JP6259579B2 - High-strength stainless steel wire, high-strength spring, and method of manufacturing the same - Google Patents
High-strength stainless steel wire, high-strength spring, and method of manufacturing the same Download PDFInfo
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- 229910001220 stainless steel Inorganic materials 0.000 title claims description 80
- 238000004519 manufacturing process Methods 0.000 title claims description 22
- 238000010438 heat treatment Methods 0.000 claims description 75
- 230000032683 aging Effects 0.000 claims description 59
- 229910000831 Steel Inorganic materials 0.000 claims description 49
- 239000010959 steel Substances 0.000 claims description 49
- 229910000734 martensite Inorganic materials 0.000 claims description 44
- 238000012545 processing Methods 0.000 claims description 39
- 150000001875 compounds Chemical class 0.000 claims description 30
- 239000002245 particle Substances 0.000 claims description 22
- 238000012360 testing method Methods 0.000 claims description 14
- 229910000943 NiAl Inorganic materials 0.000 claims description 13
- NPXOKRUENSOPAO-UHFFFAOYSA-N Raney nickel Chemical compound [Al].[Ni] NPXOKRUENSOPAO-UHFFFAOYSA-N 0.000 claims description 13
- 239000011159 matrix material Substances 0.000 claims description 13
- 238000005482 strain hardening Methods 0.000 claims description 12
- 229910052782 aluminium Inorganic materials 0.000 claims description 9
- 229910052750 molybdenum Inorganic materials 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 7
- 238000005336 cracking Methods 0.000 claims description 6
- 230000007613 environmental effect Effects 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 3
- 229910052758 niobium Inorganic materials 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 238000007665 sagging Methods 0.000 claims 1
- 239000000047 product Substances 0.000 description 28
- 238000000034 method Methods 0.000 description 23
- 239000000463 material Substances 0.000 description 19
- 238000005491 wire drawing Methods 0.000 description 19
- 239000010935 stainless steel Substances 0.000 description 15
- 230000000694 effects Effects 0.000 description 11
- 230000008569 process Effects 0.000 description 10
- 238000005096 rolling process Methods 0.000 description 10
- 230000006835 compression Effects 0.000 description 9
- 238000007906 compression Methods 0.000 description 9
- 238000004881 precipitation hardening Methods 0.000 description 9
- 208000010392 Bone Fractures Diseases 0.000 description 8
- 230000001965 increasing effect Effects 0.000 description 8
- 238000001556 precipitation Methods 0.000 description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 7
- 239000000243 solution Substances 0.000 description 7
- 230000035882 stress Effects 0.000 description 7
- 239000002344 surface layer Substances 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 6
- 238000005260 corrosion Methods 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000000470 constituent Substances 0.000 description 4
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 238000010622 cold drawing Methods 0.000 description 3
- 238000005097 cold rolling Methods 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 230000001376 precipitating effect Effects 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009998 heat setting Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910001111 Fine metal Inorganic materials 0.000 description 1
- 208000025599 Heat Stress disease Diseases 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 238000005242 forging Methods 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 238000001192 hot extrusion Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 239000010410 layer Substances 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 229910001105 martensitic stainless steel Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 239000000344 soap Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C1/00—Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
- B21C1/003—Drawing materials of special alloys so far as the composition of the alloy requires or permits special drawing methods or sequences
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
- C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
-
- 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
- C22C38/002—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
- C22C38/02—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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- 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
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- 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
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- 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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
- C22C38/40—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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/04—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of bars or wire
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Description
本発明は自動車エンジン排気系部品や電装部品等の耐熱性とともに高強度特性が要求される部品、主に耐熱ばね用,耐熱ロープ用など耐熱鋼線材料として使用される高強度ステンレス鋼線に関する。本発明は、オーステナイト(γ)相+加工誘起マルテンサイト(α‘)相の金属組織を有しMo,Al等を添加して冷間加工と時効熱処理により微細析出物を制御した析出硬化型準安定オーステナイト系の高強度ステンレス鋼線、特に高強度耐熱ステンレス鋼線と、これを用いた高強度ばね、特に高強度耐熱ばね並びにその製造方法に関する。 The present invention relates to a high-strength stainless steel wire that is used as a heat-resistant steel wire material such as a heat-resistant spring or a heat-resistant rope, such as an automobile engine exhaust system component or an electrical component that requires high strength characteristics. The present invention is a precipitation hardening quasi-type that has a metal structure of an austenite (γ) phase + work-induced martensite (α ′) phase and that has fine precipitates controlled by cold working and aging heat treatment by adding Mo, Al, etc. The present invention relates to a stable austenitic high-strength stainless steel wire, particularly a high-strength heat-resistant stainless steel wire, a high-strength spring using the same, particularly a high-strength heat-resistant spring, and a method for producing the same.
従来、高強度ばね用材料として、ピアノ線をはじめSUS304,SUS301などの高強度ステンレス鋼線が使用されてきた。しかし、従来のばね製品は、常温状態では十分な強度を有するものの、例えばピアノ線では環境温度が100℃〜300℃程度の温間域において耐熱へたり性が後述する残留剪断歪みで0.01%以上と急激に低下し、用途的な制限を受けるものであった。その傾向はステンレス鋼線による場合も同様であり、そのために、例えばMo,Al,Ti等を添加したオーステナイト系ステンレス鋼線が提案されている(特許文献1、2)。そうした成分調整によって、耐熱へたり性は改善するものの、逆に加工誘起マルテンサイト量が少なく、引張強さが1800MPa未満と強度不足となり、高強度ばね用製品として十分なものとは言い難い。 Conventionally, high strength stainless steel wires such as piano wire, SUS304, SUS301, etc. have been used as high strength spring materials. However, although the conventional spring product has sufficient strength at normal temperature, for example, in the case of a piano wire, the heat resistance sagability is 0.01 in terms of residual shear strain, which will be described later, in the warm temperature range of about 100 ° C. to 300 ° C. % Was drastically reduced to more than% and was subject to application restrictions. This tendency is the same when stainless steel wires are used. For this reason, for example, austenitic stainless steel wires to which Mo, Al, Ti, etc. are added have been proposed (Patent Documents 1 and 2). Although the heat sagability is improved by such component adjustment, conversely, the amount of work-induced martensite is small, the tensile strength is less than 1800 MPa, and the strength is insufficient, which is not sufficient as a product for high-strength springs.
また、Mo,Al等の析出硬化を利用したマルテンサイト系ステンレス鋼も提案されている(特許文献3)。しかしながら、このステンレス鋼はCが高く、熱処理後に既にマルテンサイト生地であるため加工性に劣り、また、大きな加工硬化が期待できず高強度ばね製品としては十分でない。 A martensitic stainless steel using precipitation hardening of Mo, Al, etc. has also been proposed (Patent Document 3). However, this stainless steel has a high C and is already martensitic after heat treatment, so it is inferior in workability, and cannot be expected to have a large work hardening, and is not sufficient as a high-strength spring product.
更に、Mo,Al,Cu等の析出硬化を利用した高強度の析出硬化型オーステナイト鋼が提案されている(特許文献4)。しかしながら、このステンレス鋼では、多量のNi,Cuを含有するので材料コストが高価である。また、このステンレス鋼は、加工誘起マルテンサイトを抑制しており、耐熱へたり性についても満足し難い。 Furthermore, a high strength precipitation hardening austenitic steel using precipitation hardening of Mo, Al, Cu, etc. has been proposed (Patent Document 4). However, since this stainless steel contains a large amount of Ni and Cu, the material cost is high. Further, this stainless steel suppresses work-induced martensite, and it is difficult to satisfy heat sagability.
このように、従来の高強度ばね用ステンレス鋼線では強度と耐熱へたり性を兼ね備えることができない。 Thus, conventional high-strength stainless steel wires for springs cannot have both strength and heat resistance.
本発明の解決すべき課題は、特に前記温間域で多用される耐熱材料、特に耐熱ばね用を前提として、その温度環境下でも十分な高強度特性及び耐熱へたり性を併せ持つ高強度ステンレス鋼線と、該鋼線による高強度ばね、並びにその製造方法を提供することである。 The problem to be solved by the present invention is a high-strength stainless steel that has sufficient high-strength characteristics and heat-resisting properties even under the temperature environment, especially on the premise of heat-resistant materials that are frequently used in the warm region, especially for heat-resistant springs. It is to provide a wire, a high-strength spring using the steel wire, and a manufacturing method thereof.
上記課題を解決するために種々検討した結果、析出硬化型の準安定オーステナイト系ステンレス鋼線において、
1)オーステナイト安定度を制御し、ばね形状などに成形加工する前に、冷間伸線などの強加工によりオーステナイト主体の組織から加工誘起マルテンサイト(オースフォームドマルテンサイト)組織を多量に形成することで、延性を保ちつつ強度を向上させること、
2)0.05≦(C+N)≦0.13の範囲に制御することで強度を保ちつつ延性を確保すること、
3)Al,Moを添加し、強加工と時効熱処理条件の組み合わせで、特に鋼線表層近傍の強加工された加工誘起マルテンサイト組織中にNiAl,Mo系の微細化合物を均一分散させること
で更に強度と耐熱へたり性を大幅に高めることが有効との結論に達し、本発明を得た。
As a result of various studies to solve the above problems, in the precipitation hardening type metastable austenitic stainless steel wire,
1) Control the austenite stability and form a large amount of work-induced martensite (ausformed martensite) structure from austenite-based structure by strong working such as cold drawing before forming into a spring shape. Improving strength while maintaining ductility,
2) Ensuring ductility while maintaining strength by controlling in the range of 0.05 ≦ (C + N) ≦ 0.13,
3) Addition of Al and Mo, and by further dispersing NiAl and Mo-based fine compounds uniformly in the strongly-worked work-induced martensite structure near the steel wire surface layer by a combination of strong working and aging heat treatment conditions The conclusion was reached that it was effective to significantly increase the strength and heat sagability, and the present invention was obtained.
すなわち、本発明は下記の構成を有する。
(1)質量%で、C:0.02〜0.12%,およびN:0.005〜0.03%を含み、かつ0.050%≦(C+N)≦0.13%で、Si:0.1〜2.0%,Mn:0.1〜2.0%,Ni:6.8〜9.0%,Cr:12.0〜14.4%,Mo:1.0〜3.0%,及びAl:0.5〜2.0%を含有し、残部Feおよび不可避的不純物で構成された時効熱処理が施されることにより優れた耐熱へたり性が得られる高強度ステンレス鋼線であり、
(1)式で表される加工誘起マルテンサイト生成指数MdS値が15〜60であり、且つ、マトリックス中の加工誘起マルテンサイト量が80〜99vol.%で、引張強さ1800〜2200MPaを備えることを特徴とする高強度ステンレス鋼線。
MdS=551−462(C+N)−9.2Si−8.1Mn−29(Ni+Cu)−13.7Cr−18.5Mo…(1)
但し、式中の元素記号は、当該元素の含有量(質量%)を意味する。
(2)質量%で、更にV:0.01〜1.0%,Nb:0.01〜1.0%,Ti:0.01〜1.0%,W:0.05〜2.0%,Ta:0.05〜2.0%のうち、1種類以上を含有することを特徴とする前記(1)に記載の高強度ステンレス鋼線。
(3)質量%で、更にCu:0.8%以下、Co:0.1〜2.0%、B:0.0005〜0.015%のうち、1種以上を含有することを特徴とする前記(1)又は(2)に記載の高強度ステンレス鋼線。
(4)質量%で、更にCa:0.0005〜0.01%,Mg:0.0005〜0.01%,REM:0.0005〜0.1%のうち、1種類以上を含有することを特徴とする前記(1)〜(3)のいずれかに記載の高強度ステンレス鋼線。
(5)該ステンレス鋼線を、その等価線径の100倍長さの標点距離間で保持し、その一端側を捻り回転する捻り試験したときの、縦割れなく破断に至る捻回値が5回以上の高捻回特性を有するものである、前記(1)〜(4)のいずれかに記載の高強度ステンレス鋼線。
(6)前記(1)〜(4)の何れかに記載の成分組成、加工誘起マルテンサイト量、及びMdS値を満足し、引張強さが2100〜2600MPaであり、粒径50nm以下のNiAl系の微細化合物粒子を備えることを特徴とする高強度ステンレス鋼線。
(7)引張強さ(σB)とその0.2%耐力(σ0.2)との耐力比{(σ0.2/σB)×100}が80〜95%で、耐熱ばね用途に用いられるものである前記(1)〜(5)のいずれかに記載の高強度ステンレス鋼線。
(8)引張強さ(σ B )とその0.2%耐力(σ 0.2 )との耐力比{(σ 0.2 /σ B )×100}が80〜95%で、耐熱ばね用途に用いられるものである(6)に記載の高強度ステンレス鋼線。
(9)前記(6)に記載のステンレス鋼線で構成され、環境温度200℃における(2)式で表される残留剪断ひずみがε≦0.008%であり、鋼線のマトリックスに、粒径50nm以下のNiAl系の微細化合物粒子を備えることを特徴とする耐熱へたり性に優れた高強度ばね。
残留剪断ひずみε={8ΔPD/πd3G}×100…(2)
但し、ΔP:荷重損失(N)、D:ばねの中心径(mm)、d:鋼線の等価線径(mm)、G:鋼線の横弾性係数(N/mm2)
(10)固溶化熱処理後に、所定の等価線径に総加工率で60〜90%の冷間加工を行うことにより製造した前記(1)〜(5)、(7)のいずれかに記載のステンレス鋼線を、所定のばね形状に成形処理した後、更に温度300〜600℃で時効熱処理を施すことにより、鋼線のマトリックス中に、粒径50nm以下のNiAl系の微細化合物粒子を析出させ、環境温度200℃における(2)式で表される残留剪断ひずみがε≦0.008%である高強度ばねを製造することを特徴とする耐熱へたり性に優れた高強度ばねの製造方法。
残留剪断ひずみε={8ΔPD/πd3G}×100…(2)
但し、ΔP:荷重損失(N)、D:ばねの中心径(mm)、d:鋼線の等価線径(mm)、G:鋼線の横弾性係数(N/mm2)
(11)次式(3)の時効熱処理因子が100〜10000での前記時効熱処理を施すことを特徴とする(10)に記載の耐熱へたり性に優れた高強度ばねの製造方法。
時効熱処理因子={温度(℃)×処理時間(min)}/2√{ばねの等価線径(mm)×展開長さ(mm)}・・・(3)
That is, the present invention has the following configuration.
(1) In mass%, C: 0.02 to 0.12%, and N: 0.005 to 0.03%, and 0.050% ≦ (C + N) ≦ 0.13%, Si: 0.1 to 2.0%, Mn: 0.1 to 2.0%, Ni: 6.8 to 9.0%, Cr: 12.0 to 14.4%, Mo: 1.0 to 3. High-strength stainless steel wire containing 0% and Al: 0.5-2.0%, and having excellent heat sag due to aging heat treatment composed of the balance Fe and unavoidable impurities And
The processing induced martensite generation index MdS value represented by the formula (1) is 15 to 60, and the processing induced martensite amount in the matrix is 80 to 99 vol. %, A high-strength stainless steel wire having a tensile strength of 1800-2200 MPa.
MdS = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (1)
However, the element symbol in a formula means content (mass%) of the said element.
(2) By mass%, V: 0.01 to 1.0%, Nb: 0.01 to 1.0%, Ti: 0.01 to 1.0%, W: 0.05 to 2.0 %, Ta: 0.05% to 2.0%, containing at least one kind, high strength stainless steel wire according to (1) above.
(3) It is characterized by containing at least one of Cu: 0.8% or less, Co: 0.1-2.0%, B: 0.0005-0.015% by mass%. The high-strength stainless steel wire according to (1) or (2).
(4) By mass%, further containing at least one of Ca: 0.0005 to 0.01%, Mg: 0.0005 to 0.01%, REM: 0.0005 to 0.1% The high-strength stainless steel wire according to any one of (1) to (3) above.
(5) When the stainless steel wire is held for a distance of 100 times as long as its equivalent wire diameter, and a torsion test in which one end of the stainless steel wire is twisted and rotated, the twist value that leads to breakage without vertical cracking is The high-strength stainless steel wire according to any one of (1) to (4), which has a high twisting characteristic of 5 times or more.
(6) the (1) chemical composition, strain-induced martensite amount of any one of - (4), and satisfies the MdS value, tensile strength Ri 2100~2600MPa der, particle size 50nm following NiAl A high-strength stainless steel wire characterized by comprising fine compound particles of the system .
(7) The yield strength ratio {(σ 0.2 / σ B ) × 100} between the tensile strength (σ B ) and its 0.2% yield strength (σ 0.2 ) is 80 to 95%, and is used for a heat resistant spring. The high-strength stainless steel wire according to any one of the above (1) to ( 5 ), which is used in the manufacturing process.
(8) The strength ratio {(σ 0.2 / σ B ) × 100} between the tensile strength (σ B ) and its 0.2% yield strength (σ 0.2 ) is 80 to 95%, and is used for heat resistant springs The high-strength stainless steel wire according to (6).
( 9 ) The stainless steel wire according to the above (6), the residual shear strain represented by the formula (2) at an environmental temperature of 200 ° C. is ε ≦ 0.008%. A high-strength spring excellent in heat sag resistance, comprising NiAl fine compound particles having a diameter of 50 nm or less.
Residual shear strain ε = {8ΔPD / πd 3 G} × 100 (2)
Where ΔP: load loss (N), D: center diameter of spring (mm), d: equivalent wire diameter of steel wire (mm), G: transverse elastic modulus of steel wire (N / mm 2 )
( 10 ) The manufacturing method according to any one of (1) to (5) and (7) , wherein the processing is performed by performing 60 to 90% cold working on a predetermined equivalent wire diameter after a solution heat treatment. After the stainless steel wire is formed into a predetermined spring shape, it is further subjected to an aging heat treatment at a temperature of 300 to 600 ° C. to precipitate NiAl-based fine compound particles having a particle size of 50 nm or less in the steel wire matrix. A method for producing a high-strength spring with excellent heat resistance, characterized in that a high-strength spring having a residual shear strain represented by the formula (2) at an environmental temperature of 200 ° C. is ε ≦ 0.008% .
Residual shear strain ε = {8ΔPD / πd 3 G} × 100 (2)
Where ΔP: load loss (N), D: center diameter of spring (mm), d: equivalent wire diameter of steel wire (mm), G: transverse elastic modulus of steel wire (N / mm 2 )
(11) the following equation (3) high-strength spring manufacturing method having excellent heat fatigue resistance according to aging heat treatment factors and characterized by applying the aging heat treatment at 100 to 10000 (10).
Aging heat treatment factor = {temperature (° C.) × treatment time (min)} / 2√ {equivalent wire diameter of spring (mm) × deployed length (mm)} (3)
本発明の耐熱へたり性に優れた析出硬化型の高強度ステンレス鋼線は、その伸線加工段階で高い加工誘起マルテンサイト(α‘)量と所定の引張強さを有するものとなる。また、本発明の高強度ステンレス鋼線は、ばね形状に成形処理した後、時効熱処理を施すことで、微細化合物の形成、特に鋼線表層に均一分散する微細化合物の析出を促進して、更に高強度且つ特に温間域での耐熱へたり性を付与することができる。これにより、従来、両立が困難であった高強度かつ優れた耐熱へたり性を有する高強度ばね製品を提供することができる。したがって、本発明の高強度ステンレス鋼線は、特に厳しい品質特性が求められる高強度ばね用に好適である。 The precipitation hardening type high-strength stainless steel wire excellent in heat sag resistance according to the present invention has a high work-induced martensite (α ′) amount and a predetermined tensile strength at the wire drawing stage. In addition, the high-strength stainless steel wire of the present invention is formed into a spring shape and then subjected to an aging heat treatment to promote formation of fine compounds, particularly precipitation of fine compounds uniformly dispersed in the steel wire surface layer. It is possible to impart high strength and heat sagability particularly in a warm region. As a result, it is possible to provide a high-strength spring product having high strength and excellent heat sagability that has been difficult to achieve at the same time. Therefore, the high-strength stainless steel wire of the present invention is suitable for high-strength springs that require particularly strict quality characteristics.
また、ばねの製造方法の発明によれば、通常の低温熱処理の範囲内で実施でき、連続化によって特別なコストアップを伴うことなく安定的に実施できる。 In addition, according to the invention of the spring manufacturing method, it can be carried out within the range of normal low-temperature heat treatment, and can be carried out stably without any special cost increase due to continuation.
前記記載のように本発明のステンレス鋼線は、
質量%で、C:0.02〜0.12%,およびN:0.005〜0.03%を含み、かつ0.05%≦(C+N)≦0.13%で、Si:0.1〜2.0%,Mn:0.1〜2.0%,Ni:6.8〜9.0%,Cr:12.0〜14.4%,Mo:1.0〜3.0%,及びAl:0.5〜2.0%を含有し、残部Feおよび不可避的不純物で構成され、(1)式で表される加工誘起マルテンサイト(α‘)生成指数(以下、単に「生成指数」という)MdS値が15〜60であり、
そのマトリックス中に80〜99vol.%の加工誘起α’量を含み、かつ引張強さ1800〜2200MPaを備えることを特徴とする耐熱へたり性に優れた高強度ステンレス鋼線である。本発明の高強度ステンレス鋼線は、特に高強度耐熱ステンレス鋼線として、例えばばね用の線材、特に環境温度が100〜300℃の温間域での使用に好適するものである。
As described above, the stainless steel wire of the present invention is
% By mass, C: 0.02 to 0.12%, and N: 0.005 to 0.03%, and 0.05% ≦ (C + N) ≦ 0.13%, Si: 0.1 -2.0%, Mn: 0.1-2.0%, Ni: 6.8-9.0%, Cr: 12.0-14.4%, Mo: 1.0-3.0%, And Al: 0.5 to 2.0%, composed of the balance Fe and inevitable impurities, and a processing-induced martensite (α ′) production index represented by the formula (1) (hereinafter simply referred to as “production index”) The MdS value is 15-60,
In the matrix, 80-99 vol. It is a high-strength stainless steel wire excellent in heat sag resistance, characterized in that it contains a processing-induced α ′ amount of 1% and has a tensile strength of 1800-2200 MPa. The high-strength stainless steel wire of the present invention is particularly suitable as a high-strength heat-resistant stainless steel wire, for example, for use in a spring wire, particularly in a warm region where the environmental temperature is 100 to 300 ° C.
MdS=551−462(C+N)−9.2Si−8.1Mn−29(Ni+Cu)−13.7Cr−18.5Mo…(1)
但し、式中の元素記号は、当該元素の含有量(質量%)を意味する。また、計算に必要な元素が含まれていない、又は、その含有量が不明である元素については、その元素の含有量として0を代入するものとする。
MdS = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (1)
However, the element symbol in a formula means content (mass%) of the said element. In addition, for an element that does not contain an element necessary for the calculation or whose content is unknown, 0 is substituted as the content of the element.
その形態は特に制限するものではなく、通常の線材として例えば線径6mm以下、より具体的には0.05〜3mm程度の2次加工用の細線用途に多用され、また、その形状も丸線以外に、例えば平線や角線等の非円形形状の線材として用い得る。しかし、これに限るものではなく、種々形態で応用可能である。このように、本発明のステンレス鋼線はその断面形状が非円形形状の線材をも含むことから、その場合の線径表示は、例えばその任意の横断面面積から算出される等価線径(d)によるものとする。
なお、本形態では前記丸線を対象として伸線加工による場合を中心に説明するが、これに代えて、例えば圧延加工乃至前記伸線加工と組み合わせる複合加工を採用し得る。
The form is not particularly limited, and for example, it is frequently used as a thin wire for secondary processing of, for example, a wire diameter of 6 mm or less, more specifically about 0.05 to 3 mm as a normal wire, and the shape is also a round wire. In addition, for example, it can be used as a non-circular wire such as a flat wire or a square wire. However, the present invention is not limited to this and can be applied in various forms. As described above, since the stainless steel wire of the present invention also includes a wire having a non-circular cross-sectional shape, the wire diameter display in that case is, for example, an equivalent wire diameter (d calculated from its arbitrary cross-sectional area) (d ).
In this embodiment, the description will be focused on the case where the round wire is used as a target, but instead of this, for example, a rolling process or a combined process combined with the wire drawing process may be employed.
また、ステンレス鋼線は、最終段階で行われる時効熱処理によって、そのマトリックス中に微細な化合物粒子を析出分布する析出硬化機能を備えている。本発明では、析出硬化機能を発揮するように、その組成にAl及びMo等の析出元素を加え、N及びCを適量に添加している。そして、冷間伸線や冷間圧延等の引抜加工条件によって強加工された鋼線表層近傍の加工誘起マルテンサイト相にNiAl,Mo系の化合物粒子を均一に分散して析出させることで、高強度で且つ耐熱へたり性に優れた高強度の耐熱ばね製品の提供を可能にしている。 Further, the stainless steel wire has a precipitation hardening function for precipitating and distributing fine compound particles in the matrix by aging heat treatment performed in the final stage. In the present invention, precipitation elements such as Al and Mo are added to the composition so that the precipitation hardening function is exhibited, and N and C are added in appropriate amounts. By uniformly dispersing and precipitating NiAl, Mo-based compound particles in the work-induced martensite phase in the vicinity of the steel wire surface layer that has been strongly processed under the drawing conditions such as cold drawing and cold rolling, This makes it possible to provide high-strength heat-resistant spring products that are strong and have excellent heat resistance.
一般的にオーステナイト系ステンレス鋼は、その冷間加工によって加工硬化することは周知であり、その要因の一つに、加工に伴って誘起する加工誘起マルテンサイト相の影響がある。しかし、その誘起発生量は、これを構成する各元素の成分組成のバランスとその加工条件によって大きく異なる。例えば、安定型のSUS316系ステンレス鋼では通常の加工処理を行っても、誘起マルテンサイトの生成量はわずか数%程度に留まる。これに対し、本発明では、冷間加工に伴う加工誘起マルテンサイトの生成を積極的に促進して、その生成量を80〜99vol%に高めるように調整し、鋼線自体の引張強さを伸線等の冷間加工状態で1800〜2200MPaに高強度化することを特徴の一つにしている。 In general, it is well known that austenitic stainless steel is work-hardened by cold working, and one of the factors is the influence of work-induced martensite phase induced by working. However, the amount of induced generation varies greatly depending on the balance of the component composition of each element constituting this and the processing conditions. For example, with a stable SUS316 stainless steel, the amount of induced martensite produced is only a few percent even when normal processing is performed. On the other hand, in the present invention, the production of martensite induced by cold working is actively promoted, the production amount is adjusted to be increased to 80 to 99 vol%, and the tensile strength of the steel wire itself is adjusted. One of the features is that the strength is increased to 1800 to 2200 MPa in a cold working state such as wire drawing.
そして、その高強度特性とともにばね製品での耐熱へたり性を改善する更なる手段として、微細析出物の析出核となる前記加工誘起マルテンサイト量の生成が促進されるように、各成分組成のバランスの指標として前記生成指数MdS値が15〜60になるように調整したステンレス鋼を特定の加工条件で伸線加工することとしている。
なお、MdS値は、ステンレス鋼に30%の引張変形を与えたときに組織の50%がマルテンサイト相に変態する温度を意味し、加工に伴って生成される加工誘起マルテンサイト量のレベルを成分元素との関係で把握するものである。
And as a further means of improving the heat-resistant sagability in the spring product together with its high strength characteristics, the composition of each component is set so as to promote the production of the amount of work-induced martensite that becomes the precipitation nuclei of fine precipitates. Stainless steel adjusted so that the generation index MdS value is 15 to 60 is drawn as a balance index under specific processing conditions.
The MdS value means a temperature at which 50% of the structure is transformed into a martensite phase when 30% tensile deformation is applied to the stainless steel. This is to be grasped in relation to the component elements.
これによって、伸線加工時の加工誘起マルテンサイト量を高めることができ、高強度化に寄与する。 Thereby, the amount of work-induced martensite at the time of wire drawing can be increased, which contributes to higher strength.
本発明で前記MdS値を前記範囲に設定する理由は、MdS値が15未満のものでは、オーステナイト相の安定化が増し、伸線加工後の加工誘起マルテンサイト量が80vol%未満と低くなり、高強度化しにくくなるばかりでなく、300〜600℃での時効熱処理に伴う析出強化量も低減して、耐熱へたり性も劣化する。一方、MdS値が60を超えるものでは、所定の伸線加工で99vol%を超える余剰の加工誘起マルテンサイトが生成され、伸線後の延靭性が低下して、製造性が劣る。より好ましくはMdS値の範囲を20〜50とする。 The reason why the MdS value is set in the above range in the present invention is that when the MdS value is less than 15, the stabilization of the austenite phase increases, and the amount of work-induced martensite after wire drawing decreases to less than 80 vol%, Not only does it become difficult to increase the strength, but the amount of precipitation strengthening associated with the aging heat treatment at 300 to 600 ° C. is also reduced, and the heat sagability is also deteriorated. On the other hand, when the MdS value exceeds 60, excess work-induced martensite exceeding 99 vol% is generated by a predetermined wire drawing process, the toughness after wire drawing is lowered, and the productivity is inferior. More preferably, the range of the MdS value is 20-50.
こうした成分調整によって、本発明のステンレス鋼線は加工誘起マルテンサイト量80〜99vol%を可能とし、各特性向上が図られる。すなわち、マトリックス中の加工誘起α’(マルテンサイト)の分量が80vol%未満のものでは、ばね製品において時効熱処理を行っても必要な高強度特性が得られず、逆に99vol%を超えるものでは組織的安定性を欠いて耐食性や靭性が満足し難い。また耐ばね疲労性に劣ることも予想される。加工誘起マルテンサイト量は、好ましくは83vol%以上であり、85vol%以上であることがより好ましい。また、加工誘起マルテンサイト量は95vol%以下であることが好ましく、より好ましくは90vol%以下の範囲とする。 By adjusting the components as described above, the stainless steel wire of the present invention can achieve a work-induced martensite amount of 80 to 99 vol%, and each characteristic can be improved. In other words, if the amount of processing-induced α ′ (martensite) in the matrix is less than 80 vol%, the necessary high strength characteristics cannot be obtained even if aging heat treatment is performed on the spring product, and conversely if it exceeds 99 vol%. Lack of organizational stability and hardly satisfy corrosion resistance and toughness. It is also expected to be inferior in spring fatigue resistance. The amount of processing-induced martensite is preferably 83 vol% or more, and more preferably 85 vol% or more. Further, the processing induced martensite amount is preferably 95 vol% or less, more preferably 90 vol% or less.
[マルテンサイト量の計測]
また該マルテンサイト量の計測は、ステンレス鋼線から任意に採取した試験片に対して、例えばフェライトスコープによる方法、磁気法やX線による方法など種々方法が採用可能であり、例えば後者の磁気法などについては、例えば日本鉄鋼協会「鉄と鋼」(81−S1163)他にも多々説明されている。
[Measurement of martensite content]
For the measurement of the amount of martensite, various methods such as a method using a ferrite scope, a magnetic method, and a method using X-rays can be employed for a specimen arbitrarily collected from a stainless steel wire. For example, the latter magnetic method For example, the Japan Iron and Steel Institute “Iron and Steel” (81-S1163) and many others are described.
本発明では、加工誘起α’量は直流磁束計にて線材の1.0×104Oeでの飽和磁化値を測定し、下記の(4)〜(6)式を用いて算出した。
加工誘起α’量(vol.%)=σs/σs(bcc)×100…(4)
σs:飽和磁化値(T),σs(bcc):100%α’変態した時の飽和磁化値(計算値)
σs(bcc)=1.83−0.030Creq…(5)
Creq=Cr+1.8Si+Mo+0.5Ni+0.9Mn+3.6(C+N)+1.25P+2.91S+1.85Al…(6)
In the present invention, the processing-induced α ′ amount was calculated using the following equations (4) to (6) after measuring the saturation magnetization value of the wire at 1.0 × 10 4 Oe with a DC magnetometer.
Processing-induced α ′ amount (vol.%) = Σ s / σ s (bcc) × 100 (4)
σ s : Saturation magnetization value (T), σ s (bcc): 100% α ′ transformation saturation magnetization value (calculated value)
σ s (bcc) = 1.83-0.030Cr eq (5)
Cr eq = Cr + 1.8Si + Mo + 0.5Ni + 0.9Mn + 3.6 (C + N) + 1.25P + 2.91S + 1.85Al (6)
こうしてステンレス鋼線は、その冷間伸線加工された状態での引張強さ(σB)が1800〜2200MPaの高強度特性を有するものとしている。引張強さは、例えばJIS−Z2241により計測可能であり、その特性が1800MPa未満のものでは、その後の時効熱処理によっても強度特性の大幅向上が見込めず、また2200MPaを超える程高くしたものでは、ばね成形加工段階でばね形状のバラツキを増大したり、脆性破壊を誘発しやすいなど品質面で問題がある。より好ましい引張強さは、1900〜2100MPaである。 Thus, the stainless steel wire has a high strength characteristic in which the tensile strength (σ B ) in the cold drawn state is 1800 to 2200 MPa. The tensile strength can be measured, for example, according to JIS-Z2241, and if the property is less than 1800 MPa, the strength property cannot be significantly improved even by subsequent aging heat treatment, and if the strength is increased to exceed 2200 MPa, the spring There are problems in terms of quality, such as increasing the variation of the spring shape at the molding stage and easily inducing brittle fracture. More preferable tensile strength is 1900-2100 MPa.
一方、本発明の冷間伸線加工された該鋼線に、時効熱処理を施すと強度特性が更に、飛躍的に向上し、時効熱処理の条件によっては引張強さ2100〜2600MPaという好ましい値が得られる。したがって、例えばばね形状品がマイクロシャフト用などのように、直線状態で使用する用途にあっては、前記伸線加工に続いて矯正処理し、これをそのまま連続時効熱処理して長尺のばね材料とすることもできる。このことで、ワイヤー状態での機械的特性を更に高めることができる。なお、これら処理は連続的に行うことができる。
本発明は冷間伸線加工後に時効熱処理したステンレス鋼線についても他の形態として含むものとしている。その場合の引張強さは2100〜2600MPaであり、より好ましい引張強さの下限は2200MPaであり、より好ましい上限は2500MPaである。なお、鋼線に対する時効熱処理条件は、時効熱処理後の引張強さが上記範囲になるように適宜設定することができるが、一例として後述するようにばね成形後の時効熱処理条件を挙げることができる。
On the other hand, when the steel wire that has been cold-drawn according to the present invention is subjected to an aging heat treatment, the strength characteristics are further improved dramatically, and a preferable value of 2100 to 2600 MPa in tensile strength is obtained depending on the conditions of the aging heat treatment. It is done. Therefore, for applications where the spring-shaped product is used in a straight state, such as for a microshaft, a straight spring treatment is performed following the wire drawing process, and this is subjected to continuous aging heat treatment as it is to provide a long spring material. It can also be. This can further enhance the mechanical properties in the wire state. In addition, these processes can be performed continuously.
The present invention includes other forms of stainless steel wire that has been subjected to aging heat treatment after cold drawing. The tensile strength in that case is 2100-2600 MPa, the more preferable lower limit of tensile strength is 2200 MPa, and the more preferable upper limit is 2500 MPa. The aging heat treatment conditions for the steel wire can be set as appropriate so that the tensile strength after the aging heat treatment is in the above range, but as an example, aging heat treatment conditions after spring forming can be mentioned as described later. .
また、引張強さ(σB)とともに求められる0.2%耐力(σ0.2)との耐力比{(σ0.2/σB)×100}が80〜95%であることが好ましい。このようなステンレス鋼線は、高強度かつ疲労破断を改善する耐熱ばね用材料として有効である。なお、この耐力比が80%未満では所定の弾性特性が得られず、95%を超えるものでは、過酷なばね加工の際の歩留りに悪影響を及ぼす恐れがある。耐力比のより好ましい下限は83%であり、より好ましい上限は91%である。 Further, the yield strength ratio {(σ 0.2 / σ B ) × 100} to the 0.2% yield strength (σ 0.2 ) obtained together with the tensile strength (σ B ) is preferably 80 to 95%. Such a stainless steel wire is effective as a heat-resistant spring material that has high strength and improves fatigue fracture. If the yield ratio is less than 80%, the predetermined elastic characteristics cannot be obtained, and if it exceeds 95%, the yield during severe spring processing may be adversely affected. A more preferable lower limit of the yield strength ratio is 83%, and a more preferable upper limit is 91%.
[捻り試験1]
また、ばね加工性を評価する他の試験方法として、次の捻り試験による捻回特性で行うこともできる。捻回特性は、該ステンレス鋼線から採取した試験片を、その等価線径の100倍長さの標点距離間で保持して、その一端側を捻り回転することで破断するまでの回数で示され、例えば、冷間加工されたステンレス鋼線では、その捻り回数(捻回値)が縦割れ無く5回以上、例えば5〜10回程度以上の高捻回特性を有するものであるならば、種々ばね製品に対して広く用いることができる。そしてそのような時効熱処理が施された鋼線、及び耐力比が前記95%を超えるようなものでは、その捻回特性が2,3回程度に留まるか縦割れを生じ易い。このため、例えばコイルばねとして、平均コイル径(D)に対する線径(d)の比D/dが4倍以下のような過酷形状のばね加工において歩留りに悪影響を及ぼす場合がある。すなわち、捻回値に関わらず、ばね成形は可能であるが、縦割れなく5回以上の捻回値を示す鋼線がばね成形にとって好ましく、6回以上であることがより好ましい。
[Torsion test 1]
Further, as another test method for evaluating the spring workability, it can also be performed with a twist characteristic by the following twist test. The twisting property is the number of times until a test piece taken from the stainless steel wire is held for a distance of 100 times the equivalent wire diameter and broken by twisting and rotating one end side. For example, in the case of a cold-worked stainless steel wire, if the number of twists (twist value) has a high twist characteristic of 5 times or more, for example, about 5 to 10 times or more without vertical cracking It can be widely used for various spring products. And in the steel wire which has been subjected to such aging heat treatment, and in which the yield strength ratio exceeds 95%, the twisting property is limited to a few times or is liable to cause vertical cracks. For this reason, for example, as a coil spring, the yield may be adversely affected in severe spring processing in which the ratio D / d of the wire diameter (d) to the average coil diameter (D) is 4 times or less. That is, although spring forming is possible regardless of the twist value, a steel wire showing a twist value of 5 times or more without vertical cracking is preferable for spring forming, and more preferably 6 times or more.
[捻り試験2]
この捻り試験は、例えばJIS−G4314にも説明されており、またこの捻り試験での破断面を観察することで、該ステンレス鋼線の靭性状況を見ることもできる。
図1はその一例を示すもので、図1Aはほぼ均一な破断面で良好であるのに対し、図1Bでは横断面の一部に捻り割れが認められ、脆性破断したことを示している。前者のような良好な破断面のものでは前記捻り回数を満足することができる。
[Torsion test 2]
This torsion test is described in, for example, JIS-G4314, and the toughness of the stainless steel wire can be observed by observing the fracture surface in this torsion test.
FIG. 1 shows an example thereof. FIG. 1A shows a substantially uniform fracture surface, whereas FIG. 1B shows a torsion crack in a part of the transverse cross section, indicating that a brittle fracture occurred. In the case of a good fracture surface like the former, the number of twists can be satisfied.
次に、本発明が対象とするステンレス鋼線の各構成元素の限定理由について説明する。
なお、本発明では特に注記が無い場合は、元素含有量は質量%を意味する。
Next, the reasons for limiting the constituent elements of the stainless steel wire targeted by the present invention will be described.
In the present invention, unless otherwise noted, the element content means mass%.
Cは伸線加工後に高強度を得るために0.02%以上(以下は全て質量%)添加する。しかし、0.12%を超えて添加すると、鋭敏化して、耐食性が劣化するばかりか、製造性が劣化することから上限を0.12%とする。好ましくは、0.10%未満であり、更に好ましい範囲は、0.04〜0.09%である。 C is added in an amount of 0.02% or more (the following is all by mass%) in order to obtain high strength after wire drawing. However, if added over 0.12%, not only does it become sensitized and the corrosion resistance deteriorates, but also the manufacturability deteriorates, so the upper limit is made 0.12%. Preferably, it is less than 0.10%, and a more preferable range is 0.04 to 0.09%.
Nは、強度に寄与する元素であると共に、炭窒化物を形成し、固溶化熱処理時の冷間加工前の素材の結晶粒を微細化させる効果があるため0.005%以上添加する。しかしながら0.03%を超えて添加するとAlN等の粗大窒化物の形成および延靭性の劣化が起こり、製造性が著しく劣化する。そのため、上限を0.03%とする。N含有量の好ましい下限は0.01%であり、好ましい上限は0.025%である。 N is an element that contributes to strength, and forms carbonitride and has the effect of refining crystal grains of the material before cold working during solution heat treatment, so 0.005% or more is added. However, if added over 0.03%, formation of coarse nitrides such as AlN and deterioration of ductility occur, and the manufacturability deteriorates remarkably. Therefore, the upper limit is made 0.03%. The minimum with preferable N content is 0.01%, and a preferable upper limit is 0.025%.
CおよびNは共に侵入型元素であり、ひずみを生成し、強化に作用する固溶強化やコットレル雰囲気や微細炭窒化物を形成し、金属組織中の転位を固着する効果がある。これらの効果を得るためにC+Nを0.05%以上添加する。しかしC+Nが0.13%を超えて添加すると延靭性が劣化するため上限を0.13%とする。好ましい範囲は、0.08〜0.11%である。 C and N are both interstitial elements, and have the effect of generating strain, forming solid solution strengthening that acts on strengthening, forming a Cottrell atmosphere and fine carbonitride, and fixing dislocations in the metal structure. In order to obtain these effects, 0.05% or more of C + N is added. However, if C + N exceeds 0.13%, ductility deteriorates, so the upper limit is made 0.13%. A preferable range is 0.08 to 0.11%.
Siは脱酸を行うため、0.1%以上添加する。しかし、2.0%を超えて添加するとその効果は飽和するだけでなく、製造性が劣化することから上限を2.0%とする。好ましい範囲は0.3〜1.0%である。 Si is deoxidized, so 0.1% or more is added. However, the addition exceeding 2.0% not only saturates the effect but also deteriorates manufacturability, so the upper limit is made 2.0%. A preferable range is 0.3 to 1.0%.
Mnは、脱酸のため、0.1%以上添加する。しかし、2.0%を超えて添加すると、耐食性劣化、加工誘起α’量が低くなり、強度が低下するだけでなく、耐熱へたり性も劣化することから上限を2.0%にする。好ましい範囲は0.5〜1.5%である。 Mn is added in an amount of 0.1% or more for deoxidation. However, if added over 2.0%, the corrosion resistance is deteriorated and the processing-induced α 'amount is reduced, not only the strength is lowered, but also the heat sag is deteriorated, so the upper limit is made 2.0%. A preferable range is 0.5 to 1.5%.
Niは、素材の延靭性を確保し、伸線加工にて適量の加工誘起マルテンサイト量を得るため、6.8%以上添加する。しかし、9.0%を超えて添加すると、MdS値が低下して加工誘起マルテンサイト量が低くなり強度が低下するばかりか、耐熱へたり性も劣化する。そのため、上限を9.0%にする。好ましい範囲は7.0%超、8.5%以下、より好ましくは7.5〜8.2%である。 Ni is added in an amount of 6.8% or more in order to ensure the ductility of the material and obtain an appropriate amount of work-induced martensite by wire drawing. However, if added over 9.0%, the MdS value decreases, the amount of work-induced martensite decreases, the strength decreases, and the heat sag resistance also deteriorates. Therefore, the upper limit is made 9.0%. A preferable range is more than 7.0% and 8.5% or less, more preferably 7.5 to 8.2%.
Crは、耐食性を確保し、適度な加工誘起マルテンサイト量を得るため、12.0%以上添加する。しかし、14.4%を超えて添加するとMdS値が低下して加工誘起マルテンサイト量が低くなり、強度が低下するばかりか、耐熱へたり性も劣化する。そのため、上限を14.4%にする。好ましい範囲は、13.0〜14.0%である。 Cr is added in an amount of 12.0% or more to ensure corrosion resistance and to obtain an appropriate amount of work-induced martensite. However, if it is added in excess of 14.4%, the MdS value is lowered and the amount of work-induced martensite is lowered, not only the strength is lowered, but also the heat sagability is degraded. Therefore, the upper limit is made 14.4%. A preferable range is 13.0 to 14.0%.
Moは、オーステナイト母相に固溶し母相の硬さを高め、さらに使用時の昇温による熱へたりを緩和する。さらにばねを製造する際の300〜600℃での時効熱処理によりMo系の微細な金属クラスターを加工誘起マルテンサイト中に微細析出させて、高強度化して耐熱へたり性を向上させるのに有効な元素であり、1.0%以上添加する。しかしながら、3.0%を超えて添加すると、その効果は飽和し、MdS値も低下するため加工誘起マルテンサイト量が低くなり強度が低下するばかりか、耐熱へたり性も劣化する。そのため、上限を3.0%にする。好ましい範囲は1.5〜2.6%、より好ましくは1.7%〜2.3%である。 Mo dissolves in the austenite matrix and increases the hardness of the matrix, and further reduces heat sag due to temperature rise during use. Furthermore, it is effective for finely depositing Mo-based fine metal clusters in work-induced martensite by aging heat treatment at 300 to 600 ° C. when manufacturing springs, thereby increasing strength and improving heat resistance. It is an element, and 1.0% or more is added. However, if added over 3.0%, the effect is saturated and the MdS value is lowered, so that the amount of work-induced martensite is lowered and the strength is lowered, and the heat sagability is also degraded. Therefore, the upper limit is made 3.0%. A preferable range is 1.5 to 2.6%, more preferably 1.7% to 2.3%.
Alは、ばねを製造する際の例えば300〜600℃での時効熱処理により微細なNiAl系金属間化合物を加工誘起マルテンサイト中に微細析出させて高強度化して耐熱へたり性を向上させるのに有効な元素であり、0.5%以上添加する。しかしながら、2.0%を超えて添加してもその効果は飽和し、製造性が劣化する。そのため、上限を2.0%とする。好ましい範囲は、0.7〜1.5%、より好ましくは0.9%〜1.2%である。 Al is used to improve heat resistance and sag resistance by finely precipitating fine NiAl-based intermetallic compounds in work-induced martensite by aging heat treatment, for example, at 300 to 600 ° C. when manufacturing springs. It is an effective element and 0.5% or more is added. However, even if added over 2.0%, the effect is saturated and manufacturability deteriorates. Therefore, the upper limit is made 2.0%. A preferable range is 0.7 to 1.5%, more preferably 0.9% to 1.2%.
前記ステンレス鋼線はこれら構成元素により構成されるとともに、前記MdS値が15〜60になるように成分調節がなされ、残部Fe及び若干(例えば通常のステンレス鋼の製造で混入するO:0.001〜0.01%,Zr:0.0001〜0.01%,Sn:0.001〜0.1%,Pb:0.00005〜0.01%,Bi:0.00005〜0.01%,Zn:0.0005〜0.01%等、原料や耐火物に含有される物質など、合計で2.0%以下)の不可避不純物の含有を許容する。 The stainless steel wire is composed of these constituent elements, and the components are adjusted so that the MdS value is 15 to 60, and the balance Fe and some (for example, O: 0.001 mixed in the production of normal stainless steel) -0.01%, Zr: 0.0001-0.01%, Sn: 0.001-0.1%, Pb: 0.00005-0.01%, Bi: 0.00005-0.01%, Zn: 0.0005 to 0.01%, etc., including materials contained in raw materials and refractories, etc. in total of 2.0% or less) is allowed to be contained.
また、本発明は前記構成元素に加えて更に次のいずれか第三元素を含有することができる。 In addition to the above constituent elements, the present invention may further contain any of the following third elements.
その第一のグループにはV,Nb,Ti,W,Taがあり、これら元素は各々微細な炭窒化物を形成して結晶粒を微細化して高強度化するとともに、耐熱へたり性を向上させることに寄与する。その効果は、V:0.01〜1.0%(好ましくは0.05〜0.6%),Nb:0.01〜1.0%(好ましくは0.05〜0.4%),Ti:0.01〜1.0%(好ましくは0.02〜0.2%),W:0.05〜2.0%(好ましくは0.05〜0.5%),Ta:0.05〜2.0%(好ましくは0.1〜0.5%)のうち、いずれか1種類以上の添加で可能となるが、各上限を超えて添加すると炭窒化物が粗大化して製造性を低下させる。したがって、より好ましくは前記併記した好ましい範囲での実施が推奨される。 The first group includes V, Nb, Ti, W, and Ta. These elements each form fine carbonitrides to refine crystal grains and increase strength, and also improve heat resistance. Contributes to The effect is as follows: V: 0.01 to 1.0% (preferably 0.05 to 0.6%), Nb: 0.01 to 1.0% (preferably 0.05 to 0.4%), Ti: 0.01 to 1.0% (preferably 0.02 to 0.2%), W: 0.05 to 2.0% (preferably 0.05 to 0.5%), Ta: 0.0. It becomes possible by addition of any one or more of 0.5 to 2.0% (preferably 0.1 to 0.5%), but if added exceeding each upper limit, the carbonitride becomes coarse and manufacturability Reduce. Therefore, it is more preferable to carry out the operation within the preferable range described above.
同様に第二グループには、ステンレス鋼線の耐食性や靭性、加工性など付帯効果を高めるものであって、必要に応じて次のいずれか元素の添加を許容するものである。 Similarly, the second group enhances incidental effects such as corrosion resistance, toughness, and workability of the stainless steel wire, and allows addition of any of the following elements as necessary.
Cuは、耐食性を向上するのに有効な元素で必要に応じて添加する。しかしながら、0.8%を超えて添加すると、加工硬化が小さくなって、軟質化するばかりか、耐熱へたり性も低下するため、上限を0.8%以下とする。好ましい範囲は0.1〜0.6%である。 Cu is an element effective for improving the corrosion resistance, and is added as necessary. However, if added over 0.8%, the work hardening becomes small and softens, and also the heat sag is reduced, so the upper limit is made 0.8% or less. A preferable range is 0.1 to 0.6%.
Coは延靭性を確保して耐熱へたり性を向上させるため、必要に応じて、0.1%以上添加する。しかしながら、2.0%を超えて添加すると、強度が低下して耐熱へたり性が劣化するため、上限を2.0%にする。好ましい範囲は0.5%〜1.5%である。 Co is added in an amount of 0.1% or more as necessary to ensure ductility and improve heat resistance. However, if added over 2.0%, the strength is lowered and the heat resistance is deteriorated, so the upper limit is made 2.0%. A preferred range is 0.5% to 1.5%.
またBは、該ステンレス鋼の熱間製造性および靭性を向上させるため、必要に応じて、0.0005%以上を添加する。しかしながら、0.015%を超えて添加するとボライドが生成するため、逆に延靭性が低下して、製造性が劣化する。そのため、上限を0.015%にする。好ましい範囲は、0.001〜0.01%である。 Further, B is added in an amount of 0.0005% or more as necessary in order to improve the hot manufacturability and toughness of the stainless steel. However, if added over 0.015%, boride is generated, and conversely, the toughness is lowered and the manufacturability is deteriorated. Therefore, the upper limit is made 0.015%. A preferred range is 0.001 to 0.01%.
更に第三グループとして、Ca,Mg,REMが選定される。これら元素は、脱酸のために含有でき、必要に応じて、Ca:0.0005〜0.01%,Mg:0.0005〜0.01%,REM:0.0005〜0.1%の1種類以上を添加する。しかしながら、各上限を超えて添加すると粗大介在物が生成して製造性が低下することとなる。 Further, Ca, Mg, and REM are selected as the third group. These elements can be contained for deoxidation, and if necessary, Ca: 0.0005 to 0.01%, Mg: 0.0005 to 0.01%, REM: 0.0005 to 0.1% Add one or more. However, if it is added in excess of each upper limit, coarse inclusions are produced and productivity is lowered.
また、本発明ではその他元素としてP及びSを特定範囲にすることで、熱間加工性や延靭性の観点で調整することも好ましい。その許容範囲として、Pは0.015〜0.045%、Sは0.0001〜0.01%とされるが、必要以上の低減は却ってコストアップの要因となり、逆に多量に含有するものでは、非金属介在物など品質低下の要因ともなる。これら各グループは、各々単独に添加できる他、いずれか2種以上のグループを選択して添加できる。 Moreover, in this invention, it is also preferable to adjust from a viewpoint of hot workability and ductility by making P and S into a specific range as another element. As the allowable range, P is 0.015 to 0.045% and S is 0.0001 to 0.01%. However, excessive reduction causes cost increase. Then, it becomes a factor of quality deterioration, such as a nonmetallic inclusion. Each of these groups can be added alone, or any two or more groups can be selected and added.
このように構成された本発明のステンレス鋼線は、例えば前記所定成分組成を有する鋳片を鋳造、熱間圧延を行ないロット線材とした後、これを冷間加工又はその工程間に固溶化熱処理を介して繰り返しながら細径化して、目標線径のステンレス鋼線とすることができる。冷間加工には、前記伸線加工や圧延加工を含み、例えば引抜ダイスやローラーダイスを用いた連続伸線や、圧延ローラーによる圧延加工が採用されるが、特に最終の固溶化熱処理後の冷間加工では、その総加工率を60〜90%とするとよい。これにより、本発明で規定するマトリックス中の加工誘起α’量及び引張強さを実現することができ、同じく本発明で規定するステンレス鋼線の捻回値や耐力比を実現することができる。好ましくは最終冷間総加工率を65〜85%程度、更に好ましくは70〜83%の比較的抑制した範囲内で行うのがよい。 The stainless steel wire of the present invention configured as described above is, for example, cast a slab having the predetermined component composition, hot-rolled into a lot wire, and then cold work or solution heat treatment between the processes. It is possible to obtain a stainless steel wire having a target wire diameter by reducing the diameter while repeating the above. The cold working includes the wire drawing and rolling, and for example, continuous wire drawing using a drawing die or a roller die, or rolling using a rolling roller is adopted. In particular, the cold working after the final solution heat treatment is adopted. In the inter-processing, the total processing rate is preferably 60 to 90%. As a result, it is possible to realize the processing-induced α ′ amount and tensile strength in the matrix defined in the present invention, and it is possible to realize the twist value and yield strength ratio of the stainless steel wire similarly defined in the present invention. Preferably, the final cold total working rate is within a relatively suppressed range of about 65 to 85%, more preferably 70 to 83%.
また、これら冷間加工のより好ましい形態として、例えばその最終仕上げダイスや最終ロール入側の鋼線表面温度を70℃以下になるように加工温度を調整し(好ましくは10〜50℃)、最終仕上げダイスまたは最終圧延での加工率を20%以下、好ましくは10%以下にして、表層均一強加工を施すことが好ましい。これにより、耐熱へたり性を更に向上させることが出来る。 Further, as a more preferable form of these cold working, for example, the processing temperature is adjusted so that the surface temperature of the steel wire on the final finishing die and the final roll entrance is 70 ° C. or less (preferably 10 to 50 ° C.), and the final It is preferable that the processing rate in the finishing die or final rolling is 20% or less, preferably 10% or less, and surface layer uniform strong processing is performed. Thereby, heat-resistant settling property can further be improved.
最終仕上げダイスの入り側鋼線表面温度と、最終仕上げダイスまたは最終圧延での加工率を制御することで耐熱へたり性が更に向上するメカニズムは、現時点では不明である。但し、本発明者らがこれら条件を制御した場合と、制御しなかった場合の鋼線をそれぞれ時効熱処理し、その時効熱処理後鋼線の表層近傍を観察・比較したところ、上記条件を制御した場合の方が、微細化合物が均一分布していることが分かった。このことから、微細化合物が鋼線表層近傍に、より均一に析出することが、耐熱へたり性の更なる向上に影響していると推測できる。 The mechanism by which the heat-resistant sagability is further improved by controlling the surface temperature of the steel wire on the entry side of the final finishing die and the processing rate in the final finishing die or final rolling is not known at this time. However, when the inventors controlled these conditions and when not controlled, the steel wires were each subjected to aging heat treatment, and after aging heat treatment, the vicinity of the surface layer of the steel wire was observed and compared, and the above conditions were controlled. In the case, it was found that the fine compound was uniformly distributed. From this, it can be inferred that the more even precipitation of the fine compound in the vicinity of the steel wire surface layer affects the further improvement of the heat sagability.
また、必要ならば線の表面にNiメッキ等を付与して潤滑性を高めることで、歩留り向上することも有効である。
なお、前記加工率とは、その加工に伴う該ステンレス鋼線の横断面面積の変化率で示され、次式で算出される。
加工率(%)={(加工前の断面積−加工後の断面積)/加工前の断面積}×100
Further, if necessary, it is also effective to improve the yield by imparting Ni plating or the like to the surface of the wire to enhance the lubricity.
In addition, the said process rate is shown by the change rate of the cross-sectional area of this stainless steel wire accompanying the process, and is calculated by following Formula.
Processing rate (%) = {(cross-sectional area before processing−cross-sectional area after processing) / cross-sectional area before processing} × 100
[ばね製品製造方法]
次に、本発明のばね製品に関する発明を説明すれば、該ばね製品は前記何れか構成のステンレス鋼線によって、例えばコイルばねやトーションばね、直線ばねなど種々形状に成形されてなるものであって、更に後記する時効熱処理を施すことでそのばね特性を向上させることができる。そのばね特性は、本発明では前記温間領域で用いられることを前提とすることから、特に環境温度200℃を基準として設定し、その温度における残留剪断ひずみが0.008%以下のものとしている。
[Spring product manufacturing method]
Next, the invention relating to the spring product of the present invention will be described. The spring product is formed by the stainless steel wire having any one of the above-described structures into various shapes such as a coil spring, a torsion spring, and a linear spring. Furthermore, the spring characteristics can be improved by performing an aging heat treatment described later. Since the spring characteristics are premised on the use in the warm region in the present invention, the ambient temperature is set based on 200 ° C. in particular, and the residual shear strain at that temperature is 0.008% or less. .
ばね特性の耐熱へたり性については、例えば図2に示すように、任意応力(例えば400MPa)に相当する高さまで変形させて、これを所定の環境試験条件で加熱保持した後取り出して、その試験前後におけるばね高さに相当する負荷荷重の荷重差を試験前の負荷荷重で除した荷重損失で示すことがある。 As shown in FIG. 2, for example, as shown in FIG. 2, the spring characteristic is deformed to a height corresponding to an arbitrary stress (for example, 400 MPa), heated and held under predetermined environmental test conditions, taken out, and tested. It may be indicated by the load loss obtained by dividing the load difference of the load load corresponding to the spring height before and after by the load load before the test.
しかし、この方法ではその値はばね形状によって異なり、必ずしも標準的ではないことから、本発明では、これに代えて前記残留剪断ひずみ率を用いるもので、またその環境温度も前記するように200℃に設定している。 However, in this method, the value varies depending on the spring shape and is not necessarily standard. Therefore, in the present invention, the residual shear strain rate is used instead, and the ambient temperature is 200 ° C. as described above. Is set.
残留剪断ひずみεとは、所定のばねに対してある一定の荷重又はトルクを加えて変形させ、次に荷重又はトルクを除いたときに残るせん断ひずみ率として定義され、その算出は例えば次式(7)で行われる。すなわち、例えば圧縮コイルばねの場合を説明すれば、図2に示すコイルばねに対して前記所定の圧縮荷重を加えて、ばね高さをSからS1に変位させる。この状態を保持したまま200℃に加熱する。次いで室温に冷却して圧縮荷重を開放する。そして圧縮荷重を開放した時のばね高さをS0とし、ばね高さがS1からS0に復帰したときの荷重を用いて、荷重損失(ΔP)を算出する。具体的には、図2に示す圧縮荷重の負荷されているときのばね高さS1を所定の設定高さとするとき、所定の圧縮荷重で加熱し冷却した後の高さS0のばねと、所定の圧縮荷重で加熱する前の高さSのばねとについて、各々S1の高さまで変位させるのに必要な荷重を所定のばね荷重試験機で測定し、それらの必要な荷重の差を算出し、これを荷重損失(△P)とする。そして、その荷重損失を用いた次式(7)から残留剪断ひずみεが算出される。この残留剪断ひずみεから耐熱へたり性を評価することができる。 The residual shear strain ε is defined as the shear strain rate that remains when a given spring is deformed by applying a certain load or torque, and then the load or torque is removed. 7). That is, for example, in the case of a compression coil spring, the predetermined compression load is applied to the coil spring shown in FIG. 2, and the spring height is displaced from S to S1. While maintaining this state, it is heated to 200 ° C. Then it is cooled to room temperature and the compression load is released. The spring height when the compression load is released is S0, and the load loss (ΔP) is calculated using the load when the spring height returns from S1 to S0. Specifically, when the spring height S1 when the compression load shown in FIG. 2 is applied is set to a predetermined set height, the spring having the height S0 after being heated and cooled with the predetermined compression load, Measure the load necessary to displace each spring up to the height of S1 with a spring of a height S before heating with a compression load of, and calculate the difference between the necessary loads. This is the load loss (ΔP). Then, the residual shear strain ε is calculated from the following equation (7) using the load loss. From this residual shear strain ε, heat sagability can be evaluated.
残留剪断ひずみε={8△PD/πd3G}×100 ・・・・(7)
但し、△P:荷重損失(N)
D:ばねの中心径(mm)・・・・図2のように、対向する鋼線の中心点同士の離間寸法。
d:鋼線の等価線径(mm)
G:鋼線の横弾性係数(N/mm2)(MPa)
Residual shear strain ε = {8ΔPD / πd 3 G} × 100 (7)
△ P: Load loss (N)
D: Center diameter of the spring (mm) ··· As shown in Fig. 2, the distance between the center points of the opposing steel wires.
d: Equivalent wire diameter of steel wire (mm)
G: transverse elastic modulus of steel wire (N / mm 2 ) (MPa)
該残留剪断ひずみが0.008%以下の優れたばね製品では、その使用時の機能低下を軽減するために従来から行われる、例えばヒートセッチング処理が省略できる利点があり、より好ましい残留剪断ひずみは0.005%以下に設定される。 In an excellent spring product having a residual shear strain of 0.008% or less, there is an advantage that, for example, a heat setting process, which is conventionally performed in order to reduce functional deterioration during use, can be omitted, and a more preferable residual shear strain is 0. .005% or less is set.
このようなばね特性をより高めるには、例えば該ばね製品を予め所定温度で加熱処理して、ステンレス鋼線の組織内に、特に表層近傍に微細化合物粒子を均一に析出させる時効熱処理を行うことが推奨される。その時効熱処理は、例えば300〜600℃の温度範囲で、好ましくは3分〜10時間程度の加熱時間が設定される。それによって、例えば図3に示すような微細かつ硬質な化合物を形成分布させることができ、結果として本発明で規定する高強度ばねの残留剪断ひずみを実現することができる。形成される化合物析出は、特に前記ステンレス鋼線が強加工されて析出硬化型になるように予め成分調整されておくことが望まれる。 In order to enhance such spring characteristics, for example, the spring product is heat-treated at a predetermined temperature in advance, and an aging heat treatment is performed to precipitate fine compound particles uniformly in the structure of the stainless steel wire, particularly in the vicinity of the surface layer. Is recommended. In the aging heat treatment, for example, a heating time of about 3 minutes to 10 hours is set in a temperature range of 300 to 600 ° C. Thereby, for example, a fine and hard compound as shown in FIG. 3 can be formed and distributed, and as a result, the residual shear strain of the high-strength spring defined in the present invention can be realized. It is desired that the compound precipitation to be formed is adjusted in advance so that the stainless steel wire is particularly strongly processed into a precipitation hardening type.
時効熱処理のより好ましい条件としては、例えば次式(3)の時効熱処理因子に示すようにそのばね製品の容積や形態によって、設定温度や加熱時間が関係することからその値が100〜10000、好ましくは150〜3000になるように調整しておくことが望ましい。
時効熱処理因子={温度(℃)×処理時間(min)}/2√{ばねの等価線径(mm)×展開長さ(mm)}・・・(3)
展開長さとは、そのばね製品を構成するステンレス鋼線の全長であって、こうした時効熱処理によってそのマトリックス内に所望の前記化合物の析出を図り、材料特性が向上するものとなる。
As a more preferable condition for the aging heat treatment, for example, as shown in the aging heat treatment factor of the following formula (3), the set temperature and the heating time are related depending on the volume and form of the spring product. Is preferably adjusted to 150 to 3000.
Aging heat treatment factor = {temperature (° C.) × treatment time (min)} / 2√ {equivalent wire diameter of spring (mm) × deployed length (mm)} (3)
The developed length is the total length of the stainless steel wire constituting the spring product, and by such aging heat treatment, the desired compound is precipitated in the matrix, and the material characteristics are improved.
その場合、時効熱処理の加熱温度が300℃未満では長時間加熱しても十分な化合物形成が得られず、また600℃を超えると線材が軟化し強度が低下しやすくなるため、より好ましくは400〜580℃程度での処理が推奨される。また、該化合物の形成は加熱時間によってもその析出状態は異なり、粒径や密度が変化することから、少なくとも3分以上の加熱を行うことが好ましい。その状況を含め、前記算式(3)によって適正範囲が設定される。より好ましい適正範囲は、400〜550℃である。 In that case, if the heating temperature of the aging heat treatment is less than 300 ° C., sufficient compound formation cannot be obtained even when heated for a long time, and if it exceeds 600 ° C., the wire is softened and the strength tends to decrease, so that 400 is more preferable. Treatment at about ~ 580 ° C is recommended. In addition, since the precipitation state of the compound varies depending on the heating time, and the particle size and density change, it is preferable to perform heating for at least 3 minutes. Including the situation, the appropriate range is set by the equation (3). A more preferable appropriate range is 400 to 550 ° C.
なお、該化合物は非常に微細であることから、上記時効熱処理条件範囲の殆どにおいて、その存在を詳細に規定するのは困難であり、3次元アトムプローブ又は透過型電子顕微鏡にて確認することができる。特に、時効熱処理温度が高く、長時間になるにつれて化合物は徐々に成長するため、上限付近の処理条件においては化合物の存在を透過型電子顕微鏡にて確認することが可能となる。 In addition, since the compound is very fine, it is difficult to define its existence in detail in most of the above aging heat treatment condition range, and it can be confirmed with a three-dimensional atom probe or a transmission electron microscope. it can. In particular, since the aging heat treatment temperature is high and the compound grows gradually as it becomes longer, the presence of the compound can be confirmed with a transmission electron microscope under the treatment conditions near the upper limit.
例えば、前記図3は、600℃×30min.の時効熱処理によって得たステンレス鋼線の横断面を高倍率に拡大したもので、マルテンサイトのマトリックス中に平均粒径50nm以下のNiAlによる微細化合物が高い密度で析出しており、また、その電子線回折像では、該化合物はB2構造を備えるものであることも確認されている。なお、その平均粒径は、例えば該回折像の任意観察視野内に確認される各化合物粒子の径の平均値で示され、より最適な粒径は20nm以下である。 For example, FIG. 3 shows 600 ° C. × 30 min. The cross section of the stainless steel wire obtained by the aging heat treatment was enlarged at a high magnification, and a fine compound of NiAl having an average particle size of 50 nm or less was precipitated in the martensite matrix at a high density, and the electrons In the line diffraction image, it is also confirmed that the compound has a B2 structure. In addition, the average particle diameter is shown, for example by the average value of the diameter of each compound particle confirmed in the arbitrary observation visual field of this diffraction image, and a more optimal particle diameter is 20 nm or less.
図3のa)は、材料の薄膜の透過型電子顕微鏡の明視野像であり、加工誘起マルテンサイト組織の像が示されている。b)は、その領域の回折像(材料の構造をフーリエ変換したもの)を示しており、加工誘起マルテンサイトのBCC構造に加え、d)に示すようなB2構造のNiAlの存在も確認できる。c)は、B2構造のNiAlの析出物のみが映し出された暗視野像を示す。なお、前記化合物粒子は、上述した最終仕上げダイス入り側鋼線表面温度と、最終仕上げダイスまたは最終圧延での加工率を制御することにより、より均一に分布する傾向が見られる。 FIG. 3 a) is a bright-field image of a transmission electron microscope of a thin film of material, showing an image of a work-induced martensite structure. b) shows a diffraction image of the region (a material obtained by Fourier transform of the material). In addition to the BCC structure of processing-induced martensite, the presence of NiAl having a B2 structure as shown in d) can be confirmed. c) shows a dark field image in which only a precipitate of NiAl having a B2 structure is projected. The compound particles tend to be distributed more uniformly by controlling the surface temperature of the steel wire with the final finishing die and the processing rate in the final finishing die or the final rolling.
このように、前記化合物はその加熱温度や加熱条件、鋼線の加工条件や構成元素によって大きく依存し、例えば高温加熱や長時間加熱では反応が促進し、より大型化や密度アップさせることができる。したがって、所望の化合物形成状態が得られるよう、予備試験を行いながら処理することが望ましい。 As described above, the compound greatly depends on the heating temperature and heating conditions, the processing conditions and constituent elements of the steel wire, and for example, the reaction is accelerated by high-temperature heating or long-time heating, and can be increased in size and density. . Therefore, it is desirable to carry out the treatment while conducting a preliminary test so as to obtain a desired compound formation state.
本発明により得られるばね製品は、高強度で耐熱へたり性に優れることから、従来使用されてきた他のステンレス鋼線やピアノ線などで実施されているばね使用前の予熱調整(ヒートセッチング)工程の省略によるコストダウンが期待でき、前記するようにピアノ線によるものでは特性低下が生じるやや加熱状態の温間域での耐熱ばね用に好適する。また400℃以上の一般高温環境用の耐熱用途への応用も見込まれるなど、その活用範囲は拡大する。 Since the spring product obtained by the present invention has high strength and excellent heat resistance, preheating adjustment (heat setting) before using the spring, which has been carried out with other conventionally used stainless steel wires or piano wires, etc. Cost reduction due to omission of the process can be expected, and the use of piano wire as described above is suitable for heat-resistant springs in the warm region where the characteristics are slightly degraded. In addition, its application range is expanded, for example, application to heat-resistant applications for general high-temperature environments of 400 ° C or higher is expected.
以下、本発明の実施例により、更に説明する。 Hereinafter, the present invention will be further described by examples.
《ステンレス鋼線の製造》
表1に実施例として用いたステンレス鋼の化学成分を示し、あわせて比較材についても併記している。表1、表2とも、本発明範囲から外れる数値にアンダーラインを付している。
<Manufacture of stainless steel wire>
Table 1 shows the chemical components of the stainless steel used as an example, and also shows the comparative materials. In both Tables 1 and 2, numerical values outside the scope of the present invention are underlined.
これらの化学成分の鋼は真空溶解炉にて溶解し、φ178mmの鋳片に鋳造して、その鋳片を熱間鍛造にてφ62mmの棒鋼にした後、更に熱間押出しシミュレーター(1250℃加熱,押出し)でφ10.7mmの線材とした。その後、溶体化処理、酸洗を行い、φ5.5mmまで伸線し、線材とした。 Steels of these chemical components are melted in a vacuum melting furnace, cast into a slab of φ178 mm, the slab is made into a steel bar of φ62 mm by hot forging, and then a hot extrusion simulator (heated at 1250 ° C., A wire rod having a diameter of 10.7 mm was obtained by extrusion. Thereafter, solution treatment and pickling were performed, and the wire was drawn to φ5.5 mm to obtain a wire.
そして、これを原材料として冷間伸線加工及び固溶化熱処理を繰り返し行ないながら素線径2.2mmの軟質線に加工した後、最終の冷間伸線加工で線径φ1.0mmの硬質細線にしたもので、最終の総伸線加工率は80%として実施した。また、加工後の鋼線は表面に厚さ1.2μmのNiめっき層が形成され、その最終仕上げの伸線ダイスの減面率(加工率)を8〜25%,ダイス入り側鋼線表面温度を0〜80℃に調節し、行なったものである。 Then, using this as a raw material, it is processed into a soft wire having a wire diameter of 2.2 mm while repeatedly performing cold wire drawing and solution heat treatment, and then into a hard wire having a wire diameter of φ1.0 mm in the final cold wire drawing. Therefore, the final total wire drawing rate was 80%. The processed steel wire has a 1.2 μm thick Ni plating layer formed on the surface, and the surface reduction rate (processing rate) of the final drawing wire dies is 8-25%. This was performed by adjusting the temperature to 0 to 80 ° C.
本発明に係る実施例材はいずれも問題なく細径加工を行うことができ、引張強さ1800〜2200MPa(N/mm2),耐力比80〜95%,捻回値5回以上の高強度細線が得られ、また加工誘起マルテンサイト量も80〜95vol%を有するものであった。 Each of the example materials according to the present invention can be processed with a small diameter without any problem, and has a tensile strength of 1800 to 2200 MPa (N / mm 2 ), a proof stress ratio of 80 to 95%, and a high strength of 5 or more twists. A thin wire was obtained, and the amount of processing-induced martensite was 80 to 95 vol%.
該引張強さ,0.2%耐力はJIS−Z2241により、またマルテンサイト量は前記[マルテンサイト量の計測]に記載の磁気法によって測定し、捻回値は前記[捻り試験1]、[捻り試験2]記載の方法で測定したもので、その結果を前記表3及び表4に示している。 The tensile strength and 0.2% proof stress are measured according to JIS-Z2241, the martensite amount is measured by the magnetic method described in [Measurement of Martensite Amount], and the twist value is the [Torsion Test 1], [ The results are shown in Tables 3 and 4 above.
《時効特性の検証》
次に前記各ステンレス鋼線の時効熱処理による特性の変化を見る為に、表1または表2の成分を有する実施例1の最終の伸線加工後の各試料を150mm長さに各々切断したものについて、500℃で30分の時効熱処理を行った。その前記(3)式による時効熱処理因子は612である。
<Verification of aging characteristics>
Next, in order to see the change in characteristics of each stainless steel wire due to aging heat treatment, each sample after the final wire drawing of Example 1 having the components shown in Table 1 or Table 2 was cut to a length of 150 mm. Was subjected to an aging heat treatment at 500 ° C. for 30 minutes. The aging heat treatment factor according to the equation (3) is 612.
そして、時効熱処理後の鋼線の引張強さ、耐力、耐力比、捻回値、剛性率を評価した。その結果を前記表3および表4に示す。剛性率はねじり振り子法により評価した。 And the tensile strength of the steel wire after an aging heat treatment, yield strength, yield strength ratio, twist value, and rigidity were evaluated. The results are shown in Tables 3 and 4 above. The rigidity was evaluated by the torsion pendulum method.
本発明に係る実施例材の時効熱処理した鋼線は、引張強さ2100〜2600MPa、耐力比80〜95%、剛性率77000MPa以上の優れた高強度特性を有するものであった。なお、その任意横断面の顕微鏡観察結果として、図3と同様に平均粒径が3〜10nm程度のNiAl粒子からなる析出化合物が確認できた。 The steel wires subjected to the aging heat treatment of the example materials according to the present invention had excellent high strength characteristics with a tensile strength of 2100 to 2600 MPa, a proof stress ratio of 80 to 95%, and a rigidity of 77000 MPa or more. As a result of microscopic observation of the arbitrary cross section, a precipitated compound composed of NiAl particles having an average particle diameter of about 3 to 10 nm was confirmed as in FIG.
なお、捻回値については、時効熱処理を施した場合は、何れの鋼線においても5回捻った時点で縦割れを発生した。 In addition, about the twist value, when performing the aging heat processing, the vertical crack generate | occur | produced at the time of twisting 5 times in any steel wire.
《ばね製品の検証》
次に、実施例2の効果を更に検証するため、時効熱処理前の各ステンレス鋼線を用いて各々平均コイル径:7mm,有効捲数:4.5捲,ばね自由長:25mm,展開長さ:100mmの圧縮コイルばねにコイリング加工するとともに、同様に500℃、30分の時効熱処理を施して実際のばね製品における耐熱へたり性を評価した。耐熱へたり性は前記[ばね製品製造方法]記載の方法により200℃で、600MPaの圧縮応力を負荷し96時間保持する条件で行ったものである。
<Verification of spring products>
Next, in order to further verify the effect of Example 2, using each stainless steel wire before aging heat treatment, average coil diameter: 7 mm, effective number of coils: 4.5 mm, spring free length: 25 mm, unfolded length : 100 mm compression coil spring was coiled and similarly subjected to aging heat treatment at 500 ° C. for 30 minutes to evaluate the heat resistance of the actual spring product. The heat sagability was measured under the conditions described in [Method for producing spring product] at 200 ° C. under the condition of applying a compressive stress of 600 MPa and holding for 96 hours.
その結果は、前記表3および表4に一覧しており、いずれの実施例材も残留剪断ひずみが0.008%以下で、高強度で耐熱へたり性に優れることが確認された。一方、比較例材では、No.51以外は、いずれも同剪断ひずみ特性は大きく低下するものであり、本発明の効果が認められる。No.51は、残留剪断ひずみは小さいものであったが、強度が不十分であった。 The results are listed in Tables 3 and 4 above, and it was confirmed that all of the examples have a residual shear strain of 0.008% or less, high strength and excellent heat resistance. On the other hand, in the comparative material, No. Except for 51, the same shear strain characteristics are greatly reduced, and the effect of the present invention is recognized. No. No. 51 had a small residual shear strain, but had insufficient strength.
製造性については、線材圧延、伸線加工、ばね加工にて割れ、断線、折損が生じた場合は、製造不可として評価した。本発明品では問題なくばね製品まで製造が可能であった。 About manufacturability, when cracking, disconnection, or breakage occurred during wire rod rolling, wire drawing, or spring processing, it was evaluated as unmanufacturable. The product of the present invention could be manufactured to a spring product without any problem.
《時効条件の影響》
次に前記ステンレス鋼線およびばね材の時効熱処理条件の影響を見るために、表1の本発明鋼のA,D鋼および表2の比較鋼のAP鋼を前記実施例1の《ステンレス鋼線の製造》記載の方法で製造したφ1.0mmの冷間伸線ままの鋼線および前記実施例3の《ばね製品の検証》記載の方法で冷間伸線まま鋼線で製造した時効熱処理前のコイルばねについて、各々温度250〜650℃で2分〜10時間で時効熱処理を実施した。そして、時効熱処理後の鋼線の引張強さ,コイルばねの耐熱へたり性を評価した。その一部結果を表5,図4に示す。
<Effect of aging conditions>
Next, in order to see the influence of the aging heat treatment conditions of the stainless steel wire and spring material, the steels A and D of the present invention steel in Table 1 and the AP steel of the comparative steel in Table 2 are referred to as the “stainless steel wire of Example 1”. Before the aging heat treatment manufactured with the steel wire as cold-drawn with a diameter of φ1.0 mm manufactured according to the method described in the above and the steel wire as cold-drawn according to the method described in “Verification of spring products” in Example 3 above. Each of the coil springs was subjected to an aging heat treatment at a temperature of 250 to 650 ° C. for 2 minutes to 10 hours. Then, the tensile strength of the steel wire after the aging heat treatment and the heat sagability of the coil spring were evaluated. The partial results are shown in Table 5 and FIG.
引張強さは特に温度450〜550℃あたりでピークが見られ、600℃ではやや軟化しており、同様に残留剪断ひずみについても、いずれもほぼ0.008%以下の特性が得られているが、600℃辺りまで高めた温度範囲では、その特性がやや低下していることが認められた。また、前記時効熱処理因子が150〜825程度のものでは残留ひずみ特性が0.005%以下で、非常に好ましいものであった。 The tensile strength has a peak especially at a temperature of 450 to 550 ° C., and is somewhat softened at 600 ° C. Similarly, the residual shear strain is almost 0.008% or less. In the temperature range increased up to around 600 ° C., it was recognized that the characteristics were slightly deteriorated. Further, when the aging heat treatment factor was about 150 to 825, the residual strain characteristic was 0.005% or less, which was very preferable.
次に、表1に記載のA,D鋼を実施例1に記載の方法で伸線して採取した、線径φ1.8mmの軟質線材を原料材として、表面に金属石鹸の潤滑剤を付与して冷間伸線装置によって線径1.0mmの硬質細線への細径加工に続いて、更に多段圧延装置による冷間圧延加工によって、最終的に厚さ0.2mmに押圧し硬質平線を製造した。この圧延加工では、最終仕上げの圧延ロール入側の鋼線表面温度が45℃になるように最適な冷却方法を採用した。 Next, the A and D steels listed in Table 1 were drawn by the method described in Example 1 and a soft wire with a wire diameter of φ1.8 mm was used as a raw material, and a metal soap lubricant was applied to the surface. Then, following the thinning to a hard fine wire with a wire diameter of 1.0 mm by a cold wire drawing device, the solid flat wire is finally pressed to a thickness of 0.2 mm by cold rolling with a multi-stage rolling device. Manufactured. In this rolling process, an optimum cooling method was adopted so that the surface temperature of the steel wire on the entrance side of the final finishing roll was 45 ° C.
その固溶化熱処理後の総加工率は83%であり、前記多段の冷間圧延加工に伴う材料割れや断線などのトラブルはなく、良好な加工性を持つものであることが確認された。
そして、その平線によるばね製品での特性評価の為に、表面の付着潤滑剤を溶剤除却した後、前記実施例2と同様に500℃で30minの時効熱処理を行ない、その熱処理前後における該平線の特性を評価した。
結果を表6に示す。
The total processing rate after the solution heat treatment was 83%, and it was confirmed that there was no trouble such as material cracking or disconnection associated with the multi-stage cold rolling processing, and that there was good workability.
Then, in order to evaluate the characteristics of the spring product using the flat wire, after removing the lubricant adhering to the surface, an aging heat treatment was performed at 500 ° C. for 30 minutes as in Example 2, and the flattening before and after the heat treatment was performed. The characteristics of the lines were evaluated.
The results are shown in Table 6.
ここで、引張強さは実施例1と同様に引張試験方法により評価した。また残留剪断ひずみ特性は、前記実施例3と同様に温度200℃での特性として、所定長さの該平線の両端に捻り応力を加えて解除したときの戻り角度の変化で評価した。
また、ばねの場合と同様にして、荷重損失や弾性係数、断面積を用いて、平線の残留せん断ひずみを算出した。なお、平線においては、ばねの場合と異なり、荷重損失として、フラットな平線の幅寸法の例えば5〜50倍程度の範囲内で任意に設定される距離を標点距離とし、その両端間で所定応力を加えて捻り、加熱保持、開放した平線と、試験当初の平線とについて、各々同じ捻り角度にするのに要する荷重の差を用いた。
この結果に見られるように、該ステンレス鋼の平線は、例えばウエーブスプリング用のばね用材料として使用可能な優れた機械的特性を有している。またその表面性状も微細結晶粒に伴って平滑性に優れた光輝表面が得られ、好ましいものであった。
Here, the tensile strength was evaluated by the tensile test method in the same manner as in Example 1. Residual shear strain characteristics were evaluated as changes at a return angle when a twist stress was applied to both ends of the flat wire having a predetermined length as a characteristic at a temperature of 200 ° C. as in Example 3.
Further, the residual shear strain of the flat wire was calculated using the load loss, elastic modulus, and cross-sectional area in the same manner as in the case of the spring. In the case of a flat wire, unlike the case of a spring, the load loss is a distance set arbitrarily within a range of, for example, about 5 to 50 times the width of the flat flat wire, and the distance between both ends The difference in the load required to obtain the same twist angle was used for the flat wire twisted, heated and held and released by applying a predetermined stress and the flat wire at the beginning of the test.
As can be seen from this result, the stainless steel flat wire has excellent mechanical properties that can be used as a spring material for, for example, a wave spring. Also, the surface properties were preferable because a bright surface with excellent smoothness was obtained with the fine crystal grains.
以上説明のように、本発明に係わるステンレス鋼線を用いた高強度ばねは、いずれもその伸線加工状態で1800〜2200MPaの引張強さとともに加工誘起マルテンサイト量をより増加することで、その後の時効熱処理に伴うばね特性を大きく向上し、高強度かつ耐熱へたり性にも優れることから、これを例えば圧縮や引張コイルばね、トーションばね、その他種々のばね用製品に応用され、高強度かつ耐熱へたり性に優れたばね製品として用い得る。 As described above, the high-strength spring using the stainless steel wire according to the present invention increases the amount of work-induced martensite with a tensile strength of 1800 to 2200 MPa in the wire drawing state, and thereafter The spring characteristics associated with aging heat treatment are greatly improved, and the strength and heat resistance are also excellent, so this is applied to, for example, compression, tension coil springs, torsion springs, and other various spring products, It can be used as a spring product with excellent heat resistance.
具体的な用途として、例えば自動車のエンジン周りや電装系等の加温状態の温間領域で用いられるばね製品をはじめ、家電製品用途の耐熱ばね用への応用が好適するが、これ以外においても、例えば、耐熱高温領域で用いられる高強度ロープ用、耐熱シャフト用、耐熱ピン用など種々の高強度耐熱特性の線状製品にも利用可能であり、産業上有用である。 Specific applications are suitable for use in heat-resistant springs for household appliances, including spring products used in warm regions such as around the engine of automobiles and electrical systems, etc. For example, it can be used for various high-strength heat-resistant linear products such as for high-strength ropes, heat-resistant shafts, and heat-resistant pins used in heat-resistant and high-temperature regions, and is industrially useful.
Claims (11)
(1)式で表される加工誘起マルテンサイト生成指数MdS値が15〜60であり、且つ、マトリックス中の加工誘起マルテンサイト量が80〜99vol.%で、引張強さ1800〜2200MPaを備えることを特徴とする高強度ステンレス鋼線。
MdS=551−462(C+N)−9.2Si−8.1Mn−29(Ni+Cu)−13.7Cr−18.5Mo…(1)
但し、式中の元素記号は、当該元素の含有量(質量%)を意味する。 % By mass, C: 0.02 to 0.12%, and N: 0.005 to 0.03%, and 0.050% ≦ (C + N) ≦ 0.13%, Si: 0.1 -2.0%, Mn: 0.1-2.0%, Ni: 6.8-9.0%, Cr: 12.0-14.4%, Mo: 1.0-3.0%, And Al: 0.5% to 2.0%, a high-strength stainless steel wire that has excellent heat sag by being subjected to an aging heat treatment composed of the balance Fe and inevitable impurities,
The processing induced martensite generation index MdS value represented by the formula (1) is 15 to 60, and the processing induced martensite amount in the matrix is 80 to 99 vol. %, A high-strength stainless steel wire having a tensile strength of 1800-2200 MPa.
MdS = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (1)
However, the element symbol in a formula means content (mass%) of the said element.
残留剪断ひずみε={8ΔPD/πd3G}×100…(2)
但し、ΔP:荷重損失(N)、D:ばねの中心径(mm)、d:鋼線の等価線径(mm)、G:鋼線の横弾性係数(N/mm2) It is comprised with the stainless steel wire of Claim 6, and the residual shear strain represented by (2) Formula in environmental temperature 200 degreeC is (epsilon) <= 0.008%, and the particle size of 50 nm or less is in the matrix of a steel wire. A high-strength spring having excellent heat-sagging characteristics, comprising NiAl-based fine compound particles.
Residual shear strain ε = {8ΔPD / πd 3 G} × 100 (2)
Where ΔP: load loss (N), D: center diameter of spring (mm), d: equivalent wire diameter of steel wire (mm), G: transverse elastic modulus of steel wire (N / mm 2 )
残留剪断ひずみε={8ΔPD/πd3G}×100…(2)
但し、ΔP:荷重損失(N)、D:ばねの中心径(mm)、d:鋼線の等価線径(mm)、G:鋼線の横弾性係数(N/mm2) The stainless steel wire according to any one of claims 1 to 5 and 7, which is manufactured by performing cold working at a total working rate of 60 to 90% on a predetermined equivalent wire diameter after solution heat treatment. After forming into a spring shape, NiAl-based fine compound particles having a particle size of 50 nm or less are precipitated in the matrix of the steel wire by further performing an aging heat treatment at a temperature of 300 to 600 ° C., and at an environmental temperature of 200 ° C. (2) A method for producing a high-strength spring excellent in heat sag resistance, comprising producing a high-strength spring having a residual shear strain represented by the formula ε ≦ 0.008%.
Residual shear strain ε = {8ΔPD / πd 3 G} × 100 (2)
Where ΔP: load loss (N), D: center diameter of spring (mm), d: equivalent wire diameter of steel wire (mm), G: transverse elastic modulus of steel wire (N / mm 2 )
時効熱処理因子={温度(℃)×処理時間(min)}/2√{ばねの等価線径(mm)×展開長さ(mm)}・・・(3) The method for producing a high-strength spring having excellent heat sag resistance according to claim 10 , wherein the aging heat treatment with an aging heat treatment factor of the following formula (3) is 100 to 10,000.
Aging heat treatment factor = {temperature (° C.) × treatment time (min)} / 2√ {equivalent wire diameter of spring (mm) × deployed length (mm)} (3)
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Families Citing this family (33)
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PL3150736T3 (en) * | 2014-05-29 | 2020-03-31 | Nippon Steel Corporation | Heat-treated steel material and method for producing same |
MX2016015580A (en) | 2014-05-29 | 2017-03-23 | Nippon Steel & Sumitomo Metal Corp | Heat-treated steel material and method for producing same. |
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Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1402682A (en) * | 1963-08-02 | 1965-06-11 | Armco Steel Corp | Chrome-nickel aluminum stainless steels and their application |
BE651249A (en) * | 1963-08-02 | 1964-11-16 | ||
JPS6036649A (en) * | 1983-08-05 | 1985-02-25 | Nisshin Steel Co Ltd | Precipitation hardening martensitic stainless steel with superior toughness |
JPS61114415A (en) * | 1984-11-08 | 1986-06-02 | 日立電線株式会社 | Clad spring material for electric conduction |
JPS6220857A (en) * | 1985-07-19 | 1987-01-29 | Daido Steel Co Ltd | High-strength stainless steel |
JPH0768584B2 (en) * | 1986-06-09 | 1995-07-26 | 日新製鋼株式会社 | Manufacturing method of stainless steel for springs having excellent spring characteristics |
JPH02310339A (en) * | 1989-05-24 | 1990-12-26 | Kawasaki Steel Corp | Martensitic stainless steel having excellent strength, spring characteristics and formability |
JP3482053B2 (en) | 1995-11-24 | 2003-12-22 | 日本金属株式会社 | Stainless steel for heat-resistant spring and method of manufacturing the same |
JPH1068050A (en) | 1996-08-27 | 1998-03-10 | Hitachi Metals Ltd | Stainless steel for spring excellent in thermal settling resistance |
JP3492531B2 (en) * | 1998-10-05 | 2004-02-03 | 住友電工スチールワイヤー株式会社 | Heat resistant stainless steel |
JP4489928B2 (en) * | 2000-11-09 | 2010-06-23 | 新日鐵住金ステンレス株式会社 | High strength austenitic stainless steel wire |
SE526881C2 (en) | 2001-12-11 | 2005-11-15 | Sandvik Intellectual Property | Secretion curable austenitic alloy, use of the alloy and preparation of a product of the alloy |
CN1263880C (en) * | 2002-05-08 | 2006-07-12 | 新日本制铁株式会社 | High strength stainless steel wire excellent in ductility-toughness and modulus of rigidity and method for production thereof |
JP4163055B2 (en) | 2003-06-24 | 2008-10-08 | 日本精線株式会社 | Stainless steel wire for heat-resistant springs and heat-resistant spring products using the same |
JP4519513B2 (en) * | 2004-03-08 | 2010-08-04 | 新日鐵住金ステンレス株式会社 | High-strength stainless steel wire with excellent rigidity and manufacturing method thereof |
JP4319083B2 (en) * | 2004-04-14 | 2009-08-26 | 新日鐵住金ステンレス株式会社 | Metastable austenitic stainless steel wire for high strength steel wire for springs with excellent rigidity |
JP4790539B2 (en) * | 2006-08-18 | 2011-10-12 | 日本精線株式会社 | High-strength, high-elasticity stainless steel and stainless steel wire |
JP5154122B2 (en) * | 2007-03-29 | 2013-02-27 | 日本精線株式会社 | High strength stainless steel and high strength stainless steel wire using the same |
JP5091732B2 (en) * | 2008-03-17 | 2012-12-05 | 日新製鋼株式会社 | Stainless steel for low Ni springs with excellent sag resistance and bendability |
JP5744678B2 (en) * | 2010-10-07 | 2015-07-08 | 新日鐵住金ステンレス株式会社 | Precipitation hardening type metastable austenitic stainless steel wire excellent in fatigue resistance and method for producing the same |
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WO2024018520A1 (en) | 2022-07-19 | 2024-01-25 | 日鉄ステンレス株式会社 | High strength stainless steel wire and spring |
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