KR20210036916A - Spring steel with excellent fatigue life and its manufacturing method - Google Patents
Spring steel with excellent fatigue life and its manufacturing method Download PDFInfo
- Publication number
- KR20210036916A KR20210036916A KR1020217001643A KR20217001643A KR20210036916A KR 20210036916 A KR20210036916 A KR 20210036916A KR 1020217001643 A KR1020217001643 A KR 1020217001643A KR 20217001643 A KR20217001643 A KR 20217001643A KR 20210036916 A KR20210036916 A KR 20210036916A
- Authority
- KR
- South Korea
- Prior art keywords
- fatigue life
- steel
- excellent fatigue
- rolling
- temperature
- Prior art date
Links
- 229910000639 Spring steel Inorganic materials 0.000 title claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 22
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 28
- 239000000956 alloy Substances 0.000 claims abstract description 28
- 239000002244 precipitate Substances 0.000 claims abstract description 13
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 8
- 239000000203 mixture Substances 0.000 claims abstract description 8
- 239000013078 crystal Substances 0.000 claims abstract description 6
- 238000012545 processing Methods 0.000 claims abstract description 6
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 5
- FBPFZTCFMRRESA-JGWLITMVSA-N D-glucitol Chemical group OC[C@H](O)[C@@H](O)[C@H](O)[C@H](O)CO FBPFZTCFMRRESA-JGWLITMVSA-N 0.000 claims abstract description 4
- 229910000975 Carbon steel Inorganic materials 0.000 claims abstract 11
- 239000010962 carbon steel Substances 0.000 claims abstract 11
- 229910000831 Steel Inorganic materials 0.000 claims description 45
- 239000010959 steel Substances 0.000 claims description 45
- 238000005096 rolling process Methods 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 27
- 238000010438 heat treatment Methods 0.000 claims description 22
- 238000005496 tempering Methods 0.000 claims description 20
- 238000010791 quenching Methods 0.000 claims description 18
- 230000000171 quenching effect Effects 0.000 claims description 18
- 230000008569 process Effects 0.000 claims description 16
- 238000007670 refining Methods 0.000 claims description 15
- 238000003723 Smelting Methods 0.000 claims description 13
- 229910052799 carbon Inorganic materials 0.000 claims description 8
- 239000002893 slag Substances 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 6
- 239000003245 coal Substances 0.000 claims description 6
- 238000009987 spinning Methods 0.000 claims description 6
- 239000007789 gas Substances 0.000 claims description 5
- 229910052698 phosphorus Inorganic materials 0.000 claims description 5
- 238000004513 sizing Methods 0.000 claims description 5
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- 238000009849 vacuum degassing Methods 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 4
- 238000005204 segregation Methods 0.000 claims description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052786 argon Inorganic materials 0.000 claims description 3
- 238000007872 degassing Methods 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 2
- 230000004048 modification Effects 0.000 claims 1
- 238000012986 modification Methods 0.000 claims 1
- 238000004886 process control Methods 0.000 claims 1
- 238000005491 wire drawing Methods 0.000 claims 1
- 229910002651 NO3 Inorganic materials 0.000 abstract 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 abstract 1
- 239000000463 material Substances 0.000 description 31
- 239000011572 manganese Substances 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 9
- 230000001965 increasing effect Effects 0.000 description 8
- 238000013461 design Methods 0.000 description 7
- 238000005261 decarburization Methods 0.000 description 5
- 229910052720 vanadium Inorganic materials 0.000 description 5
- 238000005275 alloying Methods 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052748 manganese Inorganic materials 0.000 description 4
- 229910052758 niobium Inorganic materials 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- 229910052710 silicon Inorganic materials 0.000 description 4
- 238000010792 warming Methods 0.000 description 4
- 229910019582 Cr V Inorganic materials 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 3
- 239000002436 steel type Substances 0.000 description 3
- 229910000851 Alloy steel Inorganic materials 0.000 description 2
- 229910000914 Mn alloy Inorganic materials 0.000 description 2
- 229910006639 Si—Mn Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000007667 floating Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 150000001247 metal acetylides Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000003921 oil Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910019819 Cr—Si Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910001182 Mo alloy Inorganic materials 0.000 description 1
- 206010039897 Sedation Diseases 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 229910008458 Si—Cr Inorganic materials 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 230000002929 anti-fatigue Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910001567 cementite Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000036425 denaturation Effects 0.000 description 1
- 238000004925 denaturation Methods 0.000 description 1
- 238000006392 deoxygenation reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000009661 fatigue test Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
- 230000000116 mitigating effect Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000036280 sedation Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- 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
- C21D9/525—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length for wire, for rods
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/1206—Accessories for subsequent treating or working cast stock in situ for plastic shaping of strands
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
- B22D11/20—Controlling or regulating processes or operations for removing cast stock
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
-
- 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
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/58—Oils
-
- 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
- C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
- C21D1/60—Aqueous agents
-
- 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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/04—Modifying the physical properties of iron or steel by deformation by cold working of the surface
- C21D7/06—Modifying the physical properties of iron or steel by deformation by cold working of the surface by shot-peening or the like
-
- 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
-
- 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
- C21D9/02—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for springs
-
- 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
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/573—Continuous furnaces for strip or wire with cooling
- C21D9/5735—Details
- C21D9/5737—Rolls; Drums; Roll arrangements
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/06—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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- C—CHEMISTRY; METALLURGY
- 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
- C21D2211/001—Austenite
-
- 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
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
- C21D9/562—Details
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
피로수명이 우수한 탄소강 및 그의 제조방법으로서, 그 화학 성분의 중량백분율은 C：0.52-0.62%；Si：1.20-1.45%；Mn：0.25-0.75%；Cr：0.30-0.80%；V：0.01-0.15%；Nb：0.001-0.05%；N：0.001-0.009%；O：0.0005-0.0040%；P：≤0.015%；S：≤0.015%；Al：≤0.0045%이고, 나머지는 Fe와 불가피한 불순물이며, 또한 0.02≤(2Nb+V)/(20N+C)≤0.40을 동시에 만족시킨다. 본 발명의 스프링강의 현미경 조직은 템퍼드 투르스타이트(tempered troostite)+소르바이트 조직이고, 원 오스테나이트의 결정입자 크기는 80um 미만이며, 합금 질탄 석출물의 크기는 5-60nm이고, 단일 입자 개재물의 최대 폭은 30um 미만이다. 상기 스프링강 가공 강도는 2020MPa 이상이며, 이와 동시에 양호한 소성 인성(단면수축율≥40%)을 구비하고, 피로수명은 ≥80만회로서, 자동차, 기계 등 업계의 고응력 스프링의 응용 수요를 충족시킬 수 있다.Carbon steel with excellent fatigue life and its manufacturing method. The weight percentage of its chemical composition is C:0.52-0.62%; Si:1.20-1.45%; Mn:0.25-0.75%; Cr:0.30-0.80%; V:0.01--0.62%; 0.15%; Nb: 0.001-0.05%; N: 0.001-0.009%; O: 0.0005-0.0040%; P: ≤ 0.015%; S: ≤ 0.015%; Al: ≤ 0.0045%; the remainder is Fe and inevitable impurities And 0.02≦(2Nb+V)/(20N+C)≦0.40 are satisfied at the same time. The microscopic structure of the spring steel of the present invention is a tempered troostite + sorbite structure, the crystal grain size of the original austenite is less than 80 μm, the size of the alloy nitrate precipitate is 5-60 nm, and the maximum of single grain inclusions The width is less than 30um. The spring steel processing strength is more than 2020 MPa, and at the same time, it has good plastic toughness (cross-sectional shrinkage ≥40%), and the fatigue life is ≥800,000 times, which can meet the application demands of high-stress springs in industries such as automobiles and machinery. have.
Description
본 발명은 스프링강 및 그의 제조방법에 관한 것으로서, 특히 가공강도가 2020MPa 이상이고, 단면수축율이 ≥40%이며, 조직이 미세하고, 강질의 순정도가 높은 동시에, 저비용의 피로 수명이 탁월한 자동차 스프링에 응용될 수 있는 피로수명이 우수한 스프링강 및 그의 제조방법에 관한 것이다.The present invention relates to a spring steel and its manufacturing method, in particular, an automotive spring having a processing strength of 2020 MPa or more, a cross-sectional shrinkage ratio of ≥40%, a fine structure, high purity of steel, and excellent fatigue life at a low cost. It relates to a spring steel having excellent fatigue life that can be applied to and a method of manufacturing the same.
스프링은 중요한 충격 완화 및 기능부재로써 사회의 생산 및 생활 방면에 모두 널리 사용되고 있으며, 교통운수, 기계제조, 자동차 공업, 군수 및 일상생활에 널리 응용되고 있다. 스프링은 탄성 범위 내에서 사용되며, 언로드 후에는 원래의 위치로 회복되어야 하므로, 소성변형이 작을수록 좋으며, 따라서 강선은 높은 탄성한계(elastic limit), 항복강도와 인장강도를 지녀야 한다. 항복비(yield ratio)가 높을수록, 탄성한계는 인장강도에 가까워지며, 따라서 강도의 이용률을 높일수록 제조되는 스프링의 탄력이 강해진다. 스프링은 탄성변형에 의지하여 충격 에너지를 흡수하므로, 스프링 강선은 반드시 높은 소성이 있어야만 하는 것은 아니며, 최소한 스프링 성형을 견딜 수 있는 소성, 및 충격 에너지를 견딜 수 있는 충분한 인성(toughness)을 지녀야 한다. 스프링은 통상적으로 교번응력(alternating stress)의 작용 하에 장시간 작동하기 때문에, 높은 피로한계, 및 양호한 크리프 저항(creep resisting)과 항이완 성능을 지녀야 한다.Spring is an important shock mitigation and functional member, and is widely used in both the production and life aspects of society, and is widely applied in transportation, machinery manufacturing, automobile industry, military and daily life. Since the spring is used within the elastic range and must be restored to its original position after unloading, the smaller the plastic deformation is, the better. Therefore, the steel wire must have a high elastic limit, yield strength and tensile strength. The higher the yield ratio, the closer the elastic limit is to the tensile strength, and thus, the higher the utilization rate of the strength, the stronger the elasticity of the manufactured spring. Since the spring absorbs impact energy by relying on elastic deformation, the spring steel wire does not necessarily have a high plasticity, and at least has a plasticity capable of withstanding spring forming and sufficient toughness to withstand the impact energy. Since the spring usually operates for a long time under the action of alternating stress, it must have a high fatigue limit, and good creep resisting and anti-relaxation performance.
자동차 및 기계 업계의 기술이 진보함에 따라, 스프링 부품의 강도 및 피로 수명에 대해 보다 높은 요구가 제기되고 있으며, 고강도, 양호한 소성 및 항피로 신뢰성이 높은 스프링 제조용 재료의 개발은 각국 선진 철강기업들의 주요 관심사이다.With the advancement of technology in the automobile and machinery industry, higher demands are being placed on the strength and fatigue life of spring parts, and the development of materials for spring manufacturing with high strength, good plasticity, and anti-fatigue reliability is a major part of advanced steel companies in each country. It's a concern.
현재 통상적인 Cr-V계, Cr-Mn계, Si-Mn계 스프링 강재는 고강도 스프링 생산 요건을 충족시킬 수 없으며, 강도가 보다 높고, 항복비가 보다 우수한 상용 Si-Cr계 스프링강 역시 이미 강도와 피로수명이 한계에 도달하였다.Currently, the usual Cr-V, Cr-Mn, and Si-Mn spring steels cannot meet the requirements for high strength spring production, and commercial Si-Cr spring steels with higher strength and better yield ratio are also already in terms of strength and strength. The fatigue life has reached its limit.
중국 특허 CN101787493B에 공개된 고강도 스프링강 합금의 성분은 0.56%～0.64%의 C, 0.80%～1.10%의 Si, 0.80%～1.20%의 Mn, P≤0.035%, S≤0.03%, 0.80%～1.20%의 Cr, 0.60%～1.00%의 Mo, 0.20%～0.30%의 V, 0.05%～0.12%의 Nb， 0.01%～0.060%의 N, O．02%～0.07%의 RE이고, 나머지는 Fe이다. 상기 설계 재료는 Mn, Cr, Mo 합금 원소의 첨가가 비교적 많으며, 그 중 Mo는 주로 강의 템퍼링 안정성, 내구적 크리프 저항성, 내열성 등을 향상시키는데 사용된다.The components of the high-strength spring steel alloy disclosed in Chinese patent CN101787493B are 0.56% to 0.64% of C, 0.80% to 1.10% of Si, 0.80% to 1.20% of Mn, P≤0.035%, S≤0.03%, 0.80% to 1.20% Cr, 0.60% to 1.00% Mo, 0.20% to 0.30% V, 0.05% to 0.12% Nb, 0.01% to 0.060% N, O. 02% to 0.07% RE, and the rest It is Fe. The design material contains a relatively large amount of Mn, Cr, and Mo alloy elements, among which Mo is mainly used to improve the tempering stability, durable creep resistance, and heat resistance of the steel.
중국 특허 CN100455691C에 공개된 스프링강 합금의 성분은 0.4-0.6%의 C，1.7-2.5%의 Si，0.1-0.4의 Mn，0.5-2.0%의 Cr，0-0.006%의 N，0.021-0.07%의 Al이다. 고탄소 고규소 저망간 합금 설계 노선을 채택하였으며, 잔여 오스테나이트의 양과 크기 형상의 제어를 통해 강의 내수소취성(hydrogen brittleness)의 강화를 주로 고려하였으나, 재료의 ??칭과 템퍼링 과정에 대한 요구가 높은 동시에, 합금 AL의 함량이 높아 제련 과정에서 불순물의 제어 난도가 증가하며, 경취성(Hard Brittle) 산화알루미늄은 스프링의 피로수명 저하를 초래하기가 매우 쉽다.The components of the spring steel alloy disclosed in Chinese patent CN100455691C are 0.4-0.6% C, 1.7-2.5% Si, 0.1-0.4 Mn, 0.5-2.0% Cr, 0-0.006% N, 0.021-0.07% Is Al. A high-carbon, high-silicon, low-manganese alloy design route was adopted, and the reinforcement of the hydrogen brittleness of steel was mainly considered by controlling the amount and size of residual austenite, but the demand for the tempering and tempering process of the material. At the same time, the high content of alloy AL increases the difficulty in controlling impurities during the smelting process, and hard brittle aluminum oxide is very easy to cause a decrease in the fatigue life of the spring.
중국 특허 CN1279204C에 공개된 스프링강 합금의 성분 설계는 다음과 같다: 0.30-0.50%의 C，0.80-2.0%의 Si，0.50-1.0%의 Mn，0.40-1.0%의 Cr，0.01-0.5%의 W，0.08-0.30%의 V，0.005-0.25%의 희토 원소이며, 0.001-0.10%의 B를 더 함유할 수 있다. 상기 합금은 주로 저탄소 설계를 채택하여, Si 원소 함량을 높여 강도를 향상시킴과 동시에, W 원소로 강의 ??칭 경화능(quenching hardenability)을 높이고, 변형저항(deformation resistance)을 향상시키고 탈탄(carbon elimination)을 방지하였으나, 단 W 및 희토 원소는 제련, 열처리 제어의 난도가 비교적 높다.The composition design of the spring steel alloy disclosed in Chinese patent CN1279204C is as follows: 0.30-0.50% C, 0.80-2.0% Si, 0.50-1.0% Mn, 0.40-1.0% Cr, 0.01-0.5% W, 0.08-0.30% of V, 0.005-0.25% of rare earth elements, and may further contain 0.001-0.10% of B. The alloy mainly adopts a low-carbon design, increasing the Si element content to improve the strength, and at the same time increasing the quenching hardenability of the steel with the W element, improving deformation resistance, and decarburization. elimination), but W and rare earth elements are relatively difficult to control for smelting and heat treatment.
중국 특허 CN1039725C는 자동차 서스펜션 스프링에 사용되는 저탈탄, 고인성 스프링강을 공개하였다. 이러한 강 중, C 함량이 감소되지 않은 상황에서 원소 Si의 함량을 높였으며, 0.5―0.7%의 C，1.0-3.5%의 Si，0.3-1.5%의 Mn，0.3-1.0%의 Cr，0.05-0.5%의 V 및/또는 Nb, 0.02% 미만의 P, 0.02% 미만의 S, 0.5-5.0%의 Ni와 기타 불가피한 불순물이고, 나머지는 Fe이다. 상기 재료는 탈탄 문제를 해결하고 인성을 개선하였으나, 비교적 많은 Ni 원소가 첨가되어 합금의 원가가 높다.Chinese patent CN1039725C discloses a low decarburization, high toughness spring steel used in automobile suspension springs. Among these steels, the content of elemental Si was increased when the C content was not reduced, and 0.5-0.7% of C, 1.0-3.5% of Si, 0.3-1.5% of Mn, 0.3-1.0% of Cr, 0.05- 0.5% V and/or Nb, less than 0.02% P, less than 0.02% S, 0.5-5.0% Ni and other unavoidable impurities, the remainder is Fe. The material solves the decarburization problem and improves toughness, but a relatively large amount of Ni is added, so the cost of the alloy is high.
종래의 합금기술방안은 주로 C, Si, Mn 원소의 조절을 통해 재료의 강도를 높이나, 지나치게 낮은 Si 함량은 재료의 탄성한계를 저하시켜 탄성 감쇠 저항(elasticity attenuation resistance)이 나빠지고, 지나치게 높은 Si 함량은 재료의 소성을 악화시킴과 동시에, 탈탄 제어의 난도를 증가시켜 스프링의 피로수명에 영향을 미칠 수 있다. 지나치게 높은 합금 원소의 첨가는 재료의 원가 상승을 초래함과 동시에 석출 크기에 영향을 미치고, 재료의 피로성능 저하를 초래할 수 있다. 재료의 설계 강도가 여전히 낮은 편이며, 또한 스프링의 피로수명에 대한 고려도 많지 않다. The conventional alloying technology plan mainly increases the strength of the material through the control of C, Si, and Mn elements, but an excessively low Si content lowers the elasticity limit of the material, resulting in poor elasticity attenuation resistance, and excessively high Si. The content may deteriorate the plasticity of the material and at the same time increase the difficulty of controlling decarburization, thereby affecting the fatigue life of the spring. The addition of an excessively high alloying element causes an increase in the cost of the material, and at the same time affects the precipitation size, and may lead to a decrease in the fatigue performance of the material. The design strength of the material is still low, and there are not many considerations for the fatigue life of the spring.
자동차의 경량화 발전 및 기계 업계의 기술 발전은 스프링 재료의 강도를 부단히 향상시키고 있으며, 현재 상용되는 Cr-V계, Cr-Mn계, Si-Mn계, Cr-Si계 스프링강은 모두 이미 재료의 한계에 도달하였다. Lightweight development of automobiles and technological advances in the machinery industry are constantly improving the strength of spring materials, and currently commercially available Cr-V series, Cr-Mn series, Si-Mn series, and Cr-Si series spring steels are The limit has been reached.
본 발명의 목적은 스프링강의 가공강도가 ≥2020MPa이고, 이와 동시에 양호한 소성과 인성(단면수축율이 ≥40%)을 지니며, 피로수명은 ≥80만회로, 자동차, 기계 등 업계의 고응력 스프링의 응용 수요를 충족시킬 수 있는 피로수명이 우수한 스프링강 및 그의 제조방법을 제공하고자 하는데 있다.The object of the present invention is that the processing strength of spring steel is ≥2020 MPa, and at the same time, it has good plasticity and toughness (cross-sectional shrinkage ratio of ≥40%), and the fatigue life is ≥800,000 circuits. It is intended to provide a spring steel with excellent fatigue life and a manufacturing method thereof that can meet the application demand.
상기 목적을 구현하기 위한 본 발명의 기술방안은 다음과 같다.The technical solution of the present invention for realizing the above object is as follows.
피로수명이 우수한 스프링강에 있어서, 그 화학성분의 중량백분율은 다음과 같다:For spring steel with excellent fatigue life, the weight percentage of its chemical composition is as follows:
C：0.52-0.62%；C: 0.52-0.62%;
Si：1.20-1.45%；Si:1.20-1.45%;
Mn：0.25-0.75%；Mn: 0.25-0.75%;
Cr：0.30-0.80%；Cr: 0.30-0.80%;
V：0.01-0.15%；V: 0.01-0.15%;
Nb：0.001-0.05%；Nb: 0.001-0.05%;
N：0.001-0.009%；N: 0.001-0.009%;
O：0.0005-0.0040%；O：0.0005-0.0040%;
P：≤0.015%；P: ≤0.015%;
S：≤0.015%；S: ≤0.015%;
Al：≤0.0045%이며;Al: ≤ 0.0045%;
나머지는 Fe와 불가피한 불순물이고, 또한 0.02≤(2Nb+V)/(20N+C)≤0.40을 동시에 만족시킨다. The remainder is Fe and inevitable impurities, and also satisfies 0.02≦(2Nb+V)/(20N+C)≦0.40 at the same time.
본 발명의 상기 스프링강의 현미경 조직은 템퍼드 투르스타이트(tempered troostite)+소르바이트(sorbite) 조직이며, 원 오스테나이트 결정입자의 크기는 ≤80um이고, 합금의 질탄 석출물 크기는 5-60um이며, 단일 입자 개재물(inclusion)의 최대 폭은 ≤30um이다.The microscopic structure of the spring steel of the present invention is a tempered troostite + sorbite structure, the size of the original austenite crystal grains is ≤80um, the size of the nitric coal precipitate of the alloy is 5-60um, and a single The maximum width of particle inclusions is ≤30um.
본 발명의 상기 스프링강의 성분 설계 중:In the component design of the spring steel of the present invention:
C는 스프링강의 실온강도와 ??칭 경화능을 보장하는데 필수적인 성분으로서, 스프링강이 높은 탄성한계, 양호한 탄성 감쇠 저항에 이르도록 하는 원소이다. C의 함량이 0.52% 미만인 경우, 상기 합금 스프링강의 강도는 2020MPa 이상을 보장할 수 없고, 이와 동시에 미량합금 원소의 탄질화물을 석출하기에 불리하나, 단 지나치게 높은 C의 함량은 템퍼링 과정에서 탄화물 크기가 지나치게 커지는 현상을 초래함과 동시에 재료의 소성을 악화시켜, 재료가 고강도 하에 양호한 소성 인성을 유지하기에 불리하여, 재료의 피로수명에 영향을 미친다. 따라서 C원소의 함량은 반드시 0.62%보다 낮아야 한다.C is an essential component to ensure the room temperature strength and quenching hardenability of spring steel, and is an element that enables spring steel to reach high elastic limit and good elastic damping resistance. When the content of C is less than 0.52%, the strength of the alloy spring steel cannot be guaranteed to be more than 2020 MPa, and at the same time, it is disadvantageous to precipitate carbonitrides of trace alloy elements, but an excessively high content of C is the size of carbides in the tempering process. At the same time, it causes a phenomenon in which is too large and deteriorates the plasticity of the material, which is unfavorable for the material to maintain good plastic toughness under high strength, and affects the fatigue life of the material. Therefore, the content of element C must be lower than 0.62%.
Si는 일종의 비탄화물 형성 원소로서, 주로 페라이트상에 고용되어 강화하는 역할을 한다. 합금 규소의 함량을 높이면 재료의 탄성한계 및 탄성 감쇠 저항을 높이기에 유리하고, 스프링의 성능을 최적화할 수 있으나, 단 지나치게 높은 Si 함량은 재료의 소성 악화를 초래하여 스프링의 성형에 불리하며, 제품의 스프링 수명에 영향을 미침과 동시에, Si 함량이 높으면 재료의 생산 및 열처리 과정에서 탈탄의 경향이 증가하여, 가공원가의 상승을 초래한다. 종합적으로 고려한 본 재료 중 Si 함량 제어 범위는 1.2-1.45%이다.Si is a kind of non-carbide-forming element, and mainly serves to strengthen and solidify in the ferrite phase. Increasing the content of silicon alloy is advantageous to increase the elastic limit and elastic damping resistance of the material, and the performance of the spring can be optimized. However, an excessively high Si content causes plasticity deterioration of the material, which is disadvantageous to the formation of the spring. In addition to affecting the spring life of the material, a high Si content increases the tendency of decarburization during the production and heat treatment of the material, leading to an increase in processing cost. The Si content control range in this material considered comprehensively is 1.2-1.45%.
Mn은 강 중 상용되는 첨가 원소로서, ??칭 경화능과 강도를 효과적으로 향상시킬 수 있고, 또한 강의 소성에 미치는 영향이 크지 않다. 합금의 강도 및 ??칭 경화능을 보장하기 위한 Mn 함량은 0.25%보다 낮아서는 안 된다. Mn의 함량 첨가량이 너무 많으면 심각한 편석(segregation)을 초래할 수 있고, 또한 결정입자가 커질 수 있다. 따라서 강 중의 Mn은 제어할 필요가 있으며, 허용 범위는 0.25-0.75%이다.Mn is a commonly used additive element in steel, and can effectively improve quenching hardenability and strength, and has little effect on the plasticity of steel. The Mn content to ensure the strength and quenching hardenability of the alloy should not be lower than 0.25%. If the amount of Mn added is too large, severe segregation may be caused, and crystal grains may also become large. Therefore, Mn in the steel needs to be controlled, and the allowable range is 0.25-0.75%.
Cr은 스프링강의 ??칭 경화능을 향상시킴과 동시에, 템퍼링 과정에서 합금 시멘타이트(Cementite)를 석출하여, 재료의 강도를 높이는 역할을 하고, Cr 원소는 또한 조직을 미세화하는 작용도 있다. 따라서 본 재료 설계에서 Cr의 고용 강화 및 석출 강화 작용을 발휘함과 동시에, 재료의 조직을 개선하기 위해 그 함량을 0.30-0.80%로 제어할 필요가 있다.Cr improves the quenching hardenability of spring steel, and at the same time, precipitates alloy cementite during the tempering process, thereby enhancing the strength of the material, and the Cr element also has a function to refine the structure. Therefore, in this material design, it is necessary to control the content to 0.30-0.80% in order to improve the structure of the material while exhibiting the solid solution strengthening and precipitation strengthening of Cr.
V, Nb 원소는 흔히 미량합금 원소로서 강에 첨가되며, 상기 두 원소는 강한 질화물과 탄화물 형성 경향을 지니고 있어, 템퍼링 과정에서 탄질화물 석출 핵생성률을 높이고, 조직을 미세화한다. V, Nb의 탄질화물은 선재 압연(wire rod rolling) 과정에서 석출되어, 재료의 오스테나이트 결정입도를 감소시키고, 재료의 강도와 소성을 높이기에 유리하다. 나노급의 석출물은 재료 강도의 증가, 소성 개선, 피로수명 향상에 대해 모두 장점이 있으며, 합금 중 V, Nb 함량의 첨가가 지나치게 많을 경우, 석출물의 크기가 증가할 수 있다. 두 원소 간의 상호 영향을 동시에 고려하고, 여러 번의 검증을 거친 결과, V의 첨가량은 0.01-0.15%로 제어하고, Nb의 함량은 0.001-0.05%로 제어하면 양호한 효과를 얻을 수 있다. N 함량의 증가는 재료의 취성 증가를 초래하며, N이 합금 원소의 석출에 미치는 작용을 동시에 고려하여, 강 중의 N은 0.001-0.009%로 제어해야 한다. 이와 동시에 석출물을 미세화하고자 하는 목적을 위해, 강 중(2Nb+V)/(20N+C)의 제어범위는 0.02-0.40이며, 0.045-0.37의 범위 내로 제어하는 것이 바람직하다. 일부 실시방안에서, 강 중의 (2Nb+V)/(20N+C)는 0.15-0.37의 범위 이내이다. 고강도, 양호한 소성 및 스프링 제품의 높은 피로수명을 달성하기 위하여, 경화 및 템퍼링 처리를 거친 후 재료의 원 오스테나이트 결정입자의 크기는 ≤80um이고, 강 중의 석출물 크기 제어 범위는 5-60nm이다.V and Nb elements are often added to steel as trace alloying elements, and the two elements have a strong tendency to form nitrides and carbides, thereby increasing the nucleation rate of carbonitride precipitation during the tempering process, and refinement of the structure. Carbonitrides of V and Nb are precipitated during wire rod rolling, which is advantageous in reducing the austenite grain size of the material and increasing the strength and plasticity of the material. Nano-grade precipitates have advantages in increasing material strength, improving plasticity, and improving fatigue life, and if the addition of V and Nb content in the alloy is excessive, the size of the precipitate may increase. Considering the mutual influence between the two elements at the same time, as a result of several verifications, good effects can be obtained if the amount of V added is controlled to 0.01-0.15% and the content of Nb is controlled to 0.001-0.05%. Increasing the N content causes an increase in the brittleness of the material, and taking into account the effect of N on the precipitation of alloying elements at the same time, the N in the steel should be controlled to 0.001-0.009%. At the same time, for the purpose of minimizing the precipitate, the control range of the steel (2Nb+V)/(20N+C) is 0.02-0.40, and it is preferable to control it within the range of 0.045-0.37. In some embodiments, (2Nb+V)/(20N+C) in the steel is within the range of 0.15-0.37. In order to achieve high strength, good plasticity and high fatigue life of spring products, the size of the raw austenite crystal grains of the material after hardening and tempering treatment is ≤80um, and the size control range of precipitates in the steel is 5-60nm.
Al은 강 중 주로 탈산소 작용을 하나, 단 Al의 탈산소로 형성된 산화알루미늄은 경취성상으로, 스프링의 피로수명에 미치는 영향이 비교적 크며, 큰 입자의 취성 개재물은 스프링의 비정상적인 단열을 초래하는 주요 요인 중 하나이다. 강 중 산화알루미늄 개재물의 효과적인 제어를 위해, 강 중 Al≤0.0045%이며, 산소의 함량 제어 범위는 0.0005-0.0040%이다. 스프링의 고강도 하의 피로수명을 높이기 위하여, 강 중 단일입자 개재물의 폭은 ≤30um으로 제어되어야 한다.Al mainly acts as a deoxidation among steels, but aluminum oxide formed by deoxygenation of Al is hard and brittle, and has a relatively large effect on the fatigue life of the spring, and brittle inclusions of large particles are the main cause of abnormal thermal insulation of the spring. It is one of the factors. For effective control of aluminum oxide inclusions in the steel, Al≤0.0045% in the steel, and the control range of the oxygen content is 0.0005-0.0040%. In order to increase the fatigue life of the spring under high strength, the width of single particle inclusions in the steel should be controlled to ≤30um.
재료의 인성을 보장하고, 생산 과정 중 열취성 및 냉취성 등 결함이 발행하는 것을 방지하기 위하여, 강 중 유해한 P, S 원소 함량을 각각 0.015%와 0.015% 이하로 제어하여 강질의 순정도를 높인다.In order to ensure the toughness of the material and prevent defects such as hot brittleness and cold brittleness during the production process, the content of harmful P and S elements in the steel is controlled to 0.015% and 0.015% or less, respectively, to increase the purity of the steel quality. .
본 발명의 상기 피로수명이 우수한 스프링강의 제조방법은, 제련, 연주, 조압연, 고속선재 압연, 스텔모어 제어 냉각(stelmor cooling), 선재 인발(wire rod drawing), ??칭 및 템퍼링 처리를 포함하며; 그 중,The manufacturing method of the spring steel having excellent fatigue life of the present invention includes smelting, casting, rough rolling, high-speed wire rolling, stellmor cooling, wire rod drawing, quenching and tempering treatment. And; among them,
상기 제련은 전기로 또는 전로(converter)를 이용하고, 제련 후 노외 정련을 실시하며, 노외 정련은 LF로에 VD 또는 RH 탈기 처리를 추가하고, LF 정련 과정에서 합성 슬래그의 조성과 알칼리도를 조정하며, 강 중 P, S 원소함량을 0.015% 및 0.015% 미만으로 제어하고, 아르곤가스 교반을 수행하여, 정련 슬래그와 용강 중의 개재물을 충분히 반응시키고 개재물의 변성 및 제거를 구현한다. VD 또는 RH 진공 탈기 시간은 30분 이상이어야 가스를 충분히 제거할 수 있으며, 종점의 O 함량은 0.0005-0.0040%로, N의 함량은 0.0010-0.0090%로, H의 함량은 2ppm 미만으로 제어한다. 정련이 종료된 래들(ladle)의 진정 시간이 15min 이상이면 큰 입자의 개재물이 떠오르도록 하기에 유리하며, 따라서 용강 중의 개재물 크기는 ≤30um으로 제어한다. The smelting uses an electric furnace or a converter, and after smelting, out-of-furnace refining is performed, and for out-of-furnace refining, VD or RH degassing treatment is added to the LF furnace, and the composition and alkalinity of the synthetic slag are adjusted in the LF refining process, The content of P and S elements in the steel is controlled to be less than 0.015% and 0.015%, and argon gas agitation is performed to sufficiently react the refined slag and the inclusions in the molten steel, and modify and remove the inclusions. The VD or RH vacuum degassing time must be 30 minutes or longer to sufficiently remove the gas, and the O content at the end point is 0.0005-0.0040%, the N content is 0.0010-0.0090%, and the H content is controlled to less than 2ppm. If the sedation time of the ladle after refining is more than 15 min, it is advantageous to allow large particles of inclusions to rise, and therefore, the size of the inclusions in molten steel is controlled to ≤30um.
상기 고속 선재 압연에서, 가열로의 가열은 920-1150℃로 제어하고, 보온 시간은 1.0-3.0h로 제어한다. 선재의 고속 압연 과정에서 압연 속도는 15-115m/s으로 제어하며; 온라인 온도 제어의 바람직한 방안은, 정밀 압연기의 주입구 온도가 880-1050℃이고, 리덕션 사이징밀(reducing sizing mill)의 주입구 온도는 840-970℃이며, 방사 온도(spinning temperature)는 800-950℃이다.In the high-speed wire rod rolling, the heating of the heating furnace is controlled at 920-1150°C, and the warming time is controlled at 1.0-3.0h. In the high-speed rolling process of the wire rod, the rolling speed is controlled at 15-115m/s; The preferred method of on-line temperature control is that the inlet temperature of the precision rolling mill is 880-1050°C, the inlet temperature of the reducing sizing mill is 840-970°C, and the spinning temperature is 800-950°C. .
바람직하게는, 연주기를 이용하여 원형 빌렛 또는 사각 빌렛을 주조하며, 원형 및 사각 빌렛의 크기는 320-500mm이다. 연주 과정 중의 인발 속도 범위를 0.5-0.8m/min로 조정하고 말단의 경압하량을 10mm 이상으로 조정하면, 빌렛 중심부의 탄소 편석을 1.08 미만으로 제어하는 목표를 달성할 수 있고; 용강의 주조 과정 중 2차 산화를 방지하는 동시에, 30um을 초과하는 큰 개재물의 부유 제거에 유리하다.Preferably, a circular billet or a square billet is cast using a caster, and the size of the round and square billets is 320-500mm. If the pulling speed range during the playing process is adjusted to 0.5-0.8 m/min and the light pressure load at the end is adjusted to 10 mm or more, the goal of controlling carbon segregation in the center of the billet to less than 1.08 can be achieved; It is advantageous in preventing the secondary oxidation during the casting process of molten steel and at the same time removing the floating of large inclusions exceeding 30um.
바람직하게는, 상기 조압연은 2단계 열처리 공정을 채택하며, 연주 빌렛을 1050-1270℃의 온도 하에 1차 압연하여 115-170mm의 사각, 원형 빌렛으로 분괴(cogging)하며, 압연의 총 압하량은 40%를 초과한다.Preferably, the rough rolling adopts a two-stage heat treatment process, and the billet is first rolled under a temperature of 1050-1270°C to cogging into square and circular billets of 115-170mm, and the total rolling reduction Exceeds 40%.
바람직하게는, 상기 선재 인발 시, 인발 속도는 3.5m/min를 초과하지 않는다.Preferably, when drawing the wire rod, the drawing speed does not exceed 3.5 m/min.
바람직하게는, 상기 ??칭 및 템퍼링 처리 중, 인발 강선의 ??칭 및 템퍼링 처리 전 가열 온도는 850-1100℃ 범위 내로 제어하고, ??칭 매질은 오일 또는 물을 이용하며, ??칭 매질의 온도는 15-40℃로 제어하고, 템퍼링 온도는 370-550℃로 제어함으로써, 완성품 강선 중 질탄 석출물의 크기를 5-60nm 범위 내로 제어한다.Preferably, during the quenching and tempering treatment, the heating temperature before quenching and tempering treatment of the drawn steel wire is controlled within the range of 850-1100°C, and oil or water is used as the quenching medium, and the quenching medium is quenched. The temperature of the medium is controlled at 15-40°C, and the tempering temperature is controlled at 370-550°C, thereby controlling the size of the coal precipitates in the finished steel wire within the range of 5-60 nm.
바람직하게는, 상기 스텔모어 냉각 중, 스텔모어 라인의 14대의 송풍기 풍량 조절 범위는 다음과 같다: F1-F7 송풍기의 풍량은 10-100%이고, F8-F12 송풍기의 풍량은 0-50%이며, F13-F14 송풍기의 풍량은 0-50%이다.Preferably, during the cooling of the stellmore, the air volume control range of the 14 blowers of the stellmore line is as follows: the air volume of the F1-F7 blowers is 10-100%, and the air volume of the F8-F12 blowers is 0-50%. , The air volume of the F13-F14 blowers is 0-50%.
본 발명의 상기 스프링강의 제조방법에 있어서,In the method for manufacturing the spring steel of the present invention,
상기 제련은 전기로 또는 전로를 이용하며, 제련 후 노외 정련을 실시한다. 노외 정련은 LF로에 VD 또는 RH 탈기 처리 공정을 추가하며, 전기로 또는 전로에서 출강 시 슬래그가 래들에 진입하는 것을 방지하고, LF 정련 과정에서 합성 슬래그의 조성과 알칼리도를 조절하며, 강 중 P, S 원소 함량을 0.015% 미만 및 0.015%로 제어하여 아르곤가스 교반을 실시함으로써, 정련 슬래그와 용강 중의 개재물을 충분히 반응시켜 개재물의 변성 및 제거를 구현한다. 가스가 충분히 제거되도록 보장하기 위해 VD 또는 RH 진공 탈기 시간은 30분 이상이어야 하며, 종점 O의 함량은 0.0005-0.0040%로, N의 함량은 0.0010-0.0090%로, H의 함량은 2ppm 미만으로 제어한다. 정련 종료 후 래들의 진정 시간이 15min 이상이면 큰 입자의 개재물이 부유하는데 유리하며, 강 중의 개재물은 ≤30um으로 제어한다.The smelting uses an electric furnace or a converter, and after smelting, out-of-furnace refining is performed. Out-of-furnace refining adds a VD or RH degassing treatment process to the LF furnace, prevents slag from entering the ladle when leaving the electric furnace or converter, and adjusts the composition and alkalinity of synthetic slag during the LF refining process, and P, By performing argon gas stirring by controlling the S element content to less than 0.015% and 0.015%, the refined slag and the inclusions in molten steel are sufficiently reacted to realize the denaturation and removal of the inclusions. VD or RH vacuum degassing time should be at least 30 minutes to ensure that the gas is sufficiently removed, and the content of the end point O is controlled to be 0.0005-0.0040%, the content of N is 0.0010-0.0090%, and the content of H is less than 2ppm. do. If the settling time of the ladle after refining is over 15min, it is advantageous for large particle inclusions to float, and the inclusion in the steel is controlled to ≤30um.
연주기를 이용하여 제련하는 합금에 대해 주조를 실시하여, 원형 빌렛 또는 사각 빌렛으로 주조할 수 있으며, 원형 및 사각 빌렛의 크기는 320-500mm이다. 연주 과정 중의 인발 속도 및 말단의 경압하 파라미터의 조정을 통해 빌렛 중심부의 탄소 편석을 1.08 미만으로 제어하는 목표를 달성할 수 있으며, 용강의 주조 과정 중 2차 산화를 방지하는 동시에, 30um을 초과하는 큰 개재물의 부유 제거에 유리하다. 2단계 열처리 공정을 채택하여, 연주 빌렛을 1050-1270℃의 온도하에 1차 압연시켜 115-170mm의 사각, 원형 빌렛으로 분괴(cogging)하며, 압연의 총 압하량은 40%를 초과하고, 조직이 미세화된다.Casting is performed on the alloy to be smelted using a caster, and it can be cast into round billets or square billets, and the sizes of round and square billets are 320-500mm. The goal of controlling the carbon segregation in the center of the billet to less than 1.08 can be achieved by adjusting the drawing speed during the playing process and the light pressure parameter at the end. It is advantageous for floating removal of large inclusions. By adopting a two-stage heat treatment process, the cast billet is first rolled under a temperature of 1050-1270℃ to cogging into 115-170mm square and round billets, and the total rolling reduction of rolling exceeds 40%, and the structure It becomes finer.
가열로의 가열은 920-1150℃로 제어하고, 보온 시간은 1.0-3.0h로 제어한다. 선재의 고속 압연 과정에서 압연 속도는 15-115m/s으로 제어하며; 온라인 온도 제어의 바람직한 방안은, 정밀 압연기의 주입구 온도가 880-1050℃이고, 리덕션 사이징밀(reducing sizing mill)의 주입구 온도는 840-970℃이며, 방사 온도(spinning temperature)는 800-950℃이다. 압연 과정의 온도 및 방사 온도의 조정을 통해, 재료의 원 오스테나이트 결정입자를 ≤80um으로 미세화하고, 이와 동시에 석출물의 크기 범위를 5-60nm으로 제어한다.The heating of the furnace is controlled at 920-1150°C, and the warming time is controlled at 1.0-3.0h. In the high-speed rolling process of the wire rod, the rolling speed is controlled at 15-115m/s; The preferred method of on-line temperature control is that the inlet temperature of the precision rolling mill is 880-1050°C, the inlet temperature of the reducing sizing mill is 840-970°C, and the spinning temperature is 800-950°C. . Through the adjustment of the temperature and spinning temperature in the rolling process, the raw austenite crystal grains of the material are refined to ≤ 80 μm, and at the same time, the size range of the precipitate is controlled to 5-60 nm.
압연 선재의 크기 규격은 Φ5-28mm이며, 선재는 압연 후 스텔모어 라인의 송풍기 풍량 조정을 통해 선재 조직의 변화를 제어한다. 스텔모어 라인의 14대의 송풍기 풍량 조정 범위는 다음과 같다: F1-F7 송풍기의 풍량은 10-100%이고, F8-F12 송풍기의 풍량은 0-50%이며, F13-F14 송풍기의 풍량은 0-50%이다. The size standard of the rolled wire rod is Φ5-28mm, and the change of the wire rod structure is controlled by adjusting the air volume of the blower of the Stelmore line after rolling. The air volume adjustment range of 14 blowers of the Stellmore line is as follows: the air volume of the F1-F7 blowers is 10-100%, the air volume of the F8-F12 blowers is 0-50%, and the air volume of the F13-F14 blowers is 0- 50%.
열처리 전 선재는 인발 처리를 수행해야 하며, 인발 시, 인발 속도는 3.5m/min을 초과하지 않도록 제어한다. 인발 강선의 ??칭 및 템퍼링 처리 전 가열 온도는 850-1100℃ 범위 내로 제어하고, ??칭 매질은 오일 또는 물을 이용하며, ??칭 매질의 온도는 15-40℃로 제어하고, 템퍼링 온도는 370-550℃로 제어함으로써, 완성품 강선 중 질탄 석출물의 크기를 5-60nm 범위 내로 제어한다.Before heat treatment, the wire rod must be subjected to a drawing treatment, and during drawing, the drawing speed is controlled so that it does not exceed 3.5m/min. The heating temperature before quenching and tempering treatment of the drawn steel wire is controlled within the range of 850-1100°C, oil or water is used as the quenching medium, and the temperature of the quenching medium is controlled to 15-40°C, and tempering. By controlling the temperature at 370-550°C, the size of the coal precipitates in the finished steel wire is controlled within the range of 5-60 nm.
본 발명의 강 성분과 제조방법으로 생산되는 스프링강은 강도가 2020MPa 이상에 달할 수 있으며, 상기 합금은 원가가 비교적 저렴하고, 나노급 석출물을 통해 재료를 강화시키는 동시에 양호한 소성과 인성을 구비하며, 우수한 스프링 성형 성능을 지녀 가공균열이 방지되고, 조직의 미세화 및 개재물 조성과 크기 제어를 통해 완제품 스프링은 높은 피로수명을 구비하여, 자동차의 경량화와 기계업계의 고강도 및 긴 수명의 사용 요구를 충족시킬 수 있으며, 업계의 기술 수준을 높이기에 유리하고, 양호한 경제적 효익을 지닌다.The strength of the spring steel produced by the steel component and manufacturing method of the present invention may reach 2020 MPa or more, and the alloy is relatively inexpensive, and the material is reinforced through nano-grade precipitates while providing good plasticity and toughness, With excellent spring forming performance, processing cracks are prevented, and the finished product spring has a high fatigue life through microstructure and inclusion composition and size control, which can meet the demands of lightweight automobiles and high strength and long life in the machinery industry. It is advantageous to increase the technology level of the industry, and has good economic benefits.
본 발명의 실시예 A1-10# 및 3개의 비교 강종 B1-3#의 화학 성분은 하기 표 1과 같으며, 구체적인 제조방법은 다음과 같다:Chemical components of Examples A1-10# and three comparative steel grades B1-3# of the present invention are shown in Table 1 below, and a specific manufacturing method is as follows:
본 발명의 실시예 A1-5#, 비교 강종 B1, B2 합금은 전기로 제련을 이용하고, 실시예 A6-10#, 비교 강종 B3 합금은 전로 제련을 이용하며, 이후 노외 정련을 실시하였다. 그 중 실시예 A1-3#, A6-8#, B1 합금은 LF로에 VD 정련을 추가하였으며, 실시예 A4-5#, A9-10#, B2, B3 합금은 LF에 RH 처리를 추가하여, 합성 슬래그 조직과 알칼리도를 최적화하였고, A1-6#, B1의 진공 탈기 시간은 30분이며, A7-10#, B2, B3의 진공탈기 시간은 35분이고, 종점의 O 함량은 0.0005-0.0040%이며, N의 함량은 N:0.001-0.009%이고, H의 함량은 2ppm 미만으로 제어하였다.Examples A1-5# of the present invention, comparative steel types B1, and B2 alloys use electric furnace smelting, and Examples A6-10# and comparative steel type B3 alloys use converter smelting, and then out-of-furnace refining was performed. Among them, Examples A1-3#, A6-8#, and B1 alloys added VD refining to the LF furnace, and Examples A4-5#, A9-10#, B2, and B3 alloys added RH treatment to LF, Synthetic slag structure and alkalinity were optimized, and the vacuum degassing time of A1-6# and B1 is 30 minutes, the vacuum degassing time of A7-10#, B2, and B3 is 35 minutes, and the O content at the end point is 0.0005-0.0040%. , The content of N was N: 0.001-0.009%, and the content of H was controlled to be less than 2ppm.
제련이 종료된 후, A1-4#, B1은 300mm의 원형 빌렛으로 주조하고, A5-6#은 450mm의 원형 빌렛으로 주조하였으며, A7-9#, B2는 320*420mm 사각 빌렛으로 주조하고, A10#, B3은 500 사각 빌렛으로 주조하였다. 주조 과정에서 밀봉성이 양호한 턴디쉬 커버 플럭스(tundish cover flux)와 몰드 플럭스(Mold Flux)를 사용하였다. A1-5#, B1 연주 빌렛의 초기 압연의 분괴(cogging) 온도는 1050℃이고, 압연한 소형 사각 빌렛의 끝단면 크기는 115mm이다. A6-7#, B2 사각 빌렛의 가열 온도는 1270℃이고, 압연한 빌렛의 크기는 125mm이다. A8-10#, B3 사각 빌렛의 가열 온도는 1100℃이고, 압연 빌렛의 크기는 170mm이다.After the smelting was completed, A1-4# and B1 were cast into 300mm round billets, A5-6# were cast into 450mm round billets, and A7-9# and B2 were cast into 320*420mm square billets, A10# and B3 were cast into 500 square billets. In the casting process, a tundish cover flux and a mold flux having good sealing properties were used. The cogging temperature of the initial rolling of A1-5# and B1 cast billets was 1050°C, and the size of the end face of the rolled small square billets was 115 mm. The heating temperature of the A6-7#, B2 square billet is 1270°C, and the size of the rolled billet is 125mm. The heating temperature of the A8-10#, B3 square billet is 1100°C, and the size of the rolled billet is 170 mm.
A1-4#, B1 가열로의 온도는 920℃로 제어하고, 보온 시간은 1.0h로 제어하였으며, A5-10#, B2, B3 가열로의 온도는 1150℃로, 보온 시간은 3.0h로 제어하였다. 선재의 고속 압연 과정에서 압연 속도를 15-115m/s로 제어하였다. 온라인 온도 제어 방안에서, A1-6#, B1 합금 정밀압연기의 주입구 온도는 880-950℃이고, 리덕션 사이징밀(reducing sizing mill)의 주입구 온도는 840-950℃이며, 방사 온도(spinning temperature)는 800-890℃이다. A7-10#, B2, B3 합금 정밀압연기의 주입구 온도는 950-1050℃이고, 리덕션 사이징밀의 주입구 온도는 940-970℃이며, 방사 온도는 870-950℃이다.The temperature of the heating furnace A1-4# and B1 was controlled at 920℃, and the warming time was controlled at 1.0h, the temperature of the heating furnaces A5-10#, B2, and B3 was controlled at 1150℃, and the warming time was controlled at 3.0h. I did. In the high-speed rolling process of the wire rod, the rolling speed was controlled to 15-115 m/s. In the online temperature control scheme, the inlet temperature of the A1-6#, B1 alloy precision rolling machine is 880-950℃, the inlet temperature of the reducing sizing mill is 840-950℃, and the spinning temperature is It is 800-890°C. The inlet temperature of the A7-10#, B2, B3 alloy precision rolling mill is 950-1050℃, the inlet temperature of the reduction sizing mill is 940-970℃, and the spinning temperature is 870-950℃.
그 중, A1-5#, B1, B2 합금 압연 선재의 크기 규격은 각각 φ5-15mm이고, A6-10#, B3 합금 선재의 압연 규격은 φ16-28mm이다. A1-5#, B1 합금 선재의 압연 후 스텔모어 냉각 공정은 다음과 같다: F1-F4 송풍기의 풍량은 40%이고, F5-F7 송풍기의 풍량은 10%이며, F8-F12 송풍기의 풍량은 5%이고, F13-F14 송풍기의 풍량은 40%이다. A6-10#, B2, B3 합금 선재의 압연 후 스텔모어 냉각 공정은 다음과 같다: F1-F4 송풍기의 풍량은 50%이고, F5-F7 송풍기의 풍량은 20%이며, F8-F12 송풍기의 풍량은 15%이고, F13-F14 송풍기의 풍량은 35%이다. 스텔모어 냉각을 거친 후 선재 조직에 소르바이트(sorbite)에 극소량의 페라이트(Ferrite)가 첨가되었다.Among them, the size specifications of the A1-5#, B1, and B2 alloy rolled wires are φ5-15mm, respectively, and the rolled specifications of the A6-10# and B3 alloy wires are φ16-28mm. After rolling the A1-5#, B1 alloy wire rod, the cooling process of Stelmore is as follows: The air volume of the F1-F4 blower is 40%, the air volume of the F5-F7 blower is 10%, and the air volume of the F8-F12 blower is 5 %, and the air volume of the blowers F13-F14 is 40%. After rolling the A6-10#, B2, and B3 alloy wire rods, the cooling process of Stelmore is as follows: The air volume of the F1-F4 blower is 50%, the air volume of the F5-F7 blower is 20%, and the air volume of the F8-F12 blower Is 15%, and the air volume of the blowers F13-F14 is 35%. After cooling of Stellemore, a very small amount of ferrite was added to sorbite to the wire structure.
열처리 전 선재에 대해 인발 처리를 수행하였으며, 인발 강선의 ??칭 및 템퍼링 처리 온도는 3그룹으로 구분하였다. 그 중 A1-2#, B1의 가열 온도는 850℃이고, 템퍼링 온도는 550℃이며, A3-7#, B2의 가열 온도는 980℃이고, 템퍼링 온도는 470℃이며, A8-10#, B3의 가열 온도는 1100℃이고, 템퍼링 온도는 370℃이다.Before the heat treatment, the wire rod was subjected to a drawing treatment, and the temperature of the drawn steel wire was divided into three groups. Among them, the heating temperature of A1-2# and B1 is 850℃, the tempering temperature is 550℃, the heating temperature of A3-7# and B2 is 980℃, the tempering temperature is 470℃, and A8-10#, B3 The heating temperature of is 1100°C, and the tempering temperature is 370°C.
실시예 A1-A10의 고강도 스프링 및 비교 강종 B1-B3의 역학 성능은 하기 표 2에 나타낸 바와 같다. 표를 통해 합금 강도가 모두 2020MPa 이상에 달하여, 비교예인 B1-B3 샘플보다 높고, 또한 재료의 단면수축율이 여전히 40% 이상에 달하여 양호한 소성 및 인성의 결합을 갖는 것을 볼 수 있다. 본 발명의 고강도 스프링과 비교 합금으로 동일 모델의 나선 스프링을 제조하였으며, 스프링 피로 시험기를 이용하여 GBT16947-2009 나선 스프링 피로시험 규범에 따라 나선 스프링에 대해 피로수명 검출을 실시하였다. 결과는 표3과 같으며, 동일한 조건 하에, 본 발명의 고강도 스프링강의 피로수명이 비교 강종보다 우수한 것으로 나타났다.The mechanical performances of the high strength springs of Examples A1-A10 and the comparative steel grades B1-B3 are shown in Table 2 below. From the table, it can be seen that all of the alloy strengths reached 2020 MPa or more, higher than that of the comparative example B1-B3 sample, and the cross-sectional shrinkage of the material still reached 40% or more, thereby having a good combination of plasticity and toughness. A spiral spring of the same model was manufactured from the high strength spring of the present invention and a comparative alloy, and fatigue life detection was performed on the spiral spring according to the GBT16947-2009 spiral spring fatigue test standard using a spring fatigue tester. The results are shown in Table 3, and under the same conditions, it was found that the fatigue life of the high-strength spring steel of the present invention was superior to that of the comparative steel type.
표 1: 본 발명의 실시예 A1-10#과 비교 강종 B1-3#의 화학성분(wt%)Table 1: Chemical composition (wt%) of Example A1-10# of the present invention and comparative steel grade B1-3#
번호River
number
표 2: 본 발명의 합금강 조직Table 2: Structure of alloy steel of the present invention
결정입자 크기
（um）One austenite
Grain size
（Um）
（nm）Size of coal deposits
（Nm）
（um）Maximum width of single particle inclusions
（Um）
표 3: 본 발명의 합금강 실시예 및 비교 강종 성능Table 3: Alloy steel examples and comparative steel grade performance of the present invention
MPaThe tensile strength
MPa
%Sectional shrinkage rate
%
회Fatigue life
time
Claims (9)
그 화학성분의 중량백분율은
C：0.52-0.62%；
Si：1.20-1.45%；
Mn：0.25-0.75%；
Cr：0.30-0.80%；
V：0.01-0.15%；
Nb：0.001-0.05%；
N：0.001-0.009%；
O：0.0005-0.0040%；
P：≤0.015%；
S：≤0.015%；
Al：≤0.0045%이고;
나머지는 Fe와 불가피한 불순물이며, 또한 0.02≤(2Nb+V)/(20N+C)≤0.40을 동시에 만족시키는 것을 특징으로 하는 피로수명이 우수한 탄소강.In carbon steel with excellent fatigue life,
The weight percentage of the chemical component is
C: 0.52-0.62%;
Si:1.20-1.45%;
Mn: 0.25-0.75%;
Cr: 0.30-0.80%;
V: 0.01-0.15%;
Nb: 0.001-0.05%;
N: 0.001-0.009%;
O：0.0005-0.0040%;
P: ≤0.015%;
S: ≤0.015%;
Al: ≤ 0.0045%;
The remainder is Fe and unavoidable impurities, and also satisfies 0.02≦(2Nb+V)/(20N+C)≦0.40 at the same time, and has excellent fatigue life.
상기 스프링강의 현미경 조직은 템퍼드 투르스타이트(tempered troostite)+소르바이트(sorbite) 조직이며, 원 오스테나이트 결정입자의 크기는 ≤80um이고, 합금의 질탄 석출물 크기는 5-60um이며, 단일 입자 개재물(inclusion)의 최대 폭은 ≤30um인 것을 특징으로 하는 피로수명이 우수한 탄소강.The method of claim 1,
The microscopic structure of the spring steel is a tempered troostite + sorbite structure, the size of the original austenite crystal grain is ≤80um, the size of the nitric coal precipitate of the alloy is 5-60um, and the single grain inclusions ( Carbon steel with excellent fatigue life, characterized in that the maximum width of inclusion) is ≤30um.
상기 스프링강의 가공강도는 ≥2020MPa이고, 단면수축율은 ≥40%이며, 피로수명은 ≥80만회인 것을 특징으로 하는 피로수명이 우수한 탄소강.The method according to claim 1 or 2,
Carbon steel having excellent fatigue life, characterized in that the processing strength of the spring steel is ≥2020 MPa, the cross-sectional shrinkage rate is ≥40%, and the fatigue life is ≥800,000 times.
상기 제련은 전기로 또는 전로(converter)를 이용하고, 제련 후 노외 정련을 실시하며, 노외 정련은 LF로에 VD 또는 RH 탈기 처리를 추가하고, LF 정련 과정에서 합성 슬래그의 조성과 알칼리도를 조정하며, 강 중 P, S 원소함량을 0.015% 및 0.015% 미만으로 제어하고, 아르곤가스 교반을 수행하여, 정련 슬래그와 용강 중의 개재물을 충분히 반응시키고 개재물의 변성 및 제거를 구현하며; VD 또는 RH 진공 탈기 시간은 30분 이상이고, 종점의 O 함량은 0.0005-0.0040%로, N의 함량은 0.0010-0.0090%로, H의 함량은 2ppm 미만으로 제어하며; 정련이 종료된 래들(ladle)의 진정 시간은 큰 입자의 개재물이 떠오르기에 유리하도록 15min 이상으로 하고, 용강 중의 개재물 크기는 ≤30um으로 제어하며;
상기 고속 선재 압연에서, 가열로의 가열은 920-1150℃로 제어하고, 보온 시간은 1.0-3.0h이며, 선재의 고속 압연 과정에서 압연 속도는 15-115m/s으로 제어하며; 온라인 온도 제어의 바람직한 방안은, 정밀 압연기의 주입구 온도가 880-1050℃이고, 리덕션 사이징밀(reducing sizing mill)의 주입구 온도는 840-970℃이며, 방사 온도(spinning temperature)는 800-950℃인 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.In a manufacturing method including smelting, rolling, rough rolling, high-speed wire rolling, stellmore control cooling, wire drawing, quenching and tempering treatment of carbon steel having excellent fatigue life according to claim 1 or 2 or 3 In,
The smelting uses an electric furnace or a converter, and after smelting, out-of-furnace refining is performed.For out-of-furnace refining, VD or RH degassing treatment is added to the LF furnace, and the composition and alkalinity of synthetic slag are adjusted in the LF refining process Control the content of P and S elements in the steel to less than 0.015% and less than 0.015%, and perform argon gas stirring to sufficiently react the refining slag and the inclusions in the molten steel, and to realize the modification and removal of the inclusions; VD or RH vacuum degassing time is 30 minutes or more, the O content at the end point is controlled to be 0.0005-0.0040%, the content of N is 0.0010-0.0090%, and the content of H is less than 2ppm; The settling time of the ladle after the refining is completed is 15 min or more so as to be advantageous for the rise of large particle inclusions, and the size of the inclusions in molten steel is controlled to ≤ 30 μm;
In the high-speed wire rod rolling, the heating of the heating furnace is controlled at 920-1150°C, the heat retention time is 1.0-3.0h, and the rolling speed is controlled at 15-115m/s in the high-speed rolling process of the wire rod; The preferred method of online temperature control is that the inlet temperature of the precision rolling mill is 880-1050°C, the inlet temperature of the reducing sizing mill is 840-970°C, and the spinning temperature is 800-950°C. Method for producing carbon steel having excellent fatigue life, characterized in that.
연주기를 이용하여 원형 빌렛 또는 사각 빌렛을 주조하고, 원형 및 사각 빌렛의 크기는 320-500mm이며, 연주 과정 중의 인발 속도 범위를 0.5-0.8m/min로 조정하고 말단의 경압하량을 10mm 이상으로 조정하여, 빌렛 중심부의 탄소 편석을 1.08 미만으로 제어하는 목표를 달성하는 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.The method of claim 4,
Cast circular billets or square billets using a caster, and the size of round and square billets is 320-500mm, and the pulling speed range during the playing process is adjusted to 0.5-0.8m/min, and the light pressure load at the end is 10mm or more. By adjusting, the carbon steel production method having excellent fatigue life, characterized in that to achieve the goal of controlling the carbon segregation in the center of the billet to less than 1.08.
상기 조압연은 2단계 열처리 공정을 채택하며, 연주 빌렛을 1050-1270℃의 온도 하에 1차 압연하여 115-170mm의 사각, 원형 빌렛으로 분괴(cogging)하며, 압연의 총 압하량은 40%를 초과하는 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.The method of claim 4,
The rough rolling adopts a two-stage heat treatment process, and the cast billet is first rolled at a temperature of 1050-1270°C to cogging into 115-170mm square and circular billets, and the total rolling reduction is 40%. A method for producing carbon steel having excellent fatigue life, characterized in that it exceeds.
상기 선재 인발 시, 인발 속도는 3.5m/min를 초과하지 않는 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.The method of claim 4,
When drawing the wire rod, the method of manufacturing carbon steel having excellent fatigue life, characterized in that the drawing speed does not exceed 3.5 m/min.
상기 ??칭 및 템퍼링 처리 중, 인발 강선의 ??칭 및 템퍼링 처리 전 가열 온도는 850-1100℃ 범위 내로 제어하고, ??칭 매질은 오일 또는 물을 이용하며, ??칭 매질의 온도는 15-40℃로 제어하고, 템퍼링 온도는 370-550℃로 제어함으로써, 완성품 강선 중 질탄 석출물의 크기를 5-60nm 범위 내로 제어하는 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.The method of claim 4,
During the quenching and tempering treatment, the heating temperature of the drawn steel wire before quenching and tempering treatment is controlled within the range of 850-1100°C, oil or water is used as the quenching medium, and the temperature of the quenching medium is A method of manufacturing carbon steel having excellent fatigue life, characterized in that the size of the coal precipitates in the finished steel wire is controlled within the range of 5-60 nm by controlling the temperature at 15-40°C and the tempering temperature at 370-550°C.
상기 스텔모어 냉각 중, 스텔모어 라인의 14대의 송풍기 풍량 조절 범위는 다음과 같다: F1-F7 송풍기의 풍량은 10-100%이고, F8-F12 송풍기의 풍량은 0-50%이며, F13-F14 송풍기의 풍량은 0-50%인 것을 특징으로 하는 피로수명이 우수한 탄소강의 제조방법.
The method of claim 4,
During the cooling of the stellmore, the air volume control range of the 14 blowers of the stellmore line is as follows: the air volume of the blowers F1-F7 is 10-100%, the air volume of the blowers F8-F12 is 0-50%, and the F13-F14 A method of manufacturing carbon steel having excellent fatigue life, characterized in that the air volume of the blower is 0-50%.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810842312.5A CN110760748B (en) | 2018-07-27 | 2018-07-27 | Spring steel with excellent fatigue life and manufacturing method thereof |
| CN201810842312.5 | 2018-07-27 | ||
| PCT/CN2019/096726 WO2020020066A1 (en) | 2018-07-27 | 2019-07-19 | Spring steel having superior fatigue life, and manufacturing method for same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20210036916A true KR20210036916A (en) | 2021-04-05 |
Family
ID=69182026
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020217001643A KR20210036916A (en) | 2018-07-27 | 2019-07-19 | Spring steel with excellent fatigue life and its manufacturing method |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US20210164078A1 (en) |
| EP (1) | EP3831970B1 (en) |
| JP (1) | JP7110480B2 (en) |
| KR (1) | KR20210036916A (en) |
| CN (1) | CN110760748B (en) |
| WO (1) | WO2020020066A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022255727A1 (en) * | 2021-06-02 | 2022-12-08 | 포스코홀딩스 주식회사 | Wire rod and steel wire for spring, spring with improved strength and fatigue limit, and method for manufacturing same |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101416811B1 (en) * | 2012-12-28 | 2014-08-06 | 비나텍주식회사 | Apparatus for attaching electrode and method for manufacturing super capacitor using the same |
| CN113322410B (en) * | 2020-02-28 | 2022-06-28 | 宝山钢铁股份有限公司 | High-strength bolt steel with excellent delayed fracture resistance and preparation method thereof |
| CN111763892A (en) * | 2020-07-31 | 2020-10-13 | 南京钢铁股份有限公司 | High-strength and high-toughness spring steel wire rod and preparation method thereof |
| CN112792122A (en) * | 2020-11-23 | 2021-05-14 | 邯郸钢铁集团有限责任公司 | Production method of direct cold-drawing spring steel wire with low cost and excellent comprehensive performance |
| KR102531464B1 (en) * | 2020-12-18 | 2023-05-12 | 주식회사 포스코 | Steel wire rod, steel wire, and manufacturing method thereof for ultra-high strength springs |
| CN115433871B (en) * | 2021-06-02 | 2023-07-07 | 宝山钢铁股份有限公司 | High-strength steel resistant to hydrogen embrittlement delayed fracture and manufacturing method thereof |
| CN113881897A (en) * | 2021-09-29 | 2022-01-04 | 东莞市锦中秀寝具用品有限公司 | High-strength alloy material for spring and high-strength spring |
| CN113969375B (en) * | 2021-10-29 | 2022-04-26 | 建龙北满特殊钢有限责任公司 | Preparation method of sulfur-containing and aluminum-containing steel |
| CN114150107A (en) * | 2021-11-26 | 2022-03-08 | 南京钢铁股份有限公司 | Smelting method of spring steel for ultrahigh-strength engineering machinery |
| CN114622126A (en) * | 2022-03-11 | 2022-06-14 | 江阴兴澄合金材料有限公司 | Spring steel wire rod for ultrahigh-strength steel wire and manufacturing method thereof |
| CN114807552B (en) * | 2022-03-21 | 2023-09-15 | 江阴兴澄合金材料有限公司 | Production method of spring steel hot-rolled wire rod |
| CN114921709A (en) * | 2022-03-24 | 2022-08-19 | 南京钢铁股份有限公司 | Preparation method of high-strength and high-toughness spring steel wire rod |
| CN114769351A (en) * | 2022-03-30 | 2022-07-22 | 厦门立洲五金弹簧有限公司 | Manufacturing process of high-stress spring |
| CN115125446A (en) * | 2022-06-28 | 2022-09-30 | 浙江伊思灵双第弹簧有限公司 | High-fatigue-performance spring for automobile and preparation method thereof |
| CN114807728B (en) * | 2022-06-30 | 2022-11-18 | 江苏省沙钢钢铁研究院有限公司 | 2100MPa grade spring steel wire and production method thereof |
| CN115141978A (en) * | 2022-07-26 | 2022-10-04 | 常熟市龙腾特种钢有限公司 | Steel ingot for marine diesel engine connecting rod forging and production method thereof |
| CN115386680B (en) * | 2022-08-15 | 2023-09-12 | 马鞍山钢铁股份有限公司 | Method for precisely controlling content of molten steel [ Al ] at end point of LF furnace |
| CN116516267B (en) * | 2023-03-21 | 2024-03-29 | 王平 | Solid solution and nano-reinforced sorbite high-strength stainless structural steel and preparation method thereof |
| CN117230376B (en) * | 2023-11-10 | 2024-03-05 | 钢铁研究总院有限公司 | Electrode for producing 300M steel and preparation method and application thereof |
Family Cites Families (36)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4711675A (en) * | 1981-08-11 | 1987-12-08 | Aichi Steel Works, Ltd. | Process for improving the sag-resistance and hardenability of a spring steel |
| JPS60116720A (en) * | 1983-11-28 | 1985-06-24 | Sumitomo Metal Ind Ltd | Manufacture of spring having superior sag resistance |
| KR960005230B1 (en) * | 1993-12-29 | 1996-04-23 | 포항종합제철주식회사 | Making method of high strength high tension spring steel |
| JP3595901B2 (en) | 1998-10-01 | 2004-12-02 | 鈴木金属工業株式会社 | High strength steel wire for spring and manufacturing method thereof |
| JP3601388B2 (en) * | 1999-12-17 | 2004-12-15 | 住友金属工業株式会社 | Method of manufacturing steel wire and steel for steel wire |
| JP3971571B2 (en) | 2000-12-20 | 2007-09-05 | 新日本製鐵株式会社 | Steel wire for high strength spring |
| KR100514120B1 (en) | 2000-12-20 | 2005-09-13 | 신닛뽄세이테쯔 카부시키카이샤 | High-strength spring steel and spring steel wire |
| JP3633866B2 (en) | 2000-12-28 | 2005-03-30 | 住友電工スチールワイヤー株式会社 | Steel wire for spring, spring and manufacturing method thereof |
| JP3763573B2 (en) * | 2002-11-21 | 2006-04-05 | 三菱製鋼株式会社 | Spring steel with improved hardenability and pitting corrosion resistance |
| CN1764733A (en) * | 2003-03-28 | 2006-04-26 | 株式会社神户制钢所 | Steel for spring being excellent in resistance to setting and fatigue characteristics |
| CN1279204C (en) | 2003-08-27 | 2006-10-11 | 宝山钢铁股份有限公司 | High utilization stress spring steel for automobile |
| JP4423254B2 (en) | 2005-12-02 | 2010-03-03 | 株式会社神戸製鋼所 | High strength spring steel wire with excellent coiling and hydrogen embrittlement resistance |
| JP4027956B2 (en) * | 2006-01-23 | 2007-12-26 | 株式会社神戸製鋼所 | High strength spring steel having excellent brittle fracture resistance and method for producing the same |
| JP4310359B2 (en) * | 2006-10-31 | 2009-08-05 | 株式会社神戸製鋼所 | Steel wire for hard springs with excellent fatigue characteristics and wire drawability |
| JP4163239B1 (en) * | 2007-05-25 | 2008-10-08 | 株式会社神戸製鋼所 | High cleanliness spring steel and high cleanliness spring with excellent fatigue characteristics |
| CN101397629B (en) * | 2007-09-26 | 2010-09-08 | 南京依维柯汽车有限公司 | High intensity variable section spring piece under high stress and method for producing the same |
| CN101717894A (en) * | 2009-12-15 | 2010-06-02 | 南京钢铁股份有限公司 | 40Si2MnCrNiMoVNbN spring steel and production process thereof |
| CN101717893B (en) * | 2009-12-15 | 2012-08-22 | 南京钢铁股份有限公司 | 55Si2MnVNbN spring steel and production process thereof |
| CN101787493B (en) | 2010-01-25 | 2011-07-20 | 广州市奥赛钢线科技有限公司 | Novel high-strength, fatigue-resistant and non-decarburized alloy spring steel and preparation method of steel wire thereof |
| JP5476597B2 (en) * | 2010-03-04 | 2014-04-23 | 株式会社神戸製鋼所 | Seamless steel pipe for high-strength hollow springs |
| CN103415637B (en) | 2011-03-01 | 2014-08-06 | 新日铁住金株式会社 | High-carbon steel wire having excellent drawability and fatigue properties after drawing |
| BR112014003415B1 (en) * | 2011-08-18 | 2019-05-28 | Nippon Steel & Sumitomo Metal Corporation | STEEL FOR SPRING AND SPRING |
| CN102634730B (en) * | 2012-04-28 | 2014-10-29 | 宝山钢铁股份有限公司 | Steel wire rod for 1860MPa-level bridge cable galvanized steel wire and manufacturing method thereof |
| KR101449111B1 (en) * | 2012-08-09 | 2014-10-08 | 주식회사 포스코 | Steel wire rod having excellent strength and ductility and method for manufacturing the same |
| AT512399B1 (en) * | 2012-09-10 | 2013-08-15 | Siemens Vai Metals Tech Gmbh | Method for producing a microalloyed tubular steel in a cast-rolled composite plant and microalloyed tubular steel |
| CN103045935B (en) * | 2012-12-14 | 2014-12-03 | 天津钢铁集团有限公司 | Control method for surface decarburization and ferrite distribution of steel disc bar of spring |
| US10350676B2 (en) * | 2013-04-23 | 2019-07-16 | Nippon Steel & Sumitomo Metal Corporation | Spring steel with excellent fatigue resistance and method of manufacturing the same |
| CN103484781B (en) * | 2013-09-26 | 2016-06-01 | 宝山钢铁股份有限公司 | A kind of high-strength and high-ductility spring steel and manufacture method thereof |
| CN104046903B (en) * | 2014-06-30 | 2017-01-11 | 宝山钢铁股份有限公司 | Coil rod for Grade 13.9/Grade 14.9 delayed-fracture-resistant high-strength fasteners and manufacturing method thereof |
| JP6354481B2 (en) | 2014-09-12 | 2018-07-11 | 新日鐵住金株式会社 | Steel wire and method for manufacturing steel wire |
| KR101745191B1 (en) * | 2015-12-04 | 2017-06-09 | 현대자동차주식회사 | Ultra high strength spring steel |
| KR101745196B1 (en) * | 2015-12-07 | 2017-06-09 | 현대자동차주식회사 | Ultra high strength spring steel |
| CN105648338A (en) * | 2016-01-27 | 2016-06-08 | 太仓捷公精密金属材料有限公司 | Automotive high-performance spring steel |
| CN105886930B (en) * | 2016-04-26 | 2017-12-26 | 宝山钢铁股份有限公司 | A kind of high-strength corrosion-resistant spring steel and its manufacture method |
| KR20180074008A (en) * | 2016-12-23 | 2018-07-03 | 주식회사 포스코 | Steel wire rod having excellent hydrogen embrittlement resistance for high strength spring, and method for manufacturing the same |
| CN107747060A (en) * | 2017-11-12 | 2018-03-02 | 湖南华菱湘潭钢铁有限公司 | The production method of high intensity high fatigue life spring steel |
-
2018
- 2018-07-27 CN CN201810842312.5A patent/CN110760748B/en active Active
-
2019
- 2019-07-19 EP EP19841872.5A patent/EP3831970B1/en active Active
- 2019-07-19 US US17/261,457 patent/US20210164078A1/en not_active Abandoned
- 2019-07-19 JP JP2021503062A patent/JP7110480B2/en active Active
- 2019-07-19 WO PCT/CN2019/096726 patent/WO2020020066A1/en unknown
- 2019-07-19 KR KR1020217001643A patent/KR20210036916A/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022255727A1 (en) * | 2021-06-02 | 2022-12-08 | 포스코홀딩스 주식회사 | Wire rod and steel wire for spring, spring with improved strength and fatigue limit, and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110760748B (en) | 2021-05-14 |
| JP2021530623A (en) | 2021-11-11 |
| US20210164078A1 (en) | 2021-06-03 |
| EP3831970B1 (en) | 2023-05-10 |
| WO2020020066A1 (en) | 2020-01-30 |
| EP3831970A4 (en) | 2021-06-09 |
| EP3831970A1 (en) | 2021-06-09 |
| CN110760748A (en) | 2020-02-07 |
| JP7110480B2 (en) | 2022-08-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR20210036916A (en) | Spring steel with excellent fatigue life and its manufacturing method | |
| JP4381355B2 (en) | Steel having excellent delayed fracture resistance and tensile strength of 1600 MPa class or more and method for producing the molded product thereof | |
| CN112048665B (en) | Steel plate for polar region ocean engineering and preparation method thereof | |
| CN109161803B (en) | 1550 MPa-grade spring flat steel and production method thereof | |
| CN111394639B (en) | Manufacturing method of high-wear-resistance gear steel | |
| CN113388773B (en) | 1.5GPa grade high-formability hydrogen-embrittlement-resistant ultrahigh-strength automobile steel and preparation method thereof | |
| KR20130076570A (en) | Ultra heavy steel plate for pressure vessel with excellent low-temperature toughness and tensile property and manufacturing method of the same | |
| CN108342649B (en) | Acid corrosion resistant quenched and tempered high-strength steel for pressure vessel and production method thereof | |
| WO2021057954A9 (en) | Steel for alloy structure and manufacturing method therefor | |
| CN110592480A (en) | Thick Q345R steel plate with excellent low-temperature impact toughness at core and manufacturing method thereof | |
| CN114959442B (en) | Steel for universal joint cross shaft for cold extrusion and manufacturing method thereof | |
| CN114134388B (en) | Thin-specification ultrahigh-strength steel plate with 1300 MPa-level tensile strength and manufacturing method thereof | |
| KR20090070501A (en) | High manganese high strength steel sheets with excellent fatigue resistance and manufacturing method thereof | |
| CN111876679B (en) | Chromium-vanadium hot-rolled steel wire rod and preparation method thereof, and preparation method of steel wire and hand tool | |
| CN114351060A (en) | Hot-rolled steel strip, preparation method thereof and application thereof in bimetal band saw backing material | |
| CN113136525A (en) | Fatigue-resistant spring steel | |
| JP2705946B2 (en) | Manufacturing method of high strength steel sheet with excellent SSC resistance | |
| CN115652208B (en) | 450MPa grade sulfuric acid dew point corrosion resistant rare earth steel and manufacturing method thereof | |
| CN114107841B (en) | High-strength corrosion-resistant spring steel and preparation method thereof | |
| CN116145017B (en) | Production method of high-toughness wear-resistant steel plate with uniform hardness in thickness direction | |
| CN115679194B (en) | Plastic mold steel plate and manufacturing method thereof | |
| CN115386791B (en) | Flat steel for micro-alloyed high-strength weldable composite stabilizer bar torsion spring and manufacturing method thereof | |
| CN110592470B (en) | Large-thickness SA302GrC steel plate with low-temperature toughness and preparation method thereof | |
| CN117344202A (en) | Spring steel and manufacturing method thereof | |
| CN113832390A (en) | Steel for non-quenched and tempered alloy structure and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| E902 | Notification of reason for refusal |