JP6771580B2 - Structural material - Google Patents

Structural material Download PDF

Info

Publication number
JP6771580B2
JP6771580B2 JP2018550124A JP2018550124A JP6771580B2 JP 6771580 B2 JP6771580 B2 JP 6771580B2 JP 2018550124 A JP2018550124 A JP 2018550124A JP 2018550124 A JP2018550124 A JP 2018550124A JP 6771580 B2 JP6771580 B2 JP 6771580B2
Authority
JP
Japan
Prior art keywords
layer
carbide
carbides
scm420
martensite
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.)
Active
Application number
JP2018550124A
Other languages
Japanese (ja)
Other versions
JPWO2018088207A1 (en
Inventor
小室　又洋
又洋 小室
波東　久光
久光 波東
和也 野々村
和也 野々村
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of JPWO2018088207A1 publication Critical patent/JPWO2018088207A1/en
Application granted granted Critical
Publication of JP6771580B2 publication Critical patent/JP6771580B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/28—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • C23C8/32—Carbo-nitriding of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/02—Pretreatment of the material to be coated
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • C23C8/22—Carburising of ferrous surfaces
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/80—After-treatment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B2224/00—Materials of tools or workpieces composed of a compound including a metal
    • B23B2224/20—Tantalum carbide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B2224/00—Materials of tools or workpieces composed of a compound including a metal
    • B23B2224/28—Titanium carbide
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B2224/00—Materials of tools or workpieces composed of a compound including a metal
    • B23B2224/32—Titanium carbide nitride (TiCN)
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/06—Surface hardening
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/004—Dispersions; Precipitations
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite
    • 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
    • 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
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/40—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions
    • C23C8/52—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using liquids, e.g. salt baths, liquid suspensions more than one element being applied in one step
    • C23C8/54—Carbo-nitriding
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
    • C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Description

本発明は、低合金鋼の疲労強度上昇のための表面改質手法とそれを用いて作製した構造材に関する。 The present invention relates to a surface modification method for increasing the fatigue strength of low alloy steel and a structural material produced by using the method.

鉄系素材において機械的特性、耐食性、機能性向上のための組織制御の手法として表面硬化法が検討されている。例えば、特許文献１では表面硬化法を用いて製造した転動部材を開示する。 A surface hardening method is being studied as a method for controlling the structure of iron-based materials to improve mechanical properties, corrosion resistance, and functionality. For example, Patent Document 1 discloses a rolling member manufactured by using a surface hardening method.

特開２００６−００９１４５号公報Japanese Unexamined Patent Publication No. 2006-009145

特許文献１の転動部材では、マルテンサイトを母相とする第１焼入れ硬化層と、第１焼入れ硬化層より深い層に形成され、炭素が固溶されたマルテンサイト相およびベイナイト相の少なくとも一方を含有する母相中にセメンタイトが分散された第２焼入れ硬化層を具備する。特許文献１は強度向上を狙ったものであるが、特に疲労強度と耐摩耗性の面でさらなる向上が求められている。 In the rolling member of Patent Document 1, at least one of a first hardened hardened layer having martensite as a parent phase and a martensite phase and a bainite phase formed in a layer deeper than the first hardened hardened layer and in which carbon is solid-dissolved. It is provided with a second quenching hardened layer in which cementite is dispersed in a matrix containing. Patent Document 1 aims to improve the strength, but further improvement is particularly required in terms of fatigue strength and wear resistance.

本発明は、鉄及び炭素を含有する構造材であって、中心から表面に向かって、パーライトで構成する第１層、マルテンサイト及び炭化物の混合相で構成する第２層、炭化物で構成する第３層を有し、前記第３層の炭化物はMC（MはTi, V, Nb, Mo, Ta, Wの中の１つの元素）で示され、表面から中心に向かって、M元素濃度が減少する濃度勾配を有する。 The present invention is a structural material containing iron and carbon, from the center to the surface, a first layer composed of pearlite, a second layer composed of a mixed phase of martensite and carbides, and a first layer composed of carbides. It has three layers, and the carbide of the third layer is represented by MC (M is one element in Ti, V, Nb, Mo, Ta, W), and the concentration of M element increases from the surface to the center. It has a decreasing concentration gradient.

このように３層構造を採用することにより、疲労強度と耐摩耗性が向上した構造材を提供することができる。この構造材を摺動材などへの適用することで、従来と比較して構造材全体の軽量化や高寿命化、信頼性向上を図ることができる。 By adopting the three-layer structure in this way, it is possible to provide a structural material having improved fatigue strength and wear resistance. By applying this structural material to a sliding material or the like, it is possible to reduce the weight of the entire structural material, extend its life, and improve its reliability as compared with the conventional case.

断面部光学顕微鏡写真Cross-section optical micrograph ビッカース硬さ分布Vickers hardness distribution Ｘ線回折パターンX-ray diffraction pattern 断面組織の模式図Schematic diagram of cross-sectional structure 疲労試験の結果Fatigue test results

代表とする安価な構造材として低合金鋼が挙げられる。低合金鋼は添加元素がCrやMoなどの遷移金属元素含有量を20ｗｔ％以下とした鉄炭素系材料である。このような低合金鋼はA1変態点をもち、炭化物の形態が変態点の高温側と低温側とで大きく異なる材料である。すなわち、A1変態点より高温側ではγ(オーステナイト)や炭化物が成長し、低温側ではα(フェライト)と炭化物が形成でき、低温側に保持すると層状の炭化物が成長しやすくなる。ここで炭化物とはM3Cが主であり、MはFeおよびCrやMoなどの遷移金属元素である。Low alloy steel can be mentioned as a typical inexpensive structural material. Low alloy steel is an iron-carbon-based material in which the additive element is a transition metal element such as Cr or Mo with a content of 20 wt% or less. Such low alloy steel has an A1 transformation point, and the morphology of carbides is significantly different between the high temperature side and the low temperature side of the transformation point. That is, γ (austenite) and carbides grow on the high temperature side of the A1 transformation point, α (ferrite) and carbides can be formed on the low temperature side, and layered carbides tend to grow when held on the low temperature side. Here, the carbide is mainly M 3 C, and M is Fe and transition metal elements such as Cr and Mo.

炭化物の球状化のためには、層状炭化物の一部をγ相に溶解させ凝集することで表面エネルギー低下のために層状炭化物の分断が進行し、楕円形からさらに球状となる。球状化した炭化物以外の炭素はγ内に固溶する。このγ相からA1点以下でパーライトが成長し炭化物間に層状炭化物が形成され、さらにA1点より高温側に加熱することで層状炭化物が分断凝集する。このようなA1点の高温側と低温側で加熱冷却を繰り返すことで球状炭化物が成長する。なお、パーライトは層状組織でｂｃｃ構造のFe(α-Fe)とFe3Cが交互になった組織を意味する。 In order to spheroidize the carbide, a part of the layered carbide is dissolved in the γ phase and aggregated, so that the layered carbide is divided due to the decrease in surface energy, and the shape becomes more spherical from the elliptical shape. Carbon other than the spheroidized carbide dissolves in γ. Pearlite grows from this γ phase below the A1 point, layered carbides are formed between the carbides, and the layered carbides are split and aggregated by heating to a higher temperature side than the A1 point. By repeating heating and cooling on the high temperature side and the low temperature side of the A1 point, spherical carbide grows. In addition, pearlite means a layered structure in which Fe (α-Fe) and Fe3C having a bcc structure are alternated.

上記のように球状炭化物が成長し、その母地がγ相である温度範囲から急冷することにより母地をγ相からマルテンサイトと残留γ相の混合相に変態できる。マルテンサイト層の外側に高硬度の炭化物であるMC(MはTi, V, Nb, Mo, Ta, W の少なくとも1種)を形成するために浸炭工程の前にこれらのＭ元素を含有する粉末のスラリーを構造材表面に厚さ10-100μｍ塗布する。スラリーは粉末径10μｍ以下の不定形粉末とアルコール溶媒の混合体であり、大気中で複数回塗布する。その後乾燥、加熱し溶媒を蒸発させ、構造材のγ安定温度範囲に加熱する。この加熱によりＭ元素の一部が母材に拡散し、濃度勾配を形成する。次に一次浸炭によりMCが形成されるとともに母材側にも炭素が拡散する。 As described above, the spherical carbide grows, and the base material can be transformed from the γ phase to a mixed phase of martensite and the residual γ phase by quenching from the temperature range in which the base material is the γ phase. A powder containing these M elements prior to the carburizing step to form the hard carbide MC (M is at least one of Ti, V, Nb, Mo, Ta, W) on the outside of the martensite layer. The slurry of No. 1 is applied to the surface of the structural material to a thickness of 10-100 μm. The slurry is a mixture of an amorphous powder having a powder diameter of 10 μm or less and an alcohol solvent, and is applied multiple times in the air. After that, it is dried and heated to evaporate the solvent and heated to the γ stable temperature range of the structural material. By this heating, a part of M element is diffused in the base material to form a concentration gradient. Next, MC is formed by the primary carburizing and carbon is diffused to the base metal side as well.

M元素が母材の表面から約10μｍまで拡散することにより後に成長するMCの密着性が高まり、かつM元素の拡散による母材側のγ結晶粒成長が抑制でき、粒界及び粒内にM元素を含有する炭化物が成長し、マルテンサイトのラスやパケット微細化に寄与するとともにき裂伝搬を抑制する。 By diffusing the M element from the surface of the base material to about 10 μm, the adhesion of MC that grows later is enhanced, and the growth of γ crystal grains on the base material side due to the diffusion of the M element can be suppressed, and M is present at the grain boundaries and inside the grains. Carbides containing elements grow, which contributes to martensite lath and packet refinement and suppresses crack propagation.

上記浸炭時または浸炭後に窒素含有ガスを利用することで窒素マルテンサイトと炭窒素化合物の成長が可能となり、焼き戻し軟化抵抗の上昇や焼き入れ温度の低下による変形防止に寄与できる。 By using the nitrogen-containing gas during or after the carburizing, the nitrogen martensite and the carbon dioxide compound can grow, which can contribute to the prevention of deformation due to the increase in temper softening resistance and the decrease in quenching temperature.

本発明では、構造材の最表面から内部に向かって層構成が次のように変化する。最表面にはMC(MはTi, V, Nb, Mo, Ta, W の少なくとも1種)あるいはMCN(MはTi, V, Nb, Mo, Ta, W の少なくとも1種)系炭窒化物が成長しており、その厚さは10μm以上である。この高硬度炭化物または炭窒素化合物の内側に密着性を高めるためにＭ元素の拡散層が形成されており、母地はマルテンサイトである。マルテンサイトには球状炭化物が分散して成長している。マルテンサイトは構造材中心部に向かうと減少し、パーライトまたはフェライトとパーライトの混合相となる。本発明ではマルテンサイト母地に炭化物が分散しており、この炭化物に含有するＭ元素の濃度が表面側で高く、中心側で低くなる。また表層ほどマルテンサイトの組織が細かくなる。 In the present invention, the layer structure changes from the outermost surface of the structural material toward the inside as follows. MC (M is at least one of Ti, V, Nb, Mo, Ta, W) or MCN (M is at least one of Ti, V, Nb, Mo, Ta, W) on the outermost surface It is growing and its thickness is more than 10 μm. A diffusion layer of M element is formed inside this high-hardness carbide or carbon dioxide compound to enhance adhesion, and the base material is martensite. Spherical carbides are dispersed and grown on martensite. Martensite decreases toward the center of the structural material and becomes pearlite or a mixed phase of ferrite and pearlite. In the present invention, carbides are dispersed in the martensite base, and the concentration of M element contained in the carbides is high on the surface side and low on the center side. In addition, the martensite structure becomes finer on the surface.

上記M元素含有炭化物の形成により摺動部品の寿命が大幅に改善できる。 The life of sliding parts can be significantly improved by forming the above-mentioned M element-containing carbide.

実施例１〜４では、SCM420材を用いて構造材の特徴を説明するが、鉄及び炭化物を含んだものであれば寿命改善の効果を得られる。 In Examples 1 to 4, the characteristics of the structural material will be described using the SCM420 material, but if it contains iron and carbides, the effect of improving the life can be obtained.

なお、SCM420材はJIS規格で組成がＣ：０．１８〜０．２３、Ｓｉ：０．１５〜０．３５、Ｍｎ：０．６０〜０．９０、Ｐ：０．０３０以下、Ｓ：０．０３０以下、Ｎｉ：０．２５以下、Ｃｒ：０．９０〜１．２０、Ｍｏ：０．１５〜０．２５と定められており、実施例１〜４ではこの範囲を満たす１つの合金鋼を選択して用いた。 The SCM420 material has a JIS standard composition of C: 0.18 to 0.23, Si: 0.15 to 0.35, Mn: 0.60 to 0.90, P: 0.030 or less, S: 0. It is defined as .030 or less, Ni: 0.25 or less, Cr: 0.99 to 1.20, Mo: 0.15 to 0.25, and in Examples 1 to 4, one alloy steel satisfying this range. Was selected and used.

Tiをメタノール溶媒中で粉砕しTi粒子径が1-50μmの不定形とする。Ti粉砕粉を10ｗｔ％含有するメタノールをSCM420材(0.2wt%C, 0.3%Si, 0.7%Mn, 0.1%Cu, 0.1%Ni, 1.1%Cr, 0.2%Mo、残りFe)表面に大気中で塗布する。塗布後のTi厚さは200μmである。溶媒であるメタノールは蒸発乾燥させ、浸炭炉に挿入する。浸炭炉内を1Paまで真空排気後, Arで置換し炉内の雰囲気を清浄化する。 Ti is pulverized in a methanol solvent to form an amorphous Ti particle size of 1-50 μm. Methanol containing 10 wt% of Ti pulverized powder on the surface of SCM420 material (0.2 wt% C, 0.3% Si, 0.7% Mn, 0.1% Cu, 0.1% Ni, 1.1% Cr, 0.2% Mo, remaining Fe) in the air Apply. The Ti thickness after coating is 200 μm. Methanol, which is a solvent, is evaporated to dryness and inserted into a carburizing furnace. After vacuum exhausting the inside of the carburizing furnace to 1 Pa, replace it with Ar to purify the atmosphere inside the furnace.

H2OおよびO2分圧を減少させその時間変化が最小になったことを確認後、加熱を開始する。10℃/minの速度で1100℃に加熱し1h保持後アセチレン(C2H2)ガスを導入する。アセチレンガスの導入により構造材の表面から内部に拡散する。さらに、構造材の表面のTi、構造材の表面から内部に拡散したTiの一部が炭化する。この炭化によりTiはTiCあるいはTiCNとなる。炭素濃度は表面の方が内部より高い。Tiは1100℃の温度で拡散し、SCM420の粒界や粒内に拡散する。After reducing the H 2 O and O 2 partial pressures and confirming that the time change is minimized, start heating. Heat to 1100 ° C at a rate of 10 ° C / min, hold for 1 h, and then introduce acetylene (C 2 H 2 ) gas. By introducing acetylene gas, it diffuses from the surface of the structural material to the inside. Further, Ti on the surface of the structural material and a part of Ti diffused from the surface of the structural material to the inside are carbonized. By this carbonization, Ti becomes TiC or TiCN. The carbon concentration is higher on the surface than on the inside. Ti diffuses at a temperature of 1100 ° C and diffuses into the grain boundaries and grains of SCM420.

拡散したTiの一部は、アセチレン導入による炭素の拡散により，TiCを形成する。このTiCはSCM420のγ粒界で連続的に成長せず、粒状に成長する。1050℃での総炭素供給量はTiCとSCM420界面のSCM420側で1.2wt%である。 Part of the diffused Ti forms TiC by the diffusion of carbon by the introduction of acetylene. This TiC does not grow continuously at the γ grain boundaries of SCM420, but grows granularly. The total carbon supply at 1050 ° C is 1.2 wt% on the SCM420 side of the TiC-SCM420 interface.

1100℃で浸炭されたTiCとSCM420は、850℃に再加熱され、再度アセチレンガスにより浸炭する。850℃での総炭素供給量は1050℃での供給量よりも少なく, TiCとSCM420の界面のSCM420側で炭素濃度は1.4wt%である。この浸炭により粒内に球状炭化物を成長させる。浸炭後に油焼き入れ焼き戻す。油の温度は100℃、焼き戻し温度は160℃である。 TiC and SCM420 carburized at 1100 ° C are reheated to 850 ° C and carburized again with acetylene gas. The total carbon supply at 850 ° C is less than the supply at 1050 ° C, and the carbon concentration is 1.4 wt% on the SCM420 side of the interface between TiC and SCM420. By this carburizing, spherical carbides are grown in the grains. After carburizing, quench with oil and quench. The oil temperature is 100 ° C and the tempering temperature is 160 ° C.

上記工程で製造した構造材の組織は、深さ方向において中心から表面に向かって、３層構造を有する。第１層はパーライト、第２層はマルテンサイト及び炭化物の混合物、第３層は炭化物で構成する。第１層にはさらにフェライトを含み、パーライトとフェライトの混合物としても良い。 The structure of the structural material produced in the above step has a three-layer structure from the center to the surface in the depth direction. The first layer is composed of pearlite, the second layer is composed of a mixture of martensite and carbides, and the third layer is composed of carbides. The first layer may further contain ferrite and may be a mixture of pearlite and ferrite.

炭化物を形成せずに浸炭焼き入れ焼き戻した場合と比較して、回転曲げ疲労試験による疲労寿命は本実施例では20倍となる。このような高疲労寿命となる要因を以下に示す。TiCやTiCNが表面に厚さ200μmで形成され、硬さは1500〜3000Hvである。このTiCやTiCNがSCM420に分散した領域がSCM420とTiC系膜の間に形成され，TiCやTiCNの密着性を高めている。粒状TiCの周囲にはマルテンサイト及び残留オーステナイトが形成され,マルテンサイトの硬さは800Hvである。粒状TiCは材料中心では認められず，Ti及び炭素の拡散によって成長したものであり、表面から中心部にかけてTiCの量は減少し，炭化物はTiC系よりもFe3C系が増加する。このような構成となるため、表層に摩耗しにくい高硬度のTiCあるいはTiCN系膜が成長していること、分散した高硬度TiCとその周囲の微細マルテンサイト、Fe3Cとその周囲のマルテンサイトによってき裂の発生及び伝搬が抑制されている。The fatigue life by the rotary bending fatigue test is 20 times longer in this example than in the case of carburizing, quenching and tempering without forming carbides. The factors that lead to such a high fatigue life are shown below. TiC and TiCN are formed on the surface with a thickness of 200 μm, and the hardness is 1500 to 3000 Hv. A region in which TiC and TiCN are dispersed in SCM420 is formed between the SCM420 and the TiC-based membrane, which enhances the adhesion of TiC and TiCN. Martensite and retained austenite are formed around the granular TiC, and the hardness of martensite is 800 Hv. Granular TiC is not found in the center of the material, but is grown by diffusion of Ti and carbon. The amount of TiC decreases from the surface to the center, and the carbides increase in Fe 3 C system rather than in Ti C system. Due to such a configuration, a high-hardness TiC or TiCN-based film that is hard to wear is grown on the surface layer, dispersed high-hardness TiC and its surrounding fine martensite, and Fe 3 C and its surrounding martensite. The generation and propagation of cracks are suppressed by this.

SCM420材(0.2wt%C, 0.3%Si, 0.7%Mn, 0.1%Cu, 0.1%Ni, 1.1%Cr, 0.2%Mo 残りFe)の表面にAlを厚さ50μm蒸着後、Tiアセチルアセテートとフッ素を含有する溶液中でAlとTiの交換反応によってTiをめっきする。このTiめっき膜が成長したSCM420材を浸炭炉に挿入し、1100℃に加熱する。1100℃への加熱によりTiとSCM420の間で相互拡散が進み、TiはSCM420の粒界や粒内に拡散し一部はTiCとなる。Tiを拡散させた後，1050℃に降温しアセチレンを導入する。アセチレンの導入量は硬さが必要な深さと必要な組織（炭化物の量など）に依存するが、γ領域で1.2wt%まで炭素を導入させる。この一次浸炭で窒素ガス冷却によりSCM420の表層近傍で一部マルテンサイトを成長させる。このような冷却速度であればSCM420の粒界に10μmを超える炭化物は成長しない。 After depositing Al on the surface of SCM420 material (0.2wt% C, 0.3% Si, 0.7% Mn, 0.1% Cu, 0.1% Ni, 1.1% Cr, 0.2% Mo remaining Fe) to a thickness of 50 μm, Ti acetyl acetate and fluorine Ti is plated by the exchange reaction of Al and Ti in the solution containing. The SCM420 material on which this Ti plating film has grown is inserted into a carburizing furnace and heated to 1100 ° C. By heating to 1100 ° C, mutual diffusion progresses between Ti and SCM420, and Ti diffuses into the grain boundaries and grains of SCM420, and part of it becomes TiC. After diffusing Ti, the temperature is lowered to 1050 ° C and acetylene is introduced. The amount of acetylene introduced depends on the required depth of hardness and the required structure (amount of carbides, etc.), but carbon is introduced up to 1.2 wt% in the γ region. In this primary carburizing, some martensite is grown near the surface layer of SCM420 by cooling with nitrogen gas. At such a cooling rate, carbides exceeding 10 μm do not grow at the grain boundaries of SCM420.

冷却後A1点（共析変態点）以上の温度に加熱し、γ結晶粒内に炭化物を析出させる。析出した炭化物から炭素がSCM420内部に向かって拡散し、炭素濃度が減少するのを抑えるためにアセチレンを導入し炭素を表面から拡散させる。アセチレンの導入により炭化物が成長し粒状炭化物がγ結晶粒界や粒内に分散して成長しその粒径は0.5〜2μmとなる。この時炭素はTiCを通してSCM420に拡散する。 After cooling, it is heated to a temperature above the A1 point (emergence transformation point) to precipitate carbides in the γ crystal grains. Carbon diffuses from the precipitated carbide toward the inside of SCM420, and acetylene is introduced to prevent the carbon concentration from decreasing, and carbon is diffused from the surface. By the introduction of acetylene, carbides grow and granular carbides disperse and grow in γ grain boundaries and grains, and the particle size becomes 0.5 to 2 μm. At this time, carbon diffuses into SCM420 through TiC.

上記工程で製造した構造材の組織は、深さ方向において中心から表面に向かって、３層構造を有する。第１層はパーライト、第２層はマルテンサイト及び炭化物の混合物、第３層は炭化物で構成する。第１層にはさらにフェライトを含み、パーライトとフェライトの混合物としても良い。 The structure of the structural material produced in the above step has a three-layer structure from the center to the surface in the depth direction. The first layer is composed of pearlite, the second layer is composed of a mixture of martensite and carbides, and the third layer is composed of carbides. The first layer may further contain ferrite and may be a mixture of pearlite and ferrite.

1200MPaでの回転曲げ試験でマルテンサイトのみ表層に形成したSCM420試験片と比較すると破断する繰り返し数で、本実施例の試験片は50倍となった。このように疲労試験における寿命が延びることが確認できた。本実施例の構造材は摺動材として高寿命が不可欠な部材に適用でき、特に自動車用トルク伝達部品や繰り返し稼働部、回転部などの部品に使用可能である。 Compared with the SCM420 test piece in which only martensite was formed on the surface layer in the rotary bending test at 1200 MPa, the number of repetitions of fracture was 50 times that of the test piece of this example. In this way, it was confirmed that the life in the fatigue test was extended. The structural material of this embodiment can be applied to a member whose long life is indispensable as a sliding material, and can be particularly used for parts such as torque transmission parts for automobiles, repetitive moving parts, and rotating parts.

本実施例のように疲労寿命を確保するために必要な構成を以下に示す。
（１）構造材は２つの炭化物を有する。第１の炭化物はTiCを主成分とする化合物であり、第２の炭化物はM3C（MはTi, Cr, Mo）を主とする化合物であり、少なくとも２種類存在する。
（２）第１の炭化物は構造材の最表面に層状に形成され、一部にTiCN系化合物あるいはTiN系化合物を含んでいる。
（３）VC、VCNまたはVNのビッカース硬さが1500〜3500の範囲である。
（４）第１の炭化物の厚さは10μm以上200μm以下の範囲である。
（５）第２層と第３層の密着性確保のため、第１の炭化物の構成元素の少なくとも一種が中心部に向かって濃度勾配を有し、かつ第１層及び第２層に拡散した構成元素の少なくとも一種は粒界あるいは粒内に化合物として成長していること。The configuration required to secure the fatigue life as in this embodiment is shown below.
(1) The structural material has two carbides. The first carbide is a compound containing Ti C as a main component, and the second carbide is a compound mainly containing M 3 C (M is Ti, Cr, Mo), and there are at least two types.
(2) The first carbide is formed in layers on the outermost surface of the structural material, and partially contains a TiCN-based compound or a TiN-based compound.
(3) The Vickers hardness of VC, VCN or VN is in the range of 1500 to 3500.
(4) The thickness of the first carbide is in the range of 10 μm or more and 200 μm or less.
(5) In order to ensure the adhesion between the second layer and the third layer, at least one of the constituent elements of the first carbide has a concentration gradient toward the center and diffuses into the first layer and the second layer. At least one of the constituent elements must grow as a compound at the grain boundary or within the grain.

上記構成についてさらに説明する。1）炭化物はTiCを主成分とする化合物と、M3C（MはTi, Cr, Mo）を主とする炭化物の少なくとも2種類が形成されている。表面にTiを塗布した後に熱処理工程に入るため、Tiは表面で多く材料内部では少ない。Tiの拡散距離は1100℃で約100μmであるため，母材の表面と100μm深さではTiの濃度が10：1程度になる。母材であるSCM420の表面近傍ではTiの濃度が大きく変化するため，表面からTiC, TiCN系化合物の体積率が減少する。母材表面から深さ10μｍではTiC, TiCNに加えてM3Cが認められる。このM3CのMにはCr, Mo, Tiが含有している。The above configuration will be further described. 1) At least two types of carbides are formed: a compound containing TiC as a main component and a carbide mainly containing M3C (M is Ti, Cr, Mo). Since the heat treatment process is started after applying Ti on the surface, Ti is large on the surface and small on the inside of the material. Since the diffusion distance of Ti is about 100 μm at 1100 ° C, the concentration of Ti is about 10: 1 on the surface of the base metal and at a depth of 100 μm. Since the Ti concentration changes significantly near the surface of the base material SCM420, the volume fraction of TiC and TiCN compounds decreases from the surface. At a depth of 10 μm from the surface of the base metal, M3C is observed in addition to TiC and TiCN. Cr, Mo, and Ti are contained in M of this M 3 C.

Tiの濃度勾配が認められる深さ方向の距離は10μmから200μmの範囲である。このような濃度勾配は走査型電子顕微鏡による断面の組成分析、あるいはオージェ分析などで確認できる。Tiの濃度勾配を形成することで母材とTiC系層状膜との密着性が確保でき2000MPaで剥離しないTiC系膜により疲労寿命がTiC無の場合よりも50倍に向上する。 The distance in the depth direction where the concentration gradient of Ti is observed is in the range of 10 μm to 200 μm. Such a concentration gradient can be confirmed by composition analysis of a cross section using a scanning electron microscope, Auger analysis, or the like. By forming a Ti concentration gradient, the adhesion between the base material and the TiC-based layered film can be ensured, and the TiC-based film that does not peel off at 2000 MPa improves the fatigue life by 50 times compared to the case without TiC.

本実施例ではTiを塗布しているが、V, Nb, Mo, Ta, Wを塗布することでVC, NbC, MoC, TaC, WCが形成され、母材内部ではM3CのMにこれらの元素が置換した炭化物が形成される。In this example, Ti is applied, but by applying V, Nb, Mo, Ta, W, VC, NbC, MoC, TaC, WC are formed, and inside the base metal, these are applied to M of M 3 C. Carbides are formed in which the elements of

2）TiCを主とする炭化物は最表面で層状であり一部TiCN系あるいはTiN系化合物が認められ, 層状炭化物ではこれらの化合物の体積率はTiC>TiCN>TiNとなる。 2) Carbides mainly composed of TiC are layered on the outermost surface, and some TiCN-based or TiN-based compounds are observed. In layered carbides, the volume fraction of these compounds is TiC> TiCN> TiN.

3）上記TiC, TiCN あるいはTiNのビッカース硬さが1500〜3500の範囲であり、その厚さが10μm以上200μm以下の範囲であること。層状炭化物のビッカース硬さが1500未満の場合には、き裂が発生しやすくなり回転曲げ試験における寿命向上効果が顕著ではない。2000MPaにおける回転曲げ試験において、マルテンサイトのみの場合を1とするとTiを使用せずに所定の濃度・組織に制御して浸炭させた場合に5、Ti塗布後にTiC系層状炭化物を形成しかつ密着性を確保するためにTi拡散層を形成すると10〜50となる。このような飛躍的な寿命向上は層状炭化物(TiCなど)あるいは層状炭窒化物(TiCNなど),あるいは層状窒化物(TiNなど)のビッカース硬さが1500以上であることが必要であり、上記50倍の寿命向上には2500〜3000が望ましい。 3) The Vickers hardness of the above TiC, TiCN or TiN shall be in the range of 1500 to 3500, and the thickness shall be in the range of 10 μm or more and 200 μm or less. When the Vickers hardness of the layered carbide is less than 1500, cracks are likely to occur and the effect of improving the life in the rotary bending test is not remarkable. In the rotary bending test at 2000 MPa, assuming that only martensite is 1, it is 5 when it is carburized at a predetermined concentration and structure without using Ti, and TiC-based layered carbide is formed and adhered after Ti application. When a Ti diffusion layer is formed to ensure the property, it becomes 10 to 50. Such a dramatic improvement in life requires that the Vickers hardness of the layered carbide (TiC, etc.), the layered carbonitride (TiCN, etc.), or the layered nitride (TiN, etc.) is 1500 or more. 2500-3000 is desirable to double the life.

4)表層炭化物の密着性確保のため，表層炭化物の構成元素の少なくとも一種が母材の中心部に向かってTiについて0.5%/μmから10%/μmの濃度勾配を有している。またSCM420に拡散したTiは粒界あるいは粒内に化合物として成長しており、一部はM3Cというセメンタイトを形成する。4) In order to ensure the adhesion of the surface carbide, at least one of the constituent elements of the surface carbide has a concentration gradient of 0.5% / μm to 10% / μm for Ti toward the center of the base metal. In addition, Ti diffused in SCM420 grows as a compound at or within grains, and part of it forms cementite called M 3 C.

上記回転曲げ疲労試験における寿命向上以外にローラ試験におけるピッチング試験においても寿命向上効果を確認している。母材はSCM420以外に低合金鋼、肌焼鋼など汎用性のFeC系合金鋼であれば組成などを限定することなく、同様の効果が確認できる。 In addition to the life improvement in the rotary bending fatigue test, the life improvement effect has been confirmed in the pitching test in the roller test. If the base material is a general-purpose FeC-based alloy steel such as low alloy steel or hardened steel other than SCM420, the same effect can be confirmed without limiting the composition.

SCM420材(0.2wt%C, 0.3%Si, 0.7%Mn, 0.1%Cu, 0.1%Ni, 1.1%Cr, 0.2%Mo 残りFe)表面にメタノール溶媒にV粉末を10wt%混合しボールミルで粉砕する。V粉は0.01μmから10μmの範囲であり、メタノールとTi粉から構成されたスラリーを形成する。このスラリーをSCM420材に塗布乾燥させ，塗布膜の厚さを50μmとする。このV塗布膜が形成されたSCM420材を浸炭炉に挿入し、1200℃に加熱する。1200℃への加熱によりVとSCM420の間で相互拡散が進み、VはSCM420の粒界や粒内に拡散し一部はVCとなる。Vを拡散させた後，1050℃に降温しアセチレンを導入する。アセチレンの導入量は硬さが必要な深さと必要な組織（炭化物の量など）に依存するが，γ領域で1.2wt%まで炭素を導入させる。この一次浸炭でアルゴンガス冷却によりSCM420の表層近傍で一部マルテンサイトを成長させる。このような冷却速度であればSCM420の粒界に10μmを超える炭化物は成長しない。 SCM420 material (0.2wt% C, 0.3% Si, 0.7% Mn, 0.1% Cu, 0.1% Ni, 1.1% Cr, 0.2% Mo remaining Fe) Mix 10wt% of V powder with methanol solvent on the surface and crush with a ball mill. .. The V powder ranges from 0.01 μm to 10 μm and forms a slurry composed of methanol and Ti powder. This slurry is applied to SCM420 material and dried to make the thickness of the coating film 50 μm. The SCM420 material on which this V coating film is formed is inserted into a carburizing furnace and heated to 1200 ° C. By heating to 1200 ° C, mutual diffusion progresses between V and SCM420, and V diffuses into the grain boundaries and grains of SCM420, and part of it becomes VC. After diffusing V, the temperature is lowered to 1050 ° C and acetylene is introduced. The amount of acetylene introduced depends on the required depth of hardness and the required structure (amount of carbides, etc.), but carbon is introduced up to 1.2 wt% in the γ region. In this primary carburizing, some martensite is grown near the surface layer of SCM420 by cooling with argon gas. At such a cooling rate, carbides exceeding 10 μm do not grow at the grain boundaries of SCM420.

冷却後A1点（共析変態点）直下の700℃で1時間加熱保持後のA1点以上の温度に加熱し, γ結晶粒内に炭化物を析出させる。析出した炭化物から炭素がSCM420内部に向かって拡散し、炭素濃度が減少するのを抑えるためにアセチレンを導入し炭素を表面から拡散させる。アセチレンの導入により炭化物が成長し粒状炭化物がγ結晶粒界や粒内に分散して成長しその粒径は0.5〜2μmとなる。この時炭素はVCを通してSCM420に拡散する。 After cooling, it is heated to a temperature of A1 point or higher after heating and holding at 700 ° C. just below the A1 point (emergence transformation point) for 1 hour to precipitate carbides in the γ crystal grains. Carbon diffuses from the precipitated carbide toward the inside of SCM420, and acetylene is introduced to prevent the carbon concentration from decreasing, and carbon is diffused from the surface. By the introduction of acetylene, carbides grow and granular carbides disperse and grow in γ grain boundaries and grains, and the particle size becomes 0.5 to 2 μm. At this time, carbon diffuses into SCM420 through VC.

上記工程で製造した構造材の組織は、深さ方向において中心から表面に向かって、３層構造を有する。第１層はパーライト、第２層はマルテンサイト及び炭化物の混合物、第３層は炭化物で構成する。第１層にはさらにフェライトを含み、パーライトとフェライトの混合物としても良い。 The structure of the structural material produced in the above step has a three-layer structure from the center to the surface in the depth direction. The first layer is composed of pearlite, the second layer is composed of a mixture of martensite and carbides, and the third layer is composed of carbides. The first layer may further contain ferrite and may be a mixture of pearlite and ferrite.

1200MPaでの回転曲げ試験でマルテンサイトのみ表層に形成したSCM420試験片と比較すると破断する繰り返し数で、本実施例の試験片は50倍となった。このように疲労試験における寿命が延びることが確認できた。本実施例の構造材は摺動材として高寿命が不可欠な部材に適用でき、特に自動車用トルク伝達部品や繰り返し稼働部、回転部などの部品に使用可能である。 Compared with the SCM420 test piece in which only martensite was formed on the surface layer in the rotary bending test at 1200 MPa, the number of repetitions of fracture was 50 times that of the test piece of this example. In this way, it was confirmed that the life in the fatigue test was extended. The structural material of this embodiment can be applied to a member whose long life is indispensable as a sliding material, and can be particularly used for parts such as torque transmission parts for automobiles, repetitive moving parts, and rotating parts.

本実施例のように疲労寿命を確保するために必要な構成を以下に示す。
（１）構造材は２つの炭化物を有する。第１の炭化物はTiCを主成分とする化合物であり、第２の炭化物はM3C（MはTi, Cr, Mo）を主とする化合物であり、少なくとも２種類存在する。
（２）第１の炭化物は構造材の最表面に層状に形成され、一部にVCN系化合物あるいはVN系化合物を含んでいる。
（３）VC、VCNまたはVNのビッカース硬さが1500〜3500の範囲である。
（４）第１の炭化物の厚さは10μm以上200μm以下の範囲である。
（５）第２層と第３層の密着性確保のため、第１の炭化物の構成元素の少なくとも一種が中心部に向かって濃度勾配を有し、かつ第１層及び第２層に拡散した構成元素の少なくとも一種は粒界あるいは粒内に化合物として成長していること。The configuration required to secure the fatigue life as in this embodiment is shown below.
(1) The structural material has two carbides. The first carbide is a compound containing Ti C as a main component, and the second carbide is a compound mainly containing M 3 C (M is Ti, Cr, Mo), and there are at least two types.
(2) The first carbide is formed in layers on the outermost surface of the structural material, and partially contains a VCN-based compound or a VN-based compound.
(3) The Vickers hardness of VC, VCN or VN is in the range of 1500 to 3500.
(4) The thickness of the first carbide is in the range of 10 μm or more and 200 μm or less.
(5) In order to ensure the adhesion between the second layer and the third layer, at least one of the constituent elements of the first carbide has a concentration gradient toward the center and diffuses into the first layer and the second layer. At least one of the constituent elements must grow as a compound at the grain boundary or within the grain.

上記構成についてさらに説明する。1）炭化物はVCを主成分とする化合物と、M3C（MはV, Cr, Mo）を主とする炭化物の少なくとも2種類が形成されている。表面にVを塗布した後に熱処理工程に入るため、Vは表面で多く材料内部では少ない。Vの拡散距離は1100℃で約100μmであるため，母材の表面と100μm深さではVの濃度が10：1程度になる。母材であるSCM420の表面近傍ではVの濃度が大きく変化するため，表面からVC, VCN系化合物の体積率が減少する。母材表面から深さ10μｍではVC, VCNに加えてM3Cが認められる。このM3CのMにはCr, Mo, Vが含有している。The above configuration will be further described. 1) At least two types of carbides are formed: a compound containing VC as the main component and a carbide mainly containing M 3 C (M is V, Cr, Mo). Since the heat treatment process is started after V is applied to the surface, V is large on the surface and small on the inside of the material. Since the diffusion distance of V is about 100 μm at 1100 ° C, the concentration of V is about 10: 1 on the surface of the base metal and at a depth of 100 μm. Since the V concentration changes significantly near the surface of the base material SCM420, the volume fraction of VC and VCN compounds decreases from the surface. At a depth of 10 μm from the surface of the base metal, M 3 C is observed in addition to VC and VCN. Cr, Mo, and V are contained in M of this M3C.

Vの濃度勾配が認められる深さ方向の距離は10μmから200μmの範囲である。このような濃度勾配は走査型電子顕微鏡による断面の組成分析、あるいはオージェ分析などで確認できる。Tiの濃度勾配を形成することで母材とVC系層状膜との密着性が確保でき2000MPaで剥離しないVC系膜により疲労寿命がVC無の場合よりも50倍に向上する。 The distance in the depth direction where the concentration gradient of V is observed is in the range of 10 μm to 200 μm. Such a concentration gradient can be confirmed by composition analysis of a cross section using a scanning electron microscope, Auger analysis, or the like. By forming a Ti concentration gradient, the adhesion between the base material and the VC-based layered film can be ensured, and the VC-based film that does not peel off at 2000 MPa improves the fatigue life by 50 times compared to the case without VC.

本実施例ではVを塗布しているが、Ti, Nb, Mo, Ta, W，Crを一種以上塗布することでTiC, NbC, MoC, TaC, WC，(Ti,Cr)CなどのMC化合物が形成され、母材内部ではM3CのMにこれらの元素が置換した炭化物が形成される。 In this example, V is applied, but by applying one or more of Ti, Nb, Mo, Ta, W, Cr, MC compounds such as TiC, NbC, MoC, TaC, WC, (Ti, Cr) C are applied. Is formed, and carbides in which these elements are substituted are formed in M of M3C inside the base metal.

2）VCを主とする炭化物は最表面で層状であり一部VCN系あるいはVN系化合物が認められ, 層状炭化物ではこれらの化合物の体積率はVC>VCN>VNとなる。 2) Carbides mainly composed of VC are layered on the outermost surface, and some VCN-based or VN-based compounds are recognized. In layered carbides, the volume fraction of these compounds is VC> VCN> VN.

3）上記VC, VCN あるいはVNのビッカース硬さが1500〜3500の範囲であり、その厚さが10μm以上200μm以下の範囲であること。層状炭化物のビッカース硬さが1500未満の場合には, き裂が発生しやすくなり回転曲げ試験における寿命向上効果が顕著ではない。2000MPaにおける回転曲げ試験において、マルテンサイトのみの場合を1とするとVを使用せずに所定の濃度・組織に制御して浸炭させた場合に5、V塗布後にVC系層状炭化物を形成しかつ密着性を確保するためにV拡散層を形成すると10〜50となる。このような飛躍的な寿命向上は層状炭化物(VCなど)あるいは層状炭窒化物(VCNなど),あるいは層状窒化物(VNなど)のビッカース硬さが1500以上であることが必要であり、上記50倍の寿命向上には2500〜3000が望ましい。 3) The Vickers hardness of the above VC, VCN or VN shall be in the range of 1500 to 3500, and the thickness shall be in the range of 10 μm or more and 200 μm or less. When the Vickers hardness of the layered carbide is less than 1500, cracks are likely to occur and the effect of improving the life in the rotary bending test is not remarkable. In the rotary bending test at 2000 MPa, assuming that only martensite is 1, when carburized at a predetermined concentration and structure without using V5, VC-based layered carbides are formed and adhered after V application. When a V diffusion layer is formed to ensure the property, it becomes 10 to 50. Such a dramatic improvement in life requires that the Vickers hardness of the layered carbide (VC, etc.), layered carbonitride (VCN, etc.), or layered nitride (VN, etc.) be 1500 or more. 2500-3000 is desirable to double the life.

4)表層炭化物の密着性確保のため，表層炭化物の構成元素の少なくとも一種が母材の中心部に向かってVについて0.5%/μmから10%/μmの濃度勾配を有している。またSCM420に拡散したVは粒界あるいは粒内に化合物として成長しており、一部はM3Cというセメンタイトを形成する。 4) In order to ensure the adhesion of the surface carbide, at least one of the constituent elements of the surface carbide has a concentration gradient of 0.5% / μm to 10% / μm with respect to V toward the center of the base metal. In addition, V diffused in SCM420 grows as a compound at the grain boundary or in the grain, and a part of it forms cementite called M3C.

上記回転曲げ疲労試験における寿命向上以外にローラ試験におけるピッチング試験においても寿命向上効果を確認している。母材はSCM420以外に低合金鋼、肌焼鋼など汎用性のFeC系合金鋼であれば組成などを限定することなく、同様の効果が確認できる。 In addition to the life improvement in the rotary bending fatigue test, the life improvement effect has been confirmed in the pitching test in the roller test. If the base material is a general-purpose FeC-based alloy steel such as low alloy steel or hardened steel other than SCM420, the same effect can be confirmed without limiting the composition.

Tiをメタノール溶媒中で粉砕しTi粒子径が1-50μmの不定形とする。Ti粉砕粉を10ｗｔ％含有するメタノールをSCM420材(0.2wt%C, 0.3%Si, 0.7%Mn, 0.1%Cu, 0.1%Ni, 1.1%Cr, 0.2%Mo 残りFe)表面に大気中で塗布する。塗布後のTi厚さは20μmである。溶媒であるメタノールは蒸発乾燥させ、浸炭炉に挿入する。浸炭炉内を1Paまで真空排気後, Arで置換し炉内の雰囲気を清浄化する。 Ti is pulverized in a methanol solvent to form an amorphous Ti particle size of 1-50 μm. Methanol containing 10 wt% of Ti pulverized powder is applied to the surface of SCM420 material (0.2 wt% C, 0.3% Si, 0.7% Mn, 0.1% Cu, 0.1% Ni, 1.1% Cr, 0.2% Mo remaining Fe) in the air. To do. The Ti thickness after coating is 20 μm. Methanol, which is a solvent, is evaporated to dryness and inserted into a carburizing furnace. After vacuum exhausting the inside of the carburizing furnace to 1 Pa, replace it with Ar to purify the atmosphere inside the furnace.

H2OおよびO2分圧を減少させその時間変化が最小になったことを確認後、加熱を開始する。10℃/minの速度で1100℃に加熱し1h保持後アセチレン(C2H2)ガスを導入する。アセチレンガスの導入により表面のTi, およびSCM420の表面から拡散したTiの一部が炭化し，SCM420の表面に炭素が拡散する。炭素濃度は表面Ti>SCM420表面であり、TiはTiCあるいはTiCNとなる。Tiは1100℃の温度で拡散しSCM420の粒界や粒内に拡散する。
拡散したTiの一部は、アセチレン導入による炭素の拡散により，TiCあるいは(Ti, Cr, Mo)3Cを形成する。このTiCはSCM420のγ粒界で連続的に成長せず、粒状に成長する。1050℃での総炭素供給量はTiC/SCM420界面のSCM420側で1.2wt%である。After reducing the H 2 O and O 2 partial pressures and confirming that the time change is minimized, start heating. Heat to 1100 ° C at a rate of 10 ° C / min, hold for 1 h, and then introduce acetylene (C 2 H 2 ) gas. Due to the introduction of acetylene gas, Ti on the surface and a part of Ti diffused from the surface of SCM420 are carbonized, and carbon is diffused on the surface of SCM420. The carbon concentration is surface Ti> SCM420 surface, where Ti is TiC or TiCN. Ti diffuses at a temperature of 1100 ° C and diffuses into the grain boundaries and grains of SCM420.
Part of the diffused Ti forms Ti C or (Ti, Cr, Mo) 3 C by the diffusion of carbon by the introduction of acetylene. This TiC does not grow continuously at the γ grain boundaries of SCM420, but grows granularly. The total carbon supply at 1050 ° C is 1.2 wt% on the SCM420 side of the TiC / SCM420 interface.

1100℃で浸炭されたTiC/SCM420は、850℃に再加熱され、再度アセチレンガスにより浸炭する。850℃での総炭素供給量は1050℃での供給量よりも少なく, TiC/SCM420界面のSCM420側で炭素濃度は1.4wt%である。この浸炭により粒内に球状炭化物を成長させる。この浸炭工程の中でN2ガスを導入し浸炭後に窒化し，油焼き入れ焼き戻す。油の温度は100℃, 焼き戻し温度は160℃である。 The TiC / SCM420 carburized at 1100 ° C. is reheated to 850 ° C. and carburized again with acetylene gas. The total carbon supply at 850 ° C is less than the supply at 1050 ° C, and the carbon concentration on the SCM420 side of the TiC / SCM420 interface is 1.4 wt%. By this carburizing, spherical carbides are grown in the grains. In this carburizing process, N2 gas is introduced, nitriding is performed after carburizing, and oil quenching and quenching are performed. The oil temperature is 100 ° C and the tempering temperature is 160 ° C.

上記工程で製造した構造材の組織は，表面から中心部にかけて深い方向に 層状炭化物/炭化物とマルテンサイト混合/パーライト/フェライトとパーライト混相となる。層状炭化物の厚さは図1の断面写真で確認できるように20μmである。マルテンサイトと球状炭化物の混相となっている部分前記層状炭化物と母材の界面から40-50μmまでの範囲である。この範囲ではTiの濃度勾配が認められる。表層部の炭素濃度は12〜17wt%であるが，マルテンサイトと炭化物の混相部では1.0-1.7wtとなり、炭化物を構成するTi濃度は減少する。Tiの濃度勾配はマルテンサイトと炭化物の混相部で1ｗｔ％/μmであり，濃度勾配は層状炭化物近傍ほど高くなる。 The structure of the structural material produced in the above process becomes a layered carbide / carbide mixed / martensite mixed / pearlite / ferrite and pearlite mixed phase in the deep direction from the surface to the center. The thickness of the layered carbide is 20 μm as can be confirmed in the cross-sectional photograph of FIG. Part of the mixed phase of martensite and spherical carbide The range is from the interface between the layered carbide and the base metal to 40-50 μm. A Ti concentration gradient is observed in this range. The carbon concentration in the surface layer is 12 to 17 wt%, but the carbon concentration in the mixed phase of martensite and carbide is 1.0-1.7 wt, and the Ti concentration constituting the carbide decreases. The concentration gradient of Ti is 1 wt% / μm at the mixed phase of martensite and carbide, and the concentration gradient becomes higher near the layered carbide.

炭化物を形成せずに浸炭焼き入れ焼き戻した場合と比較して、回転曲げ疲労試験による疲労寿命は本実施例では20倍となる。このような高疲労寿命となる要因を以下に示す。TiCやTiCNが表面に厚さ20μmで形成され、硬さは図２に示すようにお1550〜1800Hvである。このTiCやTiCN及びTiNOが図3に示すＸ線回折パターンで確認でき, 炭化物がSCM420に分散した領域がSCM420とTiC系膜の間に形成され，TiCやTiCNの密着性を高めている。粒状TiCの周囲にはマルテンサイト及び残留オーステナイトが形成され,マルテンサイトの硬さは750Hvである。粒状TiCは材料中心では認められず，Ti及び炭素の拡散によって成長したものであり、表面から中心部にかけてTiCの量は減少し，炭化物はTiC系よりもFe3C系であるセメンタイトが増加する。このような構成となるため，表層に摩耗しにくい高硬度のTiCあるいはTiCN系膜が成長していること、分散した高硬度TiCとその周囲の微細マルテンサイト、Fe3Cとその周囲のマルテンサイトによってき裂の発生及び伝搬が抑制されている。The fatigue life by the rotary bending fatigue test is 20 times longer in this example than in the case of carburizing, quenching and tempering without forming carbides. The factors that lead to such a high fatigue life are shown below. TiC and TiCN are formed on the surface with a thickness of 20 μm, and the hardness is 1550 to 1800 Hv as shown in FIG. The TiC, TiCN, and TiNO can be confirmed by the X-ray diffraction pattern shown in Fig. 3, and a region in which carbides are dispersed in the SCM420 is formed between the SCM420 and the TiC-based film, which enhances the adhesion of TiC and TiCN. Martensite and retained austenite are formed around the granular TiC, and the hardness of martensite is 750 Hv. Granular TiC is not found in the center of the material, but is grown by diffusion of Ti and carbon, the amount of TiC decreases from the surface to the center, and the carbides increase in cementite, which is Fe 3 C, rather than Ti C. .. Due to this structure, a high-hardness TiC or TiCN-based film that is not easily worn is growing on the surface layer, dispersed high-hardness TiC and its surrounding fine martensite, and Fe 3 C and its surrounding martensite. The generation and propagation of cracks are suppressed by this.

本実施例の断面模式図を図４に示す。母材であるSCM420の外側にMC炭化物を含む層が形成される。ＭＣ炭化物１の母材側にM3C炭化物とマルテンサイトの混相が形成される。図４には球状の形状を有するM3C炭化物３が見られ、マルテンサイト２に分散している。この混相のさらに内側（内部側）にパーライトが形成される。MC炭化物で表記されるMはTi, Nb, Ta, V, W , Moの少なくとも1種以上含有しており、M3CにもMC炭化物を構成するＭ元素が含有する。M3C炭化物中のＦｅはMC炭化物中のFeよりも高濃度である。A schematic cross-sectional view of this embodiment is shown in FIG. A layer containing MC carbide is formed on the outside of the base material SCM420. A mixed phase of M 3 C carbide and martensite is formed on the base metal side of MC carbide 1. In FIG. 4, M 3 C carbide 3 having a spherical shape can be seen and dispersed in martensite 2. Pearlite is formed further inside (inside) of this mixed phase. M represented by MC carbide contains at least one of Ti, Nb, Ta, V, W, and Mo, and M 3 C also contains M element constituting MC carbide. Fe in M 3 C carbide has a higher concentration than Fe in MC carbide.

1200MPaでの回転曲げ試験でマルテンサイトのみ表層に形成したSCM420試験片と比較すると破断する繰り返し数で、本実施例の試験片は50倍となった。このように疲労試験における寿命が延びることが確認でき、本実施例の処理工程及び材料構成は摺動材として高寿命が不可欠な部材に適用でき、特に自動車用トルク伝達部品や繰り返し稼働部、回転部などの部品に使用可能である。 Compared with the SCM420 test piece in which only martensite was formed on the surface layer in the rotary bending test at 1200 MPa, the number of repetitions of fracture was 50 times that of the test piece of this example. In this way, it can be confirmed that the life in the fatigue test is extended, and the processing process and material composition of this embodiment can be applied to members whose long life is indispensable as sliding materials, especially torque transmission parts for automobiles, repetitive moving parts, and rotation. It can be used for parts such as parts.

このような疲労寿命の向上はSCM420以外の鉄炭素系構造材に対しても図４の組織構成とすることにより達成できる。 Such an improvement in fatigue life can be achieved by adopting the structural structure shown in FIG. 4 for iron-carbon-based structural materials other than SCM420.

疲労試験の結果を図５に示す。ガス浸炭と比較して同じ疲労サイクルで面圧は1.3倍に増加する。また同一面圧で寿命が10倍以上増加する。このように疲労試験における寿命が延びることが確認でき、本実施例の処理工程及び材料構成は摺動材として高寿命が不可欠な部材に適用でき、特に自動車用トルク伝達部品や繰り返し稼働部、回転部などの部品に使用可能である。 The results of the fatigue test are shown in FIG. The surface pressure increases 1.3 times in the same fatigue cycle as compared to gas carburizing. In addition, the life is increased by 10 times or more at the same surface pressure. In this way, it can be confirmed that the life in the fatigue test is extended, and the processing process and material composition of this embodiment can be applied to members whose long life is indispensable as sliding materials, especially torque transmission parts for automobiles, repetitive moving parts, and rotation. It can be used for parts such as parts.

本実施形態では、最表面ではMC、マルテンサイトではM3Cが存在する。MCの方がM3Cよりも高硬度で耐摩耗性に優れるので、最表層にMCを必要とする。内部は炭素濃度を低くしてM3Cを分散させる。In this embodiment, MC is present on the outermost surface and M 3 C is present on martensite. MC requires MC on the outermost layer because it has higher hardness and better wear resistance than M 3 C. Inside, the carbon concentration is lowered to disperse M 3 C.

１…MC炭化物、２…マルテンサイト、３…M3C炭化物、４…パーライト1 ... MC carbide, 2 ... Martensite, 3 ... M 3 C carbide, 4 ... Pearlite

Claims (4)

鉄及び炭素を含有する構造材において、
中心から表面に向かって、パーライトで構成する第１層、マルテンサイト及び炭化物の混合相で構成する第２層、炭化物で構成する第３層を有し、
前記第３層の炭化物はMC（MはTi，V，Nb，Mo，Ta，Wの中の少なくとも１種の元素）で示され、
表面から中心に向かって、M元素濃度が減少する濃度勾配を有し、
前記第３層の炭素濃度が12〜17質量％であり、前記第２層の炭素濃度が1.0〜1.7質量％であることを特徴とする構造材。 In structural materials containing iron and carbon
From the center to the surface, it has a first layer composed of pearlite, a second layer composed of a mixed phase of martensite and carbides, and a third layer composed of carbides.
The carbide of the third layer is represented by MC (M is Ti, V, Nb, Mo, Ta, at least one element in W),
Toward the center from the surface have a concentration gradient M element concentration decreases,
A structural material characterized in that the carbon concentration of the third layer is 12 to 17% by mass and the carbon concentration of the second layer is 1.0 to 1.7% by mass . 請求項１に記載の構造材において、
前記第２層の炭化物はM3C（MはTi，V，Nb，Mo，Ta，Wの中の少なくとも１種の元素）で示され、
前記第２層ではマルテンサイトに球状の炭化物が分散して混合相を形成することを特徴とする構造材。 In the structural material according to claim 1,
The carbide of the second layer M 3 C (M is Ti, V, Nb, Mo, Ta, at least one element among W) is indicated by,
In the second layer, a structural material characterized in that spherical carbides are dispersed in martensite to form a mixed phase. 請求項１に記載の構造材において、
前記第３層に炭窒化物を含有することを特徴とする構造材。 In the structural material according to claim 1,
A structural material characterized by containing a carbonitride in the third layer. 請求項１に記載の構造材において、
前記第３層の硬さがビッカース硬さで1500〜3500の範囲であることを特徴とする構造材。 In the structural material according to claim 1,
A structural material characterized in that the hardness of the third layer is in the range of 1500 to 3500 in Vickers hardness.
JP2018550124A 2016-11-08 2017-10-25 Structural material Active JP6771580B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2016217728 2016-11-08
JP2016217728 2016-11-08
PCT/JP2017/038449 WO2018088207A1 (en) 2016-11-08 2017-10-25 Structural material

Publications (2)

Publication Number Publication Date
JPWO2018088207A1 JPWO2018088207A1 (en) 2019-06-24
JP6771580B2 true JP6771580B2 (en) 2020-10-21

Family

ID=62109685

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2018550124A Active JP6771580B2 (en) 2016-11-08 2017-10-25 Structural material

Country Status (3)

Country Link
US (1) US20190284676A1 (en)
JP (1) JP6771580B2 (en)
WO (1) WO2018088207A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019131868A (en) * 2018-02-01 2019-08-08 日立オートモティブシステムズ株式会社 Slide member

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6998265B2 (en) * 2018-04-27 2022-02-04 日立Astemo株式会社 Sliding member and its manufacturing method and power steering device and its manufacturing method
JPWO2022230937A1 (en) * 2021-04-28 2022-11-03

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58174567A (en) * 1982-04-02 1983-10-13 Toyota Central Res & Dev Lab Inc Method for coating metal material with carbide
HRP20000916B1 (en) * 2000-12-29 2005-06-30 Božidar Matijević Mladen Stupnišek Duplex process for diffusional creation of solid carbide layers on metal materials
JP4282298B2 (en) * 2002-10-09 2009-06-17 株式会社タンガロイ Super fine cemented carbide
JP5319866B2 (en) * 2004-05-24 2013-10-16 株式会社小松製作所 Rolling member and manufacturing method thereof
MY146096A (en) * 2005-08-02 2012-06-29 Honda Motor Co Ltd Layered fe-based alloy and method for producing the same
JP4904106B2 (en) * 2006-07-25 2012-03-28 Ｎｔｎ株式会社 Rolling parts

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019131868A (en) * 2018-02-01 2019-08-08 日立オートモティブシステムズ株式会社 Slide member
JP7015181B2 (en) 2018-02-01 2022-02-02 日立Astemo株式会社 Sliding member

Also Published As

Publication number Publication date
US20190284676A1 (en) 2019-09-19
JPWO2018088207A1 (en) 2019-06-24
WO2018088207A1 (en) 2018-05-17

Similar Documents

Publication Publication Date Title
JP5241455B2 (en) Carbonitriding member and method for producing carbonitriding member
JP4100751B2 (en) Rolling member and manufacturing method thereof
JP3413975B2 (en) Rolling bearing with excellent wear resistance
WO2011111269A1 (en) Carburized steel component having excellent low-cycle bending fatigue strength
JP6771580B2 (en) Structural material
JP4627776B2 (en) High concentration carburizing / low strain quenching member and method of manufacturing the same
WO2008056552A1 (en) Process for producing high-concentration carburized steel
WO2013121794A1 (en) Soft-nitriding steel and soft-nitrided component using steel as material
CN103097561A (en) Steel component having excellent temper softening resistance
JP2010163671A (en) Steel for soft nitriding
JP2005090680A (en) Rolling bearing part and method of manufacturing the same
JP2001073072A (en) Carbo-nitrided parts excellent in pitching resistance
JP4752635B2 (en) Method for manufacturing soft nitrided parts
JP2006348321A (en) Steel for nitriding treatment
JP2010222636A (en) Surface treatment method of steel product
JP2002030338A (en) High concentration carburizing and quenching method of steel, and high concentration carburizing and quenching parts
JP2000204464A (en) Surface treated gear, its production and producing device therefor
JP2004107709A (en) Rolling member and manufacturing method thereof
US7828910B2 (en) Method and process for thermochemical treatment of high-strength, high-toughness alloys
JPH0559527A (en) Production of steel excellent in wear resistance and rolling fatigue characteristic
JP2007063667A (en) LAYERED Fe-BASED ALLOY AND PROCESS FOR PRODUCTION THEREOF
JP7015181B2 (en) Sliding member
JPH10204534A (en) Track bushing and its production
JP2009007603A (en) Gear
WO2007015514A1 (en) LAYERED Fe-BASED ALLOY AND PROCESS FOR PRODUCTION THEREOF

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20190215

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20200303

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20200428

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20200908

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20200929

R150 Certificate of patent or registration of utility model

Ref document number: 6771580

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150