CN115386790A - 一种含铌高温渗碳齿轮钢及其生产工艺 - Google Patents
一种含铌高温渗碳齿轮钢及其生产工艺 Download PDFInfo
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- CN115386790A CN115386790A CN202210750205.6A CN202210750205A CN115386790A CN 115386790 A CN115386790 A CN 115386790A CN 202210750205 A CN202210750205 A CN 202210750205A CN 115386790 A CN115386790 A CN 115386790A
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- niobium
- gear steel
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 155
- 239000010959 steel Substances 0.000 title claims abstract description 155
- 239000010955 niobium Substances 0.000 title claims abstract description 36
- 229910052758 niobium Inorganic materials 0.000 title claims abstract description 32
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 238000010438 heat treatment Methods 0.000 claims abstract description 79
- 238000005096 rolling process Methods 0.000 claims abstract description 70
- 238000007670 refining Methods 0.000 claims abstract description 59
- 238000000034 method Methods 0.000 claims abstract description 55
- 238000009749 continuous casting Methods 0.000 claims abstract description 54
- 238000001816 cooling Methods 0.000 claims abstract description 45
- 230000008569 process Effects 0.000 claims abstract description 43
- 230000009467 reduction Effects 0.000 claims abstract description 34
- 238000003723 Smelting Methods 0.000 claims abstract description 30
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 22
- 238000009489 vacuum treatment Methods 0.000 claims abstract description 22
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 15
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 11
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 11
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 64
- 239000002893 slag Substances 0.000 claims description 48
- 238000003756 stirring Methods 0.000 claims description 36
- 229910052786 argon Inorganic materials 0.000 claims description 32
- 229910045601 alloy Inorganic materials 0.000 claims description 29
- 239000000956 alloy Substances 0.000 claims description 29
- 239000000498 cooling water Substances 0.000 claims description 27
- 238000010079 rubber tapping Methods 0.000 claims description 26
- 238000005266 casting Methods 0.000 claims description 25
- 229910052799 carbon Inorganic materials 0.000 claims description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 22
- 238000010583 slow cooling Methods 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 22
- 229910052782 aluminium Inorganic materials 0.000 claims description 20
- 238000002791 soaking Methods 0.000 claims description 20
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 19
- 238000009792 diffusion process Methods 0.000 claims description 18
- 238000007664 blowing Methods 0.000 claims description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 12
- 238000005204 segregation Methods 0.000 claims description 12
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 11
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 11
- 239000004571 lime Substances 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 8
- 229910001200 Ferrotitanium Inorganic materials 0.000 claims description 7
- 235000010627 Phaseolus vulgaris Nutrition 0.000 claims description 7
- 244000046052 Phaseolus vulgaris Species 0.000 claims description 7
- 238000004321 preservation Methods 0.000 claims description 7
- 229910000640 Fe alloy Inorganic materials 0.000 claims description 6
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 6
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 6
- 229910001309 Ferromolybdenum Inorganic materials 0.000 claims description 6
- 229910000628 Ferrovanadium Inorganic materials 0.000 claims description 6
- 229910000914 Mn alloy Inorganic materials 0.000 claims description 6
- 229910001257 Nb alloy Inorganic materials 0.000 claims description 6
- ODBHMFLQVYZPDM-UHFFFAOYSA-N [Mn].[Nb].[Fe] Chemical compound [Mn].[Nb].[Fe] ODBHMFLQVYZPDM-UHFFFAOYSA-N 0.000 claims description 6
- 238000004140 cleaning Methods 0.000 claims description 6
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 6
- PNXOJQQRXBVKEX-UHFFFAOYSA-N iron vanadium Chemical compound [V].[Fe] PNXOJQQRXBVKEX-UHFFFAOYSA-N 0.000 claims description 6
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- GFUGMBIZUXZOAF-UHFFFAOYSA-N niobium zirconium Chemical compound [Zr].[Nb] GFUGMBIZUXZOAF-UHFFFAOYSA-N 0.000 claims description 6
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- 238000009628 steelmaking Methods 0.000 claims description 6
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- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 4
- 239000010436 fluorite Substances 0.000 claims description 4
- 238000004886 process control Methods 0.000 claims description 2
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- 230000001976 improved effect Effects 0.000 abstract description 26
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- 229910000859 α-Fe Inorganic materials 0.000 description 37
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- 229910052710 silicon Inorganic materials 0.000 description 9
- 239000011575 calcium Substances 0.000 description 8
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- 230000008859 change Effects 0.000 description 8
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- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 7
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- 230000001502 supplementing effect Effects 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- 229910052726 zirconium Inorganic materials 0.000 description 5
- 239000002131 composite material Substances 0.000 description 4
- 239000011572 manganese Substances 0.000 description 4
- 230000006911 nucleation Effects 0.000 description 4
- 238000010899 nucleation Methods 0.000 description 4
- 230000001681 protective effect Effects 0.000 description 4
- 238000010008 shearing Methods 0.000 description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
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- 239000006185 dispersion Substances 0.000 description 3
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- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000010791 quenching Methods 0.000 description 3
- 230000000171 quenching effect Effects 0.000 description 3
- 238000004513 sizing Methods 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 2
- 229910001567 cementite Inorganic materials 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 230000008025 crystallization Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 229910017464 nitrogen compound Inorganic materials 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 150000003568 thioethers Chemical class 0.000 description 2
- GPPXJZIENCGNKB-UHFFFAOYSA-N vanadium Chemical compound [V]#[V] GPPXJZIENCGNKB-UHFFFAOYSA-N 0.000 description 2
- 238000007546 Brinell hardness test Methods 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 229910004349 Ti-Al Inorganic materials 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 229910004692 Ti—Al Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
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- 230000009931 harmful effect Effects 0.000 description 1
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- 238000011534 incubation Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
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- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- UNASZPQZIFZUSI-UHFFFAOYSA-N methylidyneniobium Chemical compound [Nb]#C UNASZPQZIFZUSI-UHFFFAOYSA-N 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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- 230000024121 nodulation Effects 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
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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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/58—Roll-force control; Roll-gap control
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- 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
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
-
- 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
- B22D11/18—Controlling or regulating processes or operations for pouring
-
- 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
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
-
- 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
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
- B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—Processes yielding slags of special composition
-
- 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
- C21C7/0006—Adding metallic additives
-
- 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
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
-
- 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
- C21C7/06—Deoxidising, e.g. killing
-
- 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
- C21D11/00—Process control or regulation for heat treatments
- C21D11/005—Process control or regulation for heat treatments for cooling
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/007—Heat treatment of ferrous alloys containing Co
-
- 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
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment 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
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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Abstract
本发明涉及一种含铌高温渗碳齿轮钢及其生产工艺,其组成成分按质量百分数计包括:C:0.16~0.22%、Si:0.05~0.16%、Mn:0.45~0.75%、P≤0.020%、S≤0.02%、Cr:0.3~0.6%、Ni:0.8~1.25%、Mo:0.12~0.25%、Nb:0.02~0.045%、V:0.04~0.1%、Ti:0.006~0.025%、Al≤0.035%、B≤0.006%、Cu≤0.15%、Co≤0.006%,Zr≤0.006%,N:100~200ppm、H≤2.0ppm、O≤20ppm;工艺包括依次经电炉冶炼、LF精炼、VD真空处理、连铸、加热、轧制和控冷工序得到高温渗碳齿轮钢,高温渗碳齿轮钢屈服强度为1090‑1170Mpa,抗拉强度为1380‑1495Mpa,延伸率≥20%,断面收缩率≥45%,冲击值KV2≥59/J,组织晶粒度≥9级,最大限度利用晶粒细化的强化作用,有效减小夹杂,改善低倍致密性、晶粒组织,提高钢材的强度、韧性和疲劳性能。
Description
技术领域
本发明属于齿轮钢技术领域,具体涉及一种含铌高温渗碳齿轮钢及其生产工艺。
背景技术
风电齿轮作为风电设备传动系统的关键部件,要求材料具体极高的可靠性、长寿命、抗冲击、耐磨损等性能,借助高强度化材料减小齿宽有利于提高产品轻量化。高温渗碳由于温度较高,依照断面形状轧制后的温度在950-1050℃之间,铁素体的成核位置是奥氏体相晶界面热变形和变形区引起的退火孪晶的内部界面,奥氏体晶粒易粗化,降低钢的尤其是塑性的常温力学性能,渗碳保温时间较长而导致生产效率低下,在钢中利用微合金元素形成细小的碳化物、氮化物或碳氮化合物,其质点扎钉在晶界,在加热过程中可以阻止奥氏体晶粒的长大,但容易生成铁素体δ相或其他脆性相而使韧性、淬透性降低,热加工性能变坏。低碳之钛钢的钢液粘度较大,成分波动大,非金属夹杂物和皮下多孔等缺陷也促使钢形成热加工纤维组织与带状组织,使材料具有各向异性,使钢在热加工与热处理时产生裂纹或使用时突然脆断。工艺控制不当使液相中的原子来得及扩散而固相中的原子来不及扩散,以至于固溶体先结晶中心和后结晶部分成分不同成为晶内偏析,形变能诱导部分奥氏体提前转化为铁素体造成相变的铁素体不稳定,发生回复和再结晶导致晶粒粗化,组织形态分布不均匀,难以获得高强度高韧性的综合性能,容易疲劳失效。
发明内容
本发明旨在至少在一定程度上解决上述技术问题之一,本发明提供一种含铌高温渗碳齿轮钢及其生产工艺,优化的成分设计,合适的电炉冶炼、LF精炼、VD真空处理、连铸、加热、轧制和控冷工艺,最大限度利用晶粒细化的强化作用,有效减小夹杂,改善低倍致密性、晶粒组织,提高钢材的强度、韧性和疲劳性能。
本发明解决其技术问题所采用的技术方案是:
一种含铌高温渗碳齿轮钢,其组成成分按质量百分数计为:C:0.16~0.22%、Si:0.05~0.16%、Mn:0.45~0.75%、P≤0.020%、S≤0.02%、Cr:0.3~0.6%、Ni:0.8~1.25%、Mo:0.12~0.25%、Nb:0.02~0.045%、V:0.04~0.1%、Ti:0.006~0.025%、Al≤0.035%、B≤0.006%、Cu≤0.15%、Co≤0.006%,Zr≤0.006%,N:100~200ppm、H≤2.0ppm、O≤20ppm;余量为Fe及不可避免杂质。
进一步地,所述高温渗碳齿轮钢的屈服强度为1090-1170Mpa,抗拉强度为1380-1495Mpa,延伸率≥20%,断面收缩率≥45%,冲击值KV2≥59/J。
上述含铌高温渗碳齿轮钢的成分设计原因为:
(1)C:C元素是获得所需强度水平的廉价元素,但C含量过高有降低耐大气腐蚀、增加冷脆性和时效敏感性,降低韧性和延性,故C含量设计为0.16~0.22%。
(2)Si:Si作为脱氧剂存在,与钢水中的FeO能结成密度较小的硅酸盐炉渣而被出去,增加钢的强度和硬度,但硅含量过高会减小渗碳层厚度和碳的浓度,使钢材在后续的热处理中的晶界氧化趋势劣化,降低钢的塑性和韧性,在渗层中易导致内氧化形成黑色网状组织缺陷而急剧降低疲劳寿命,因此Si含量设计为0.2~0.45%;
(3)Mn、Mo:Mn能消除或减弱由于硫引起的钢的热脆性,改善钢的热加工性能,锰和铁形成固溶体提高铁素体和奥氏体的硬度和强度,但Mn过高有促进晶粒长大的作用,会增加线胀系数,使快速加热或冷却时形成较大内应力而造成开裂倾向,易形成带状或纤维组织导致纵、横向性能差较大,因此Mn含量设计为0.45~0.75%,少量Mo利于细化相变过程中或相变后析出的微合金碳氮化合物,属于缩小γ相区的元素,与铁和碳形成复合渗碳体可以提高耐磨性、渗碳性能,但Mo过高会出现脆性相时韧性降低,因此Mo含量设计为0.12~0.25%,并加入V细化晶粒,改善力学性能。
(4)Cr:Cr是次要的固溶强化元素,可提高钢的淬透性和耐磨性、改善耐腐蚀性和抗氧化性,提高强度、硬度和屈服点,Cr与Mo结合使淬火中残余奥氏体增加和均匀分布,降低脱碳作用,但Cr过高长时间渗碳会粗晶,因此Cr含量设计为0.3~0.6%。
(5)Ni:Ni能提高钢的强度和韧性,提高淬透性,可阻止高温时晶粒的增长仍可保持细晶粒组织,强烈提高钢强度的同时使韧性保持极高水平,Ni过高易氧化起鳞,氧化铁皮粘在钢表面不易脱落,促进淬火冷却过程中沿奥氏体晶界析出碳化物,因此Ni含量设计为0.8~1.25%。
(6)V、Ti、Nb、N:复合V、Ti、Nb等固溶于钢中的微合金化元素提高过冷奥氏体的稳定性、降低转变温度,改善钢的显微组织、细化晶粒,增加晶界面积,使晶界上杂质元素偏析浓度下降,降低韧脆转折温度而提高强度的同时保证塑性和韧性;V固溶于奥氏体中可提高钢的淬透性,细化晶粒以提高冲击韧性,对渗碳有利,但V过高会阻碍钢的脱碳及石墨化作用,因此V含量设计为0.04~0.1%;Nb/Ti的复合微合金化析出可更好的细化晶粒,易增加弥散分布均匀性,渗碳保温长时间也不会出现混晶现象,Ti含量设计为:0.006~0.025%;Nb具有最强的晶粒细化强化效果,Nb(C,N)的钉扎作用使控轧控冷效果最佳,可提高奥氏体的再结晶温度、有效阻止奥氏体晶粒长大,替代V具有高温稳定性,但Nb过高会使Nb(C,N)析出时长大而不利于扎钉作用,Nb含量设计为:0.02~0.045%;增加N是强烈的A体形成元素,可使细小析出相增多,使氮固定AlN、VN中消除时效倾向,但N过高易析出粗大的TiN损害切削加工性和疲劳性能,N含量设计为100~200ppm。
(7)Al:AlN具有强化沉淀和细晶强化作用,但Al过高会恶化钢水的可浇性导致钢水出口结瘤堵塞,且AlN在低温过饱和铁素体中形核困难,因此Al含量设计为≤0.035%。
(8)B、Cu、Co、Zr:极微量B在奥氏体晶界上偏聚而抑制铁素体新相形核,提高淬透性,但B含量过大易粗晶、产生非金属夹杂物,因此B含量设计为≤0.006%;Cu能提高强度和韧性、减少应力腐蚀与介质腐蚀的有害影响,但Cu过高会在热加工时产生热脆、影响塑性,因此Cu含量设计为≤0.15%;Co增加强度和耐热性,造成均匀弥散分布的第二相粒子,使大量细小、弥散的析出相在位错处形成,能细化晶粒,增强固溶强化,降低钢的过热倾向性而提高耐用度,但Co含量过高时易出现脱碳倾向,降低奥氏体的稳定性,析出硬而脆的金属间化合物而使机械性能变坏,因此Co含量设计为≤0.006%;极微量Zr对渗碳体球化有促进作用,具有脱氧、净化和细化晶粒的作用,有利于提高韧性和冲压性能、消除时效现象,夹杂物MnS依附在Zr-Ti-Al的复合氧化物上形核并生长减小了粗大铁素体的数量,使氧化物和氮化物粒子密度更高且尺寸更细小,使长条状的共晶组织逐渐团聚,组织形态分布均匀,但Zr过高会形成粗大的Al3Zr相而使组织偏大,因此Zr含量设计为≤0.006%。
(8)P、S:磷易使晶格歪曲、晶粒长大,引起塑性、冲击韧性显著降低,硫易降低钢的延展性和韧性,在轧制时造成裂纹,磷和硫含量越低越好,因此P含量设计为≤0.020%,S含量设计为≤0.02%。
上述一种含铌高温渗碳齿轮钢的生产工艺,其工艺包括以下步骤:
S1、电炉冶炼:炼钢原料经电炉冶炼得到钢水,控制电炉出钢终点C:0.06~0.11%,防止钢水过氧化,有利于夹杂物的去除;控制电炉出钢目标P≤0.007%,目标温度T≥1600℃,控制合适的出钢温度,有效控制钢水回P;出钢过程进行滑板挡渣操作,减少下渣;
每炉钢水90-110t,出钢过程中依次加入90-110kg铝饼、450-510kg硅锰合金(FeMn64Si18)、130-170kg低碳锰铁(FeMn84C0.4)、300-350kg促净剂(CaO53.5%,SiO23.5%,Al2O334.3%,MgO8.5%)、200-260kg石灰进行脱氧和造渣预精炼,减少氧化物夹杂提高疲劳寿命;
S2、LF精炼:将经步骤S1的钢水随钢水包经吊装设备吊至LF炉工位,对钢水包内部的钢水进行精炼,采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧减少合金增硅并使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期少量多批次加入扩散脱氧剂以保持还原性气氛,精炼渣终渣碱度为3~6;
LF精炼过程保持氩气通畅,LF精炼前期补加0~100kg石灰或萤石进行调渣,氩气流量为240~280NL/min,促进脱氧及合金化;
LF精炼中期加微碳铬铁(FeCr69C0.03)、铌锰铁合金(FeMn30Nb17)、钒铁合金(FeV50-B)、钼铁合金(FeMo60-C)均保持氩气中等氩气强度,氩气流量为160~250NL/min,与钢中的碳生成稳定的碳化铌,均匀地分布在钢的晶粒边界,防止高温下钢的晶粒长大,对钢的组织起细化作用,可提高钢的强度、韧性和蠕变性能;
LF精炼后期氩气流量为50~100NL/min,弱搅拌镇静,防止钢水翻滚厉害产生卷渣,通过此工艺合金成分得到精准控制,缩小化学成分的波动,出站前加入6-18kg/炉硅钙线(含Si55-65%)对钢液进行钙处理,通过钙处理使硬质氧化铝夹杂变形为软质夹杂,生成低熔点且容易上浮的钙铝酸盐复合夹杂,进一步脱氧脱硫,避免生成枝晶状MnS而引起塑性和韧性下降,LF出站前S含量≤0.002%,温度≥1615℃;
S3、VD真空处理:将经步骤S2的钢水进VD站真空处理,控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,去除钢水中的H,确保夹杂物充分上浮,真空处理结束后加入低碳硼铁合金(FeB18C0.1)、钴粉和锆铌合金(ZrNb30)进行微合金化处理,减少微合金化过程的元素烧损,使合金成分控制精准,通过B在奥氏体晶界上偏聚而抑制铁素体新相形核提高淬透性,通过Co和Zr造成均匀弥散分布的第二相粒子,使大量细小、弥散的析出相在位错处形成、增强固溶强化,粒子通过钉扎作用细化晶粒,Zr对硫化物变质处理,ZrC、ZrN、固定C、N,提高先共析铁素体的转变温度,使粗大的硅酸盐夹杂变为细小的氧化物夹杂而细化晶粒,使铁素体相变易于发生,可延缓珠光体相变、扩大铁素体转变的孕育期和生长期而消除钢种的各向异性,以便析出细小的ZrN和NbC而提高韧性;
软吹过程中底吹氮气流量为10~20NL/min,防止钢水的二次氧化,破空后喂入2-3m/t铝线和1-2m/t钛铁包芯线,以调整钢水中[Al]和[Ti]的含量,减少元素二次氧化,采用微钛处理改善热影响区的韧性,控制A、B、C、D类夹杂在1.5级以内,DS类夹杂≤1.0级,提高了钢水的纯净度;
S4、连铸:将经步骤S3的钢水通过连铸机全程保护浇铸防止二次氧化,控制低过热度浇注,过热度在10-25℃之间,有效降低铸坯的偏析,提高铸坯低倍致密性;
采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为3600-3800L/min,一冷水快冷增加柱状晶比例使钢坯致密性更好,二冷水一区水流量为22-30L/min,二冷水二区水流量为48-52L/min,适当提高二冷强度细化晶粒,缩短液相深度;
结晶器电磁搅拌(M-EMS)电流260-280A、频率为2Hz,铸流搅拌(S-EMS)电流为400-420A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1080-1100A、频率为8Hz,有效控制枝晶产生,避免由枝晶偏析和非金属夹杂延伸而形成带状组织,有利于中心缩孔及中心裂纹处补充钢水,减少液面波动,防止表面卷渣,控制拉速为0.24-0.29m/min,定尺切割得到得到连铸坯,采用合适的拉速和冷却制度保证连铸坯表面质量,控制连铸坯的中心疏松、一般疏松、中心偏析在1.5级以内,连铸坯>550℃入缓冷坑保温24h以上,防止铸坯开裂,对缓冷后的连铸坯抛丸处理,提高连铸坯的表面质量;
S5、加热:将步骤S4的连铸圆坯送至加热炉加热,加热炉的加热程序为:预热段温度预热段温度<850℃,预热段目标825℃,钢坯预热减小钢坯开裂的风险,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h,通过两段加热及一段均热,使连铸圆坯内外温度均匀、微合金元素充分固溶,而又符合轧制要求的最佳温度,充分发挥铌、钒、钴和锆微合金元素细化晶粒和沉淀强化作用,减小硫化物平均尺寸,提高强度;
S6、轧制:将步骤S5的连铸坯经水压为18-20MP的高压水除磷和开坯机后轧制成中间坯,经液压剪切头尾,由粗轧-中轧-精轧机组14道次连轧得到轧坯,开轧温度900-1010℃,在奥氏体单相区进行轧制控制,出连轧温度790-830℃,前期轧制压下量≤65mm/道次,单道次低温大压下量,可有效焊合铸坯内部缺陷消除,可获得内部质密性良好,中期轧制不少于三个道次压下量≥100mm/道次,在奥氏体动态再结晶以下的奥氏体未再结晶区增大变形带,使变形带上形成的铁素体晶粒细小,后期成品及成品前道次压下量控制在8~20mm,轻下压控制轧制精度,通过控制压下量、开轧温度和出连轧温度,通过降低坯料的再加热温度,在奥氏体相变到铁氧体的再结晶过程中的铁素体稳定,变形带中诱导相变的铁素体形核点较多、晶粒细化、提高钢材的强度和韧性,改善了内部致密性;
S7、控冷:将经步骤S6的轧坯入冷床以≥15℃/s的速度风冷,控制变形奥氏体的组织形态、阻止晶粒长大或碳化物过早析出而形成网状组织,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,控制钢材相变冷却温度以保证获得要求的相变组织和性能,缓冷至温度≤250℃出坑,得到高温渗碳齿轮钢,控轧控冷轧制后铁素能够在晶粒内部和晶界成核,铁素体变形量小,晶粒内错位密度增高产生拉长后细小的亚晶,在奥氏体的基础上形成高密度铁素体使变相后均匀的微观结构细化,形成铁素体+珠光体,晶粒度≥9级,带状组织≤2级,碳化物网状≤1.5级,有效改善晶粒组织,提高钢材的强度、韧性和疲劳性能,高温渗碳齿轮钢依次经取样、精整、探伤后入库。
与现有技术相比,本发明的有益效果是:
(1)采用优化的成分设计,低Si改善黑色网状组织缺陷,少量Mo细化相变过程中或相变后析出的微合金碳氮化合物,复合V、Ti、Nb细化晶粒,增加弥散分布均匀性,B、Cu、Co、Zr造成均匀弥散分布的第二相粒子,使氧化物和氮化物粒子密度更高且尺寸更细小,组织形态分布均匀。
(2)采用纯净钢冶炼工艺,电炉冶炼脱氧和造渣预精炼减少氧化物夹杂,LF精炼扩散脱氧减少合金增硅,促进脱氧及合金化,VD真空处理采用微钛处理改善热影响区的韧性,最大限度利用晶粒细化的强化作用,控制A、B、C、D类夹杂在1.5级以内,DS类夹杂≤1.0级,提高了钢水的纯净度,扩大铁素体转变的孕育期和生长期而消除钢种的各向异性。
(3)采用低过热度浇注,合适的拉速和冷却制度,控制连铸坯的中心疏松、一般疏松、中心偏析在1.5级以内,提高铸坯低倍致密性。
(4)通过加热制度充分发挥微合金元素细化晶粒和沉淀强化作用,通过控制压下量、开轧温度和出连轧温度在奥氏体相变到铁氧体的再结晶过程中的铁素体稳定,控轧控冷轧制后铁素能够在晶粒内部和晶界成核,有效改善晶粒组织,提高钢材的强度、韧性和疲劳性能。
具体实施方式
下面详细描述本发明的实施例是示例性的,旨在用于解释本发明,而不能理解为对本发明的限制。
实施例1:
本发明所述一种含铌高温渗碳齿轮钢的一种较佳实施方式,其组成成分按质量百分数计为:C:0.18%、Si:0.11%、Mn:0.62%、P:0.01%、S:0.01%、Cr:0.35%、Ni:0.94%、Mo:0.22%、Nb:0.04%、V:0.045%、Ti:0.01%、Al:0.02%、B:0.004%、Cu:0.12%、Co:0.001%,Zr:0.003%,N:158ppm、H:1.5ppm、O:13ppm;余量为Fe及不可避免杂质。
上述一种含铌高温渗碳齿轮钢的生产工艺,其工艺包括以下步骤:
S1、电炉冶炼:炼钢原料经电炉冶炼得到钢水,控制电炉出钢终点C:0.08%,电炉出钢目标P≤0.007%,目标温度T≥1600℃,出钢过程进行滑板挡渣操作,减少下渣;
每炉钢水95t,出钢过程中依次加入98kg铝饼、478kg硅锰合金(FeMn64Si18)、135kg低碳锰铁(FeMn84C0.4)、312kg促净剂(CaO53.5%,SiO23.5%,Al2O334.3%,MgO8.5%)、245kg石灰进行脱氧和造渣预精炼;
S2、LF精炼:将经步骤S1的钢水随钢水包经吊装设备吊至LF炉工位,对钢水包内部的钢水进行精炼,采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧减少合金增硅并使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期少量多批次加入扩散脱氧剂以保持还原性气氛,精炼渣终渣碱度为3~6;
LF精炼过程保持氩气通畅,LF精炼前期补加15kg萤石进行调渣,氩气流量为260NL/min,促进脱氧及合金化;
LF精炼中期加微碳铬铁(FeCr69C0.03)、铌锰铁合金(FeMn30Nb17)、钒铁合金(FeV50-B)、钼铁合金(FeMo60-C)均保持氩气中等氩气强度,氩气流量为180NL/min;
LF精炼后期氩气流量为75NL/min,出站前加入12kg/炉硅钙线(含Si55-65%)对钢液进行钙处理,LF出站前S含量≤0.002%,温度≥1615℃;
S3、VD真空处理:将经步骤S2的钢水进VD站真空处理,控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,真空处理结束后加入低碳硼铁合金(FeB18C0.1)、钴粉和锆铌合金(ZrNb30)进行微合金化处理;软吹过程中底吹氮气流量为10~20NL/min,破空后喂入2.5m/t铝线和1.5m/t钛铁包芯线;
S4、连铸:将经步骤S3的钢水通过连铸机全程保护浇铸,过热度在10-25℃之间;
采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为3700L/min,一冷水快冷增加柱状晶比例使钢坯致密性更好,二冷水一区水流量为24L/min,二冷水二区水流量为50L/min;
结晶器电磁搅拌(M-EMS)电流270A、频率为2Hz,铸流搅拌(S-EMS)电流为410A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1090A、频率为8Hz,控制拉速为0.26m/min,定尺切割得到得到连铸坯,连铸坯>550℃入缓冷坑保温24h以上,对缓冷后的连铸坯抛丸处理;
S5、加热:将步骤S4的连铸圆坯送至加热炉加热,加热炉的加热程序为:预热段温度预热段温度<850℃,预热段目标825℃,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h;
S6、轧制:将步骤S5的连铸坯经水压为19MP的高压水除磷和开坯机后轧制成中间坯,经液压剪切头尾,由粗轧-中轧-精轧机组14道次连轧得到轧坯,开轧温度980℃,出连轧温度825℃,前期轧制压下量≤65mm/道次,中期轧制不少于三个道次压下量≥100mm/道次,后期成品及成品前道次压下量控制在8~20mm;
S7、控冷:将经步骤S6的轧坯入冷床以≥15℃/s的速度风冷,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,缓冷至温度≤250℃出坑,得到高温渗碳齿轮钢,形成铁素体+珠光体,高温渗碳齿轮钢依次经取样、精整、探伤后入库。
实施例2:
本发明所述一种含铌高温渗碳齿轮钢的一种较佳实施方式,其组成成分按质量百分数计为:C:0.17%、Si:0.08%、Mn:0.5%、P:0.01%、S:0.015%、Cr:0.45%、Ni:1.1%、Mo:0.2%、Nb:0.03%、V:0.07%、Ti:0.012%、Al:0.02%、B:0.004%、Cu:0.13%、Co:0.004%,Zr:0.004%,N:154ppm、H:1.4ppm、O:15ppm;余量为Fe及不可避免杂质。
上述一种含铌高温渗碳齿轮钢的生产工艺,其工艺包括以下步骤:
S1、电炉冶炼:炼钢原料经电炉冶炼得到钢水,控制电炉出钢终点C:0.1%,电炉出钢目标P≤0.007%,目标温度T≥1600℃,出钢过程进行滑板挡渣操作,减少下渣;
每炉钢水102t,出钢过程中依次加入94kg铝饼、478kg硅锰合金(FeMn64Si18)、165kg低碳锰铁(FeMn84C0.4)、322kg促净剂(CaO53.5%,SiO23.5%,Al2O334.3%,MgO8.5%)、214kg石灰进行脱氧和造渣预精炼;
S2、LF精炼:将经步骤S1的钢水随钢水包经吊装设备吊至LF炉工位,对钢水包内部的钢水进行精炼,采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧减少合金增硅并使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期少量多批次加入扩散脱氧剂以保持还原性气氛,精炼渣终渣碱度为3~6;
LF精炼过程保持氩气通畅,LF精炼前期补加12kg石灰进行调渣,氩气流量为245NL/min,促进脱氧及合金化;
LF精炼中期加微碳铬铁(FeCr69C0.03)、铌锰铁合金(FeMn30Nb17)、钒铁合金(FeV50-B)、钼铁合金(FeMo60-C)均保持氩气中等氩气强度,氩气流量为170NL/min;
LF精炼后期氩气流量为90NL/min,出站前加入10kg/炉硅钙线(含Si55-65%)对钢液进行钙处理,LF出站前S含量≤0.002%,温度≥1615℃;
S3、VD真空处理:将经步骤S2的钢水进VD站真空处理,控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,真空处理结束后加入低碳硼铁合金(FeB18C0.1)、钴粉和锆铌合金(ZrNb30)进行微合金化处理;软吹过程中底吹氮气流量为14NL/min,破空后喂入2.6m/t铝线和1.3m/t钛铁包芯线;
S4、连铸:将经步骤S3的钢水通过连铸机全程保护浇铸,过热度在10-25℃之间;
采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为2750L/min,一冷水快冷增加柱状晶比例使钢坯致密性更好,二冷水一区水流量为26L/min,二冷水二区水流量为49L/min;
结晶器电磁搅拌(M-EMS)电流260A、频率为2Hz,铸流搅拌(S-EMS)电流为400A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1080A、频率为8Hz,控制拉速为0.29m/min,定尺切割得到得到连铸坯,连铸坯>550℃入缓冷坑保温24h以上,对缓冷后的连铸坯抛丸处理;
S5、加热:将步骤S4的连铸圆坯送至加热炉加热,加热炉的加热程序为:预热段温度预热段温度<850℃,预热段目标825℃,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h;
S6、轧制:将步骤S5的连铸坯经水压为18MP的高压水除磷和开坯机后轧制成中间坯,经液压剪切头尾,由粗轧-中轧-精轧机组14道次连轧得到轧坯,开轧温度960℃,出连轧温度810℃,前期轧制压下量≤65mm/道次,中期轧制不少于三个道次压下量≥100mm/道次,后期成品及成品前道次压下量控制在8~20mm;
S7、控冷:将经步骤S6的轧坯入冷床以≥15℃/s的速度风冷,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,缓冷至温度≤250℃出坑,得到高温渗碳齿轮钢,形成铁素体+珠光体,高温渗碳齿轮钢依次经取样、精整、探伤后入库。
实施例3:
本发明所述一种含铌高温渗碳齿轮钢的一种较佳实施方式,其组成成分按质量百分数计为:C:0.21%、Si:0.12%、Mn:0.71%、P:0.01%、S:0.01%、Cr:0.48%、Ni:0.9%、Mo:0.2%、Nb:0.33%、V:0.07%、Ti:0.011%、Al:0.03%、B:0.004%、Cu:0.05%、Co:0.004%,Zr:0.003%,N:140ppm、H:1.7ppm、O:12ppm;余量为Fe及不可避免杂质。
上述一种含铌高温渗碳齿轮钢的生产工艺,其工艺包括以下步骤:
S1、电炉冶炼:炼钢原料经电炉冶炼得到钢水,控制电炉出钢终点C:0.08%,电炉出钢目标P≤0.007%,目标温度T≥1600℃,出钢过程进行滑板挡渣操作,减少下渣;
每炉钢水106t,出钢过程中依次加入100kg铝饼、480kg硅锰合金(FeMn64Si18)、140kg低碳锰铁(FeMn84C0.4)、320kg促净剂(CaO53.5%,SiO23.5%,Al2O334.3%,MgO8.5%)、220kg石灰进行脱氧和造渣预精炼;
S2、LF精炼:将经步骤S1的钢水随钢水包经吊装设备吊至LF炉工位,对钢水包内部的钢水进行精炼,采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧减少合金增硅并使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期少量多批次加入扩散脱氧剂以保持还原性气氛,精炼渣终渣碱度为3~6;
LF精炼过程保持氩气通畅,LF精炼前期补加25kg石灰进行调渣,氩气流量为250NL/min,促进脱氧及合金化;
LF精炼中期加微碳铬铁(FeCr69C0.03)、铌锰铁合金(FeMn30Nb17)、钒铁合金(FeV50-B)、钼铁合金(FeMo60-C)均保持氩气中等氩气强度,氩气流量为220NL/min;
LF精炼后期氩气流量为80NL/min,出站前加入15kg/炉硅钙线(含Si55-65%)对钢液进行钙处理,LF出站前S含量≤0.002%,温度≥1615℃;
S3、VD真空处理:将经步骤S2的钢水进VD站真空处理,控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,真空处理结束后加入低碳硼铁合金(FeB18C0.1)、钴粉和锆铌合金(ZrNb30)进行微合金化处理;软吹过程中底吹氮气流量为12NL/min,破空后喂入2.8m/t铝线和1.5m/t钛铁包芯线;
S4、连铸:将经步骤S3的钢水通过连铸机全程保护浇铸,过热度在10-25℃之间;
采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为3600L/min,一冷水快冷增加柱状晶比例使钢坯致密性更好,二冷水一区水流量为27L/min,二冷水二区水流量为50L/min;
结晶器电磁搅拌(M-EMS)电流280A、频率为2Hz,铸流搅拌(S-EMS)电流为420A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1100A、频率为8Hz,控制拉速为0.28m/min,定尺切割得到得到连铸坯,连铸坯>550℃入缓冷坑保温24h以上,对缓冷后的连铸坯抛丸处理;
S5、加热:将步骤S4的连铸圆坯送至加热炉加热,加热炉的加热程序为:预热段温度预热段温度<850℃,预热段目标825℃,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h;
S6、轧制:将步骤S5的连铸坯经水压为19MP的高压水除磷和开坯机后轧制成中间坯,经液压剪切头尾,由粗轧-中轧-精轧机组14道次连轧得到轧坯,开轧温度995℃,出连轧温度812℃,前期轧制压下量≤65mm/道次,中期轧制不少于三个道次压下量≥100mm/道次,后期成品及成品前道次压下量控制在8~20mm;
S7、控冷:将经步骤S6的轧坯入冷床以≥15℃/s的速度风冷,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,缓冷至温度≤250℃出坑,得到高温渗碳齿轮钢,形成铁素体+珠光体,高温渗碳齿轮钢依次经取样、精整、探伤后入库。
实施例4:
本发明所述一种含铌高温渗碳齿轮钢的一种较佳实施方式,其组成成分按质量百分数计为:C:0.22%、Si:0.14%、Mn:0.48%、P:0.01%、S:0.01%、Cr:0.45%、Ni:0.96%、Mo:0.23%、Nb:0.025%、V:0.055%、Ti:0.022%、Al:0.017%、B:0.04%、Cu:0.08%、Co:0.005%,Zr:0.004%,N:125ppm、H:1.4ppm、O:17ppm;余量为Fe及不可避免杂质。
上述一种含铌高温渗碳齿轮钢的生产工艺,其工艺包括以下步骤:
S1、电炉冶炼:炼钢原料经电炉冶炼得到钢水,控制电炉出钢终点C:0.09%,电炉出钢目标P≤0.007%,目标温度T≥1600℃,出钢过程进行滑板挡渣操作,减少下渣;
每炉钢水97t,出钢过程中依次加入108kg铝饼、477kg硅锰合金(FeMn64Si18)、164kg低碳锰铁(FeMn84C0.4)、312kg促净剂(CaO53.5%,SiO23.5%,Al2O334.3%,MgO8.5%)、210kg石灰进行脱氧和造渣预精炼;
S2、LF精炼:将经步骤S1的钢水随钢水包经吊装设备吊至LF炉工位,对钢水包内部的钢水进行精炼,采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧减少合金增硅并使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期少量多批次加入扩散脱氧剂以保持还原性气氛,精炼渣终渣碱度为3~6;
LF精炼过程保持氩气通畅,LF精炼前期补加10kg萤石进行调渣,氩气流量为275NL/min,促进脱氧及合金化;
LF精炼中期加微碳铬铁(FeCr69C0.03)、铌锰铁合金(FeMn30Nb17)、钒铁合金(FeV50-B)、钼铁合金(FeMo60-C)均保持氩气中等氩气强度,氩气流量为170NL/min;
LF精炼后期氩气流量为60NL/min,出站前加入9kg/炉硅钙线(含Si55-65%)对钢液进行钙处理,LF出站前S含量≤0.002%,温度≥1615℃;
S3、VD真空处理:将经步骤S2的钢水进VD站真空处理,控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,真空处理结束后加入低碳硼铁合金(FeB18C0.1)、钴粉和锆铌合金(ZrNb30)进行微合金化处理;软吹过程中底吹氮气流量为14NL/min,破空后喂入2.2m/t铝线和1.7m/t钛铁包芯线;
S4、连铸:将经步骤S3的钢水通过连铸机全程保护浇铸,过热度在10-25℃之间;
采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为3800L/min,一冷水快冷增加柱状晶比例使钢坯致密性更好,二冷水一区水流量为24L/min,二冷水二区水流量为49L/min;
结晶器电磁搅拌(M-EMS)电流280A、频率为2Hz,铸流搅拌(S-EMS)电流为410A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1090A、频率为8Hz,控制拉速为0.27m/min,定尺切割得到得到连铸坯,连铸坯>550℃入缓冷坑保温24h以上,对缓冷后的连铸坯抛丸处理;
S5、加热:将步骤S4的连铸圆坯送至加热炉加热,加热炉的加热程序为:预热段温度预热段温度<850℃,预热段目标825℃,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h;
S6、轧制:将步骤S5的连铸坯经水压为20MP的高压水除磷和开坯机后轧制成中间坯,经液压剪切头尾,由粗轧-中轧-精轧机组14道次连轧得到轧坯,开轧温度925℃,出连轧温度799℃,前期轧制压下量≤65mm/道次,中期轧制不少于三个道次压下量≥100mm/道次,后期成品及成品前道次压下量控制在8~20mm;
S7、控冷:将经步骤S6的轧坯入冷床以≥15℃/s的速度风冷,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,缓冷至温度≤250℃出坑,得到高温渗碳齿轮钢,形成铁素体+珠光体,高温渗碳齿轮钢依次经取样、精整、探伤后入库。
对比例:一种齿轮钢,其组成成分按质量百分数计为:C:0.23%、Si:0.36%、Mn:0.8%、P:0.02%、S:0.025%、Cr:0.68%、Ni:0.64%、Mo:0.28%、Ti:0.01%、Al:0.02%、V:0.05%、Cu:0.15%、N:125ppm、H:1.4ppm、O:17ppm;余量为Fe及不可避免杂质。
将实施例1-4和对比例的钢按照GB228标准进行金属拉伸试验,按照GB229标准进行金属夏比(U型缺口)冲击试验,按照GB231标准进行金属布氏硬度试验,其结果如下表1所示:
由上表可知,本发明高温渗碳齿轮钢的屈服强度为1090-1170Mpa,抗拉强度为1380-1495Mpa,延伸率≥20%,断面收缩率≥45%,冲击值KV2≥59/J,在奥氏体的基础上形成高密度铁素体使变相后均匀的微观结构细化,形成铁素体+珠光体,晶粒度≥9级,带状组织≤2级,碳化物网状≤1.5级,有效改善晶粒组织,提高钢材的强度、韧性和疲劳性能。
将实施例1-4和对比例的钢按照GB/T10561标准进行钢中非金属夹杂物含量的测定与标准评级图显微检测,其结果如下表2:
由上表可知,本发明可稳定地控制A、B、C、D类夹杂在1.5级以内,DS类夹杂≤1.0级,避免非金属夹杂物降低钢的机械性能,特别是降低塑性、韧性及疲劳极限,避免钢在热加工与热处理时产生裂纹或使用时突然脆断。
将实施例1-4和对比例的钢按照GB226标准进行钢的低倍组织及缺陷酸腐蚀试验,其结果如下表3:
序号 | 中心疏松/级 | 一般疏松/级 | 中心偏析/级 |
实施例1 | 0.5 | 0.5 | 1.0 |
实施例2 | 1.0 | 1.0 | 0.5 |
实施例3 | 0.5 | 0.5 | 0.5 |
实施例4 | 0.5 | 0.5 | 1.0 |
对比例1 | 1.5 | 2.0 | 2.5 |
由上表可知,本发明采用合适的拉速和冷却制度保证连铸坯表面质量,中心疏松、一般疏松、中心偏析在1.5级以内,避免加工过程中发生断裂和强度、韧性等指标波动范围大,利于提高了钢的内部致密性和力学性能。
本发明采用优化的成分设计,采用低C含量设计提高韧性和延性,低Si改善黑色网状组织缺陷,Mn提高铁素体和奥氏体的硬度和强度的同时避免增加线胀系数,少量Mo细化相变过程中或相变后析出的微合金碳氮化合物,Cr与Mo结合使淬火中残余奥氏体增加和均匀分布,Ni提高钢的强度和韧性,复合V、Ti、Nb细化晶粒,增加弥散分布均匀性,Al强化沉淀和细晶强化,B、Cu、Co、Zr造成均匀弥散分布的第二相粒子,使大量细小、弥散的析出相在位错处形成,减小了粗大铁素体的数量,使氧化物和氮化物粒子密度更高且尺寸更细小,组织形态分布均匀。
本发明采用纯净钢冶炼工艺,电炉冶炼通过控制电炉出钢终点、目标P、目标温度和出钢脱氧和造渣预精炼减少氧化物夹杂,LF精炼采用铝豆、碳粉扩散脱氧减少合金增硅,LF精炼过程促进脱氧及合金化,合金成分得到精准控制,缩小化学成分的波动,钙处理使硬质氧化铝夹杂变形为软质夹杂,VD真空处理确保夹杂物充分上浮,微合金化处理减少微合金化过程的元素烧损,最大限度利用晶粒细化的强化作用,采用微钛处理改善热影响区的韧性,控制A、B、C、D类夹杂在1.5级以内,DS类夹杂≤1.0级,提高了钢水的纯净度,扩大铁素体转变的孕育期和生长期而消除钢种的各向异性。
本发明采用低过热度浇注,采用合适的拉速和冷却制度,有效控制枝晶产生,避免由枝晶偏析和非金属夹杂延伸而形成带状组织,有效降低铸坯的偏析,控制连铸坯的中心疏松、一般疏松、中心偏析在1.5级以内,提高铸坯低倍致密性。
本发明采用通过两段加热及一段均热充分发挥铌、钒、钴和锆微合金元素细化晶粒和沉淀强化作用,减小硫化物平均尺寸,通过控制压下量、开轧温度和出连轧温度在奥氏体相变到铁氧体的再结晶过程中的铁素体稳定,变形带中诱导相变的铁素体形核点较多、晶粒细化、提高钢材的强度和韧性,改善了内部致密性,控轧控冷轧制后铁素能够在晶粒内部和晶界成核,在奥氏体的基础上形成高密度铁素体使变相后均匀的微观结构细化,有效改善晶粒组织,提高钢材的强度、韧性和疲劳性能。
上文所列出的一系列的详细说明仅仅是针对本发明的可行性实施例的具体说明,它们并非用以限制本发明的保护范围,凡未脱离本发明技艺精神所作的等效实施例或变更均应包含在本发明的保护范围之内。
Claims (10)
1.一种含铌高温渗碳齿轮钢,其特征在于,其组成成分按质量百分数计为:C:0.16~0.22%、Si:0.05~0.16%、Mn:0.45~0.75%、P≤0.020%、S≤0.02%、Cr:0.3~0.6%、Ni:0.8~1.25%、Mo:0.12~0.25%、Nb:0.02~0.045%、V:0.04~0.1%、Ti:0.006~0.025%、Al≤0.035%、B≤0.006%、Cu≤0.15%、Co≤0.006%,Zr≤0.006%,N:100~200ppm、H≤2.0ppm、O≤20ppm;余量为Fe及不可避免杂质。
2.根据权利要求1所述的一种含铌高温渗碳齿轮钢,其特征在于,所述高温渗碳齿轮钢的屈服强度为1090-1170Mpa,抗拉强度为1380-1495Mpa,延伸率≥20%,断面收缩率≥45%,冲击值KV2≥59/J。
3.根据权利要求1或2所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,工艺包括将炼钢原料依次经电炉冶炼、LF精炼、VD真空处理、连铸工序得到连铸坯,连铸坯经加热、轧制和控冷工序得到高温渗碳齿轮钢,所述轧制工序中开轧温度900-1010℃,出连轧温度790-830℃,前期轧制压下量≤65mm/道次,中期轧制不少于三个道次压下量≥100mm/道次,后期成品及成品前道次压下量控制在8~20mm,所述控冷工序以≥15℃/s的速度风冷,在冷床温度>400℃入坑缓冷,缓冷时间≥15h,缓冷至温度≤250℃出坑,高温渗碳齿轮钢的组织晶粒度≥9级,带状组织≤2级,碳化物网状≤1.5级。
4.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述电炉冶炼工序控制电炉出钢终点C:0.06~0.11%,炉出钢目标P≤0.007%,目标温度T≥1600℃,每炉钢水90-110t,出钢过程中依次加入90-110kg铝饼、450-510kg硅锰合金、130-170kg低碳锰铁、300-350kg促净剂和200-260kg石灰进行脱氧和造渣预精炼。
5.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述LF精炼工序采用铝豆、碳粉按质量比4:1组成的扩散脱氧剂扩散脱氧使炉渣变白,白渣时间≥22min,冶炼时间≥43min,冶炼中后期保持还原性气氛,精炼渣终渣碱度为3~6。
6.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述LF精炼过程保持氩气通畅;LF精炼前期补加0~100kg石灰或萤石进行调渣,氩气流量为240~280NL/min;LF精炼中期加微碳铬铁、铌锰铁合金、钒铁合金和钼铁合金,氩气流量为160~250NL/min;LF精炼后期氩气流量为50~100NL/min;出站前加入6-18kg/炉硅钙线,LF出站前S含量≤0.002%,温度≥1615℃。
7.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述VD真空处理控制最高真空度≤67pa,真空保持时间≥12min,氮气软吹时间≥22min,真空处理结束后加入低碳硼铁合金、钴粉和锆铌合金,破空后喂入2-3m/t铝线和1-2m/t钛铁包芯线,控制A、B、C、D类夹杂在1.5级以内,DS类夹杂≤1.0级。
8.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述连铸工序控制过热度在10-25℃之间,采用两段水冷却配合结晶器电磁搅拌、铸流搅拌和末端电磁搅拌,一冷水流量为3600-3800L/min,二冷水一区水流量为22-30L/min,二冷水二区水流量为48-52L/min,结晶器电磁搅拌(M-EMS)电流260-280A、频率为2Hz,铸流搅拌(S-EMS)电流为400-420A、频率为8Hz,末端电磁搅拌(F-EMS)电流为1080-1100A、频率为8Hz,拉速为0.24-0.29m/min,控制连铸坯的中心疏松、一般疏松、中心偏析在1.5级以内,连铸坯>550℃入缓冷坑保温24h以上。
9.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述加热工序预热段温度预热段温度<850℃,预热段目标825℃,加热I段时间>1.5h、加热I段温度910-1000℃,加热I段目标温度945℃,加热II段时间≥1.0h、加热II段温度1130-1200℃,加热II段目标温度1170℃,均热段时间≥1.5h、均热段温度1180-1220℃,均热段目标温度1200℃,总加热时间≥5.5h。
10.根据权利要求3所述的一种含铌高温渗碳齿轮钢的生产工艺,其特征在于,所述轧制工序连铸坯经水压为18-20MP的高压水除磷。
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