 .
  • the drive shaft 10 has a significantly higher hardness after an induction hardening, as compared with before the hardening.
  • the Mn composition ratio is controlled to 0.6% to 0.7%, to reliably obtain this effect.
  • the composition ratio is more than 0.7%, the hardness of the steel member is excessively increased, whereby it is difficult to process the steel member by plastic deformation, cutting, etc. Particularly, the cold working deformability of the steel member is reduced.
  • S is a component that forms MnS together with Mn in the structure of the drive shaft 10 , thereby increasing the cutting properties of the drive shaft 10 .
  • the S composition ratio is controlled to 0.005% to 0.03%. When the composition ratio is less than 0.005%, it is difficult to increase the cutting properties. When it is more than 0.03%, particularly the cold working deformability of the steel member is reduced.
  • Ti acts to capture free N in the drive shaft 10 .
  • the Ti composition ratio is controlled to 0.025% to 0.04%.
  • Ti shows a poor free N capturing effect.
  • it is more than 0.04%, the steel member contains excessive Ti, so that the cutting properties and the cold working deformability of the member are reduced.
  • Cr is a component for improving the hardening properties of the drive shaft 10 .
  • the drive shaft 10 has a significantly higher hardness after a hardening treatment.
  • the Cr composition ratio is controlled to 0.05% to 0.3%. When the composition ratio is less than 0.05%, this effect is hardly obtained. On the other hand, when it is more than 0.3%, Cr is concentrated in cementite and prevents solid dissolution of carbon in the steel member during the hardening treatment.
  • Mo is an element useful for increasing the grain boundary strength of the drive shaft 10 after the hardening treatment, particularly the torsion strength.
  • the Mo composition ratio is controlled to 0.04% to 0.09%. When the composition ratio is less than 0.04%, the grain boundary strength is hardly increased. On the other hand, when it is more than 0.09%, the hardness of the steel member is excessively increased, whereby it is difficult to process the steel member by plastic deformation, cutting, etc. Particularly, the cold working deformability of the steel member is reduced.
  • B is a component for increasing the grain boundary strength, and for increasing the hardening properties of the drive shaft 10 . This effect is reduced when the steel member contains excessive N. This is because B forms BN together with the excessive N. Thus, as described above, N is captured by the predetermined amount of Ti to secure this effect.
  • the B composition ratio is controlled to 0.0005% to 0.004% (5 to 40 ppm).
  • the composition ratio is less than 5 ppm, B shows a poor effect of increasing the grain boundary strength.
  • it is more than 40 ppm, the hardening properties are reduced.
  • Al is a component that contributes to deoxidation in the same manner as Si.
  • the Al composition ratio is less than 0.02%, Al shows a poor deoxidation effect.
  • oxide impurities such as Al 2 O 3 are increased, so that the fatigue properties and plastic deformability of the steel member are deteriorated.
  • the upper limit of the Al composition ratio is 0.04%.
  • the N is bonded to B to form BN, so that the hardening properties, etc. are reduced as described above. Further, when the N is bonded to Ti to form TiN, the hardness of the steel member is excessively increased, so that the processing of the member is difficult, and the toughness is reduced.
  • the N (nitrogen) composition ratio of the drive shaft 10 is controlled to 0.01% or less to avoid such circumstances.
  • the occupied area ratio by ferrite observed in the structure of the drive shaft 10 is 30% or more.
  • the ratio of the area occupied by the ferrites to the entire visible area (100%) is 30% or more.
  • the drive shaft 10 is excellent in toughness after the hardening.
  • the surface hardness of the drive shaft 10 is such that the B-scale Rockwell hardness (H RB ) is 85 to 95. When the surface hardness is within the range, the strength of the drive shaft 10 is maintained after the hardening and tempering treatments.
  • the drive shaft 10 may be produced by subjecting a cylindrical workpiece, comprising the steel member having the above components and composition ratios, to turning or component rolling processing, etc.
  • the drive shaft 10 is then subjected to the hardening and tempering treatments.
  • an induction hardening method using high-frequency heating is adopted in the hardening treatment.
  • the surface of the drive shaft 10 is rapidly heated by a high-frequency induction current, and then the surface is rapidly cooled by spraying a cooling liquid.
  • the hardening conditions may be such that the induction current frequency is about 1 to 40 kHz, the induction current output is about 50 to 100 kW, and the heating time is 1 to 5 seconds.
  • the drive shaft 10 is subjected to the tempering treatment within a temperature range of 150° to 200° C.
  • the residual stress of the drive shaft 10 can be removed, and the secular change or cracking in the drive shaft 10 can be reduced.
  • the surface of the drive shaft 10 hardened and tempered as described above, has a Vickers hardness (H v ) of 640 to 730.
  • H v Vickers hardness
  • Such a steel member having high hardness generally show high strength, and the steel member is not insufficient in toughness if the hardness is within the above range.
  • the hardness is reduced in the radial direction from the surface to the inside as shown in FIG. 2 .
  • the hardness of the drive shaft 10 is measured from the surface, and the distance (depth) between the surface and a region with an H v of 392 is referred to as the effective hardened layer depth t.
  • the measurement site 12 has a diameter of 28 mm as described above, the value of 14 mm on the horizontal axis of the graph shown in FIG. 2 is at the radial direction center of the measurement site 12 .
  • the ratio of the effective hardened layer depth t to the radius r (the hardened layer ratio t/r) is 0.4 or more.
  • the ratio is less than 0.4, the thickness of the effective hardened layer is insufficient, whereby the drive shaft 10 is low in the torsion strength.
  • the drive shaft 10 excellent in the strength and toughness can be obtained.
  • the drive shaft 10 is described as an example of the steel member in the above embodiment, the final product of the steel member is not particularly limited thereto and may be another one such as an outer member of a constant-velocity Joint.
  • Ingots of steel members having components and composition ratios shown in FIG. 3 were prepared respectively using a vacuum melting furnace. Each ingot was heated at 950° C. and hot-forged to produce a cylindrical workpiece having a diameter of 27 mm. The temperature at the end of the forging was between the Ac3 point and 880° C.
  • Each cylindrical workpiece was observed using an optical microscope, to obtain the ferrite area ratio. Meanwhile, the H RB of the cylindrical workpiece, at the depth of 7 to 8 mm from the surface, was measured.
  • a small cylindrical workpiece having a diameter of 14 mm and a length of 21 mm was cut from the cylindrical workpiece. Then, the small cylindrical workpiece was subjected to an upset forming at a temperature within a cold working temperature range, and the upset ratio to crack initiation was obtained.
  • the cylindrical workpiece was subjected to a cutting test using ST20E (trade name, a cutting tool manufactured by Sumitomo Electric Industries, Ltd.) under conditions of a cutting speed of 150 m/minute, a cutting depth of 0.5 mm, and a feed speed of 0.2 mm/rev, and the abrasion loss of ST20E was measured after 12 minutes.
  • ST20E trade name, a cutting tool manufactured by Sumitomo Electric Industries, Ltd.
  • a drive shaft 10 having a shape shown in FIG. 1 was produced from each cylindrical workpiece, and the drive shaft 10 was subjected to induction hardening and tempering treatments under various conditions to change the effective hardened layer depth t and the hardened layer ratio t/r. Then, each drive shaft 10 was subjected to a static torsion test.
  • each steel member of Examples has a static torsion strength higher than that of the S40C equivalent material.

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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 Articles (AREA)
  • Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
US12/083,353 2005-10-11 2006-10-11 Steel Material and Process for Producing the Same Abandoned US20090110589A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2005296844A JP2007107029A (ja) 2005-10-11 2005-10-11 鋼材及びその製造方法
JP2005-296844 2005-10-11
PCT/JP2006/318885 WO2007043316A1 (ja) 2005-10-11 2006-09-22 鋼材及びその製造方法

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US (1) US20090110589A1 (enrdf_load_stackoverflow)
JP (1) JP2007107029A (enrdf_load_stackoverflow)
CN (1) CN101283111A (enrdf_load_stackoverflow)
WO (1) WO2007043316A1 (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110136580A1 (en) * 2008-09-12 2011-06-09 Hirokazu Ooba Power transmission shaft, drive shaft, and propeller shaft
US20120031211A1 (en) * 2009-04-23 2012-02-09 Ntn Corporation Shaft Part Formed With A Rolling Groove
EP2620513A4 (en) * 2010-09-22 2018-02-28 NTN Corporation Automobile part, manufacturing method for same and manufacturing device of same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5619668B2 (ja) * 2011-04-18 2014-11-05 本田技研工業株式会社 冷間打抜用鋼及びこれを用いたスチールベルト用エレメント
CN108149129A (zh) * 2016-12-05 2018-06-12 宜兴市零零七机械科技有限公司 一种改进的加工中心用传动轴材料

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060162823A1 (en) * 2003-01-17 2006-07-27 Yasuhiro Omori Steel product for induction hardening, induction-hardened member using the same, and methods producing them

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH108189A (ja) * 1996-06-14 1998-01-13 Daido Steel Co Ltd 曲げ特性に優れる高周波焼入れ用鋼ならびにその 鋼材を用いた曲げ特性に優れる高周波焼入れ部品
JPH10195589A (ja) * 1996-12-26 1998-07-28 Nippon Steel Corp 高捩り疲労強度高周波焼入れ鋼材
JP4344126B2 (ja) * 2002-10-03 2009-10-14 Ｊｆｅスチール株式会社 ねじり特性に優れる高周波焼もどし鋼
JP3733967B2 (ja) * 2003-01-17 2006-01-11 Ｊｆｅスチール株式会社 疲労特性に優れた鋼材およびその製造方法
JP2005048211A (ja) * 2003-07-30 2005-02-24 Jfe Steel Kk 疲労特性に優れた鋼材の製造方法

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060162823A1 (en) * 2003-01-17 2006-07-27 Yasuhiro Omori Steel product for induction hardening, induction-hardened member using the same, and methods producing them

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110136580A1 (en) * 2008-09-12 2011-06-09 Hirokazu Ooba Power transmission shaft, drive shaft, and propeller shaft
US8435125B2 (en) 2008-09-12 2013-05-07 Ntn Corporation Power transmission shaft, drive shaft, and propeller shaft
US20120031211A1 (en) * 2009-04-23 2012-02-09 Ntn Corporation Shaft Part Formed With A Rolling Groove
US8573081B2 (en) * 2009-04-23 2013-11-05 Ntn Corporation Shaft part formed with a rolling groove
EP2620513A4 (en) * 2010-09-22 2018-02-28 NTN Corporation Automobile part, manufacturing method for same and manufacturing device of same

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JP2007107029A (ja) 2007-04-26
WO2007043316A1 (ja) 2007-04-19
CN101283111A (zh) 2008-10-08

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Owner name: SANYO SPECIAL STEEL CO., LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:USUI, YOSHIMI;SATO, YUTAKA;IGARASHI, MASAHIKO;AND OTHERS;REEL/FRAME:020852/0623;SIGNING DATES FROM 20080226 TO 20080317

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