CN117107152A - Microalloy nickel-saving austenitic stainless steel and manufacturing method thereof - Google Patents
Microalloy nickel-saving austenitic stainless steel and manufacturing method thereof Download PDFInfo
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- CN117107152A CN117107152A CN202310898691.0A CN202310898691A CN117107152A CN 117107152 A CN117107152 A CN 117107152A CN 202310898691 A CN202310898691 A CN 202310898691A CN 117107152 A CN117107152 A CN 117107152A
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- 229910000963 austenitic stainless steel Inorganic materials 0.000 title claims abstract description 156
- 238000004519 manufacturing process Methods 0.000 title abstract description 9
- 239000000126 substance Substances 0.000 claims abstract description 29
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 28
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 28
- 239000002994 raw material Substances 0.000 claims abstract description 26
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 24
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 24
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 21
- 239000012535 impurity Substances 0.000 claims abstract description 17
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 94
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 89
- 229910052759 nickel Inorganic materials 0.000 claims description 53
- 229910052799 carbon Inorganic materials 0.000 claims description 40
- 229910052742 iron Inorganic materials 0.000 claims description 39
- 239000000243 solution Substances 0.000 claims description 32
- 238000003723 Smelting Methods 0.000 claims description 25
- 229910001220 stainless steel Inorganic materials 0.000 claims description 25
- 238000007670 refining Methods 0.000 claims description 24
- 238000011282 treatment Methods 0.000 claims description 24
- 229910052804 chromium Inorganic materials 0.000 claims description 21
- 238000000034 method Methods 0.000 claims description 19
- 239000010935 stainless steel Substances 0.000 claims description 19
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 18
- 238000009749 continuous casting Methods 0.000 claims description 17
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- 239000002131 composite material Substances 0.000 claims description 15
- 238000001816 cooling Methods 0.000 claims description 14
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- 239000000956 alloy Substances 0.000 claims description 13
- 238000005266 casting Methods 0.000 claims description 13
- 238000010079 rubber tapping Methods 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000006104 solid solution Substances 0.000 claims description 7
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
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- 238000005260 corrosion Methods 0.000 abstract description 78
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 18
- 238000007254 oxidation reaction Methods 0.000 abstract description 6
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- 239000011572 manganese Substances 0.000 description 20
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 18
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- 238000012360 testing method Methods 0.000 description 16
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- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 12
- 230000010287 polarization Effects 0.000 description 12
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- 229910052710 silicon Inorganic materials 0.000 description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 9
- 238000005098 hot rolling Methods 0.000 description 9
- 239000011504 laterite Substances 0.000 description 8
- 229910001710 laterite Inorganic materials 0.000 description 8
- 238000002161 passivation Methods 0.000 description 8
- 238000005275 alloying Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 6
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 230000002829 reductive effect Effects 0.000 description 6
- 239000011593 sulfur Substances 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 5
- 230000001627 detrimental effect Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 239000013535 sea water Substances 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 4
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 229910000734 martensite Inorganic materials 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 229910052750 molybdenum Inorganic materials 0.000 description 4
- 239000011733 molybdenum Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- 238000005482 strain hardening Methods 0.000 description 4
- 229910000859 α-Fe Inorganic materials 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000010436 fluorite Substances 0.000 description 3
- 239000004615 ingredient Substances 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 229910017604 nitric acid Inorganic materials 0.000 description 3
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- 230000008569 process Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- XTQHKBHJIVJGKJ-UHFFFAOYSA-N sulfur monoxide Chemical compound S=O XTQHKBHJIVJGKJ-UHFFFAOYSA-N 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000000157 electrochemical-induced impedance spectroscopy Methods 0.000 description 2
- 229910001026 inconel Inorganic materials 0.000 description 2
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- 239000003973 paint Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- NGNBDVOYPDDBFK-UHFFFAOYSA-N 2-[2,4-di(pentan-2-yl)phenoxy]acetyl chloride Chemical compound CCCC(C)C1=CC=C(OCC(Cl)=O)C(C(C)CCC)=C1 NGNBDVOYPDDBFK-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910001096 P alloy Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- GJPVPJBNBCITNZ-UHFFFAOYSA-N [N].[Mn].[Cr] Chemical compound [N].[Mn].[Cr] GJPVPJBNBCITNZ-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 230000008859 change Effects 0.000 description 1
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- 230000001788 irregular Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000010970 precious metal Substances 0.000 description 1
- 238000004881 precipitation hardening Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
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- 230000035945 sensitivity Effects 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
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- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
- 238000012546 transfer 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- C—CHEMISTRY; METALLURGY
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to a microalloy nickel-saving austenitic stainless steel and a manufacturing method thereof, which relate to the field of metal materials and comprise the following chemical components in percentage by mass: c:0.09-0.14%, si:0.19-0.49%, mn:7.1-7.4%, S is less than or equal to 0.0014%, P is less than or equal to 0.014%, ni:1.1-1.9%, cr:17.1-17.9%, cu:0.49-0.99%, N:0.26-0.34%,90×10 ‑4 ％≤Zr+Mg≤130×10 ‑4 And the content of Zr and Mg satisfies the followingThe formula: zr/mg=3-6, the balance being Fe and unavoidable impurities. The invention improves the structure stability, the thermal plasticity, the high-temperature oxidation resistance, the local corrosion resistance and the comprehensive mechanical property of the microalloy nickel-saving austenitic stainless steel, and meets the use requirements of the application fields such as the local corrosion resistance under the conditions of humidity, water medium and ocean environment on the basis of further reducing the cost of raw materials.
Description
Technical Field
The invention relates to the field of metal materials, in particular to a micro-alloy nickel-saving austenitic stainless steel and a manufacturing method thereof.
Background
Austenitic stainless steel is widely used in various fields of national economy due to its excellent mechanical properties and corrosion resistance. However, in recent years, the severe fluctuation of nickel price brings great risk to the production of austenitic stainless steel with high nickel content, and the development of austenitic stainless steel with low nickel content and even no nickel content has been highly focused. The low-nickel austenitic stainless steel has excellent mechanical properties and certain corrosion resistance, and can meet the use requirements under weak corrosion environment conditions, such as the fields of decoration, products and the like. However, stainless steel for decorative, product, humid, marine environments often requires better corrosion resistance, especially seawater localized corrosion resistance, and places higher demands on the localized corrosion resistance of stainless steel. Therefore, the development of low-nickel austenitic stainless steel with excellent local corrosion resistance has very important practical application significance.
Currently, the prior art discloses some advanced studies of austenitic stainless steel. CN1584098A discloses a chemical composition of low N i austenitic stainless steel, in which an alloying method is adopted to further reduce N i content (N i.ltoreq.1.2%) and improve Mn content (8.5% -mn.ltoreq.10.0%), but addition of Cu with a certain content is not considered to improve cold workability, and in addition, component design and technological measures to improve local corrosion resistance are not considered. CN1500894a and CN1704497a disclose chemical compositions of low N i austenitic stainless steel, among which alloying methods are also employed to further reduce N i content (1.0% or less than N i% or less than 5.0%), increase Mn content (7.5% or less than 10.5%), and CN1500894a also allows for adding trace B to improve hot working. However, the N i content is still high and the local corrosion resistance under humid, aqueous, marine environmental conditions is not considered. CN1876882a describes a chemical composition of low N i austenitic stainless steel, in which alloying methods are also employed to further reduce the Ni content (0.6% Ni 1.3%), increase the Mn content (8.5% Mn 12.0%), and also to allow for the addition of trace rare earth elements RE to improve hot workability. But the Ni content is still higher, and meanwhile, rare earth elements are difficult to add in industrial mass production, the yield is unstable, and the structure of the industrial mass production is not facilitated. CN1240839a describes a chemical composition of a low Ni austenitic stainless steel, in which, although alloying methods are also used to further reduce the Ni content (1.0% Ni 4.0%), increase the Mn content (5.0% Mn 11.0%), and also consider treatments with the addition of trace elements B and Ca, the Ni content is still higher and the technique does not add N element, degrading the austenitic stability of the technical product, which is unfavorable for cold forming. In order to solve the problems of the prior art, the invention provides a micro-alloy nickel-saving austenitic stainless steel and a manufacturing method thereof.
Disclosure of Invention
The invention provides a microalloy nickel-saving austenitic stainless steel and a manufacturing method thereof. The method aims to improve the tissue stability, the thermal plasticity, the high-temperature oxidation resistance, the local corrosion resistance and the comprehensive mechanical property of the microalloy austenitic stainless steel, and meets the use requirements of application fields such as the local corrosion resistance under the conditions of humidity, water medium and ocean environment on the basis of further reducing the cost of raw materials.
The invention solves the technical problems, and in a first aspect, provides a microalloy nickel-saving austenitic stainless steel, which comprises the following chemical components in percentage by mass: c:0.09-0.14%, si:0.19-0.49%, mn:7.1-7.4%, S is less than or equal to 0.0014%, P is less than or equal to 0.014%, N i:1.1-1.9%, cr:17.0-18.0%, cu:0.49-0.99%, N:0.26-0.34%,90×10 -4 ％≤Zr+Mg≤130×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
The above components function as follows in microalloy nickel-saving austenitic stainless steel:
c: carbon is an element that strongly stabilizes austenite and enlarges the austenite region in austenitic stainless steel. Carbon interstitials are solid-dissolved in austenite and can significantly improve the strength of austenite by solid-solution strengthening, but carbon is often regarded as a detrimental element in austenite, mainly because the presence of carbon reduces the electrode potential of iron and reduces corrosion resistance in some use or processing processes, such as heating or welding at 450-850 ℃ to produce a phenomenon of chromium depletion in grain boundaries, which reduces the corrosion resistance, particularly intergranular corrosion resistance, of steel. Carbon also increases the pitting tendency of chromium-nickel austenitic stainless steel, so the mass content of C in the present invention is 0.09-0.14%.
Si: silicon is an element that strongly forms ferrite, and in austenitic stainless steel, as the silicon content increases, delta ferrite increases, and the formation of intermetallic compound sigma phase also accelerates and increases, thereby affecting the performance of the steel. To maintain the single austenitic structure of austenitic stainless steel, the nickel and nitrogen content increases as the silicon content increases. Silicon is used as a common deoxidizing element in steel and has synergistic effect with Cu, cr, zr, mg and other elements, so that the corrosion resistance of the steel is improved, and the mass content of S i in the invention is 0.19-0.49%.
Mn: manganese is an important alloying element, the main function of which is to form stable austenite with nitrogen and a certain amount of nickel. The strength of the inconel austenitic stainless steel increases with the manganese content therein. Manganese can improve the thermoplasticity of the chromium-nickel austenitic stainless steel, and has obvious effect when the manganese content is 1.5 percent. Manganese has a strong affinity with sulfur to form MnS, which is beneficial to eliminate the deleterious effects of residual sulfur in steel, but the formation of MnS often results in a reduction in the resistance of the inconel austenitic stainless steel to chloride pitting and crevice corrosion. The sulfur in the steel is reduced to a certain extent, and the adverse effect of manganese can be basically eliminated, so that the mass content of Mn in the invention is 7.1-7.4%.
S: sulfur is considered a detrimental impurity in austenitic stainless steel, the detrimental effects of sulfur being mainly: reducing the thermoplasticity of austenitic stainless steels, affecting the hot workability of the steel, due to precipitation of MnS or (Fe, mn) S along grain boundaries at high temperatures; sulfur also reduces the corrosion resistance of austenitic stainless steel, mnS is easy to dissolve in acid chloride solution and often becomes a corrosion source to cause remarkable reduction of pitting corrosion resistance and crevice corrosion resistance, so the mass content of S is controlled to be less than or equal to 0.0014 percent.
P: austenitic stainless steel with phosphorusSteel is generally considered a detrimental impurity. The detrimental effects of phosphorus are mainly: obviously reduces the corrosion resistance of chromium-nickel austenitic stainless steel to nitric acid with various concentrations in a solid solution state and a sensitized state; obviously enhancing the chromium-nickel austenitic stainless steel in concentrated nitric acid and Cr-containing 5+ The sensitivity of the solid solution intergranular corrosion in the nitric acid reduces the corrosion resistance under the use conditions, so the mass content of P is controlled to be less than or equal to 0.0014 percent in the invention.
N i: the primary role of nickel in austenitic stainless steel is to form and stabilize austenite to achieve a complete austenitic structure, thus providing the steel with a good fit of strength with plasticity, toughness and a range of good process properties. In the nickel content range in which martensitic transformation can occur in steel, as the nickel content increases, the strength of the steel decreases and the plasticity increases due to the decrease in the amount of martensite. For chromium manganese nitrogen austenitic stainless steel with stable austenitic structure, the addition of nickel can further improve its low temperature toughness. Nickel can significantly reduce the cold work hardening tendency of austenitic stainless steel, mainly because nickel increases the stability of austenite, reduces to eliminate martensitic transformation during cold working, and nickel does not have a significant cold work hardening effect on the austenite itself. Nickel improves passivation tendency and thermodynamic stability of austenitic stainless steel, thereby improving uniform corrosion resistance and oxidation resistance medium performance of the alloy; the performance of the reduction resistant medium is further improved with increasing nickel content. In austenitic stainless steels, nickel is an important element that enhances its resistance to through-crystal stress corrosion in some media. The increase in nickel content reduces the solubility of carbon in austenitic steels, enhances the precipitation tendency of carbides, reduces the critical carbon content for intergranular corrosion, i.e., increases the susceptibility to intergranular corrosion, and thus the mass content of N i in the present invention is 1.1 to 1.9%.
Cr: chromium is the most predominant alloying element in austenitic stainless steel. The oxide of Cr can form a compact passivation film to prevent the oxidation of internal materials, on the other hand, the existence of Cr also improves the electrode potential of Fe and can effectively prevent C l - Is effective in inhibiting Fe 3+ To Fe 2+ To form a stable oxide layer fromAnd the stainless steel has corrosion resistance. In austenitic stainless steel, chromium increases the solubility of carbon and decreases the depletion of chromium, and as the chromium content increases, the tendency of formation of sigma phase increases, and when molybdenum is contained in the steel, the increase of chromium content also promotes the formation of chi phase, so that the mass content of Cr in the present invention is 17.1 to 17.9%.
Cu: copper has the effect of remarkably reducing the cold work hardening tendency of austenitic stainless steel and improving cold forming property. Copper and molybdenum can be combined to further improve the corrosion resistance of austenitic stainless steel in reducing media. The reason why the strength of steel is lowered and the plasticity is improved by the increase of solid solution copper is that: copper can obviously increase the stacking fault energy of the chromium-nickel austenitic stainless steel and stabilize an austenitic structure, and the increase of the stacking fault energy prevents incomplete dislocation from forming, is favorable for staggered cross sliding, prevents dislocation accumulation and improves the plasticity of materials. Copper significantly reduces the hot workability of the steel, and is more pronounced when the nickel content in austenitic stainless steel is lower, so that the nickel content should be correspondingly increased when the copper content in the steel is higher. Copper can obviously improve the corrosion resistance of austenitic stainless steel to reducing mediums such as sulfuric acid, phosphoric acid and the like, and when copper and molybdenum are used for composite alloying, the effect is more remarkable, and the addition of copper accelerates the dissolution of molybdenum in the stainless steel to form MoO 4 2- The passivation of chromium in stainless steel and the enrichment of chromium in surface film are strongly promoted, so that the corrosion resistance of steel is improved, and the mass content of Cu in the invention is 0.49-0.99%.
N: the strength of austenitic stainless steel can be obviously improved by solid solution strengthening without obviously damaging the plasticity and toughness of the austenitic stainless steel, and the properties of uniform corrosion resistance, pitting corrosion resistance, crevice corrosion resistance and intergranular corrosion resistance of the steel can be improved by the nitrogen, because the nitrogen is preferentially aggregated along grain boundaries as an active element, the diffusion capacity of carbon atoms and chromium atoms is reduced, thereby inhibiting the precipitation of carbide and delaying the formation of sigma phase and chi phase. The ability of nitrogen to form austenite is equivalent to that of carbon, about 30 times of nickel, and the nitrogen can replace part of nickel in austenitic stainless steel, reduce ferrite content in the steel, make austenite more stable, and even avoid martensite transformation, so the mass content of N in the invention is 0.26-0.34%.
Zr: zirconium is a forming element of strong carbide, is also a forming element of strong deoxidizing element and composite oxysulfide, and the addition of a small amount of zirconium has the effects of degassing, purifying and refining grains, thereby being beneficial to improving the low-temperature performance of stainless steel, improving the stamping performance and remarkably improving the hardenability of the steel when the zirconium is dissolved into austenite. Intergranular corrosion of the steel by the oxidizing medium can be prevented in austenitic steels. Because of the fixed carbon and precipitation hardening effect, the high temperature performance of the heat-strength steel, such as creep strength, can be improved, so that the mass content of Zr and Mg in the invention is 90 multiplied by 10 -4 ％≤Zr+Mg≤130×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6.
Mg: magnesium is a strong deoxidizing element and a composite oxysulfide forming element, and can reduce the number of inclusions in steel, reduce the size, uniformly distribute, improve the shape and the like. The trace magnesium can improve the size and distribution of carbide in stainless steel, the carbide particles are fine and uniform, the formed MgO inclusion has the effect of pinning austenite grain boundary, and has good control effect on the grain size, so the mass content of Zr and Mg in the invention is 90 multiplied by 10 -4 ％≤Zr+Mg≤130×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6.
The beneficial effects of the invention are as follows:
(1) The invention uses the molten iron which is smelted by the laterite-nickel ore and is rich in chromium and nickel as the raw material for smelting stainless steel, thereby saving noble metal elements Cr and Ni; the industrial pure iron can reduce P, S and other impurities, which is beneficial to reducing harmful impurity P in stainless steel and reducing the content of other impurities.
(2) Cr and C required in the invention can be matched through ferrochrome, and C can release heat through oxidization in smelting, thereby achieving the effects of heating and being beneficial to the smelting process; the prepared microalloy nickel-saving austenitic stainless steel has strong tissue stability, good high-temperature thermoplastic property and high-temperature oxidation resistance, and more excellent local corrosion resistance and comprehensive mechanical property of seawater and the like.
On the basis of the technical scheme, the invention can be improved as follows.
Further, it comprises the following components in percentage by massThe content comprises the following chemical components: c:0.09-0.10%, si:0.19-0.25%, mn:7.1-7.2%, S is less than or equal to 0.0011%, P is less than or equal to 0.011%, ni:1.1 to 1.4 percent, cr:17.0-17.5%, cu:0.49-0.59%, N:0.26-0.30%,90×10 -4 ％≤Zr+Mg≤105×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
Further, the paint comprises the following chemical components in percentage by mass: c:0.10-0.14%, si:0.25-0.49%, mn:7.2-7.4%, S is less than or equal to 0.0010%, P is less than or equal to 0.010%, ni:1.4-1.9%, cr:17.5-17.9%, cu:0.59-0.99%, N:0.30-0.34%,100×10 -4 ％≤Zr+Mg≤110×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
Further, the paint comprises the following chemical components in percentage by mass: the composite material comprises the following chemical components in percentage by mass: c:0.10%, si:0.25%, mn:7.2%, S:0.0010%, P:0.010%, N i:1.4%, cr:17.5%, cu:0.59%, N:0.30%, mg:0.0025%, zr:0.0080%, and the balance of Fe and unavoidable impurities.
The second aspect provides a method for preparing a microalloy nickel-saving austenitic stainless steel, comprising the following steps:
step 1, taking the following raw materials in parts by weight: 30-35% of ultra-low P industrial pure iron, 15-20% of high-carbon ferrochrome and 50-60% of molten iron smelted by laterite-nickel ore; firstly adding the ultra-low P industrial pure iron and the high-carbon ferrochrome into an intermediate frequency furnace for melting, and then adding molten iron smelted by the laterite-nickel ore into the intermediate frequency furnace to obtain a smelting microalloy nickel-saving austenitic stainless steel raw material;
step 2: and (3) refining, continuously casting, rolling and carrying out solution treatment on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step (1) in sequence to obtain the microalloy nickel-saving austenitic stainless steel.
In the step 1, the following raw materials are taken according to the weight ratio: 30-34% of ultra-low P industrial pure iron, 15-20% of high-carbon ferrochrome and 52-60% of molten iron smelted by laterite-nickel ore.
Further, in step 1, the weight contents of the chemical components P and C in the ultra-low P industrial pure iron are respectively: p is less than or equal to 0.0050 percent, and C is less than or equal to 0.001 percent; the high-carbon ferrochrome comprises the following chemical components in percentage by weight: cr is more than or equal to 60 percent, C is less than or equal to 9.5 percent.
Further, in the step 1, the chemical components Cr and P in the molten iron smelted by the laterite-nickel ore respectively have the following weight contents: cr is more than or equal to 60 percent, P is less than or equal to 0.03 percent.
Further, in the step 2, the specific steps of refining, continuous casting, rolling and solution treatment are sequentially carried out on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step 1:
step 2-1, refining: carrying out external refining on the smelting microalloy nickel-saving austenitic stainless steel raw material in an LF furnace, and carrying out C, si, cr, N i, cu, P and S alloy fine adjustment and Zr, mg and N microalloying treatment according to chemical components in the microalloy nickel-saving austenitic stainless steel to obtain microalloyed stainless steel;
step 2-2, continuous casting: continuously casting the microalloyed stainless steel under the conditions that the tundish temperature is 1465-1480 ℃ and the working pulling speed is 1.05-1.20m/min to obtain a continuous casting blank;
step 2-3, rolling: rolling the continuous casting blank at 1150-1250 ℃ to obtain a hot-rolled black skin coil;
step 2-4, solution treatment: and heating the hot-rolled black skin coil to 1050-1150 ℃ and enabling the solid solution time to be 0.6-1.0mm/min, and cooling to obtain the microalloy nickel-saving austenitic stainless steel.
In step 2-1, the refining time is 45-90mi < n >, and the tapping temperature is more than or equal to 1530 ℃.
Drawings
FIG. 1 is a diagram of the morphology of inclusions in austenitic stainless steel according to the conventional technique of the present invention;
FIG. 2 is a graph showing the morphology of inclusions in austenitic nickel-saving stainless steel according to the present invention;
FIG. 3 is an optical micrograph of a prior art microalloyed austenitic stainless steel of the present invention;
FIG. 4 is an optical micrograph of a microalloyed austenitic stainless steel prepared in accordance with the present invention;
FIG. 5 is a constant electrode potential saturation current density of a microalloyed austenitic stainless steel of the prior art;
FIG. 6 is a constant electrode potential saturation current density of a microalloyed nickel-saving austenitic stainless steel prepared in accordance with the present invention;
FIG. 7 is a potentiodynamic polarization curve of a prior art microalloyed austenitic stainless steel of the present invention;
FIG. 8 is a potentiodynamic polarization curve of a microalloy nickel-saving austenitic stainless steel prepared in accordance with the present invention;
FIG. 9 is an AC impedance diagram I of a microalloyed austenitic stainless steel made in accordance with the conventional technique of the present invention;
FIG. 10 is an AC impedance diagram II of a microalloyed austenitic stainless steel made in accordance with the conventional technique of the present invention;
FIG. 11 is a fitted circuit diagram of a microalloyed austenitic stainless steel made in accordance with the conventional technique of the present invention and in accordance with the present invention.
Detailed Description
The principles and features of the present invention are described below with examples given for the purpose of illustration only and are not intended to limit the scope of the invention.
Example 1
The embodiment relates to a microalloy nickel-saving austenitic stainless steel, which comprises the following chemical components in percentage by mass: 0.09wt% C, 0.19wt% Si, 7.1wt% Mn, 0.0010wt% S, 0.010wt% P, 1.1wt% NI, 17.1wt% Cr, 0.49wt% Cu, 0.26wt% N, 0.0025wt% Mg, 0.0075wt% Zr, the balance being Fe and unavoidable impurities.
The embodiment relates to a preparation method of a micro-alloy nickel-saving austenitic stainless steel, which comprises the following steps:
step 1: the ingredients were dosed as follows: the ultra-low P industrial pure iron is used as smelting base material, and the mass ratio is 30%; adding high-carbon ferrochrome, wherein the mass ratio is 20%; then adding molten iron smelted by using laterite nickel ore, wherein the mass ratio is 50%. Wherein P in the ultra-low P industrial pure iron is less than or equal to 0.0035wt% and C is less than or equal to 0.005wt%. Cr in the high-carbon ferrochrome is more than or equal to 60wt percent, and C is less than or equal to 6.5wt percent. Cr of molten iron smelted by laterite nickel ore is more than or equal to 60wt% and P is less than or equal to 0.01wt%. Melting ultra-low P industrial pure iron and high-carbon ferrochrome by adopting an intermediate frequency furnace, and then adding molten iron (the mass ratio is 50%) smelted by using laterite-nickel ore to obtain a microalloy nickel-saving austenitic stainless steel raw material, wherein P in the smelted stainless steel is less than or equal to 0.014wt%;
step 2: and (3) refining, continuously casting, rolling and carrying out solution treatment on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step (1) in sequence to obtain the microalloy nickel-saving austenitic stainless steel.
Preferably, in step 2, the specific steps of refining, continuous casting, rolling and solution treatment are sequentially performed on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in step 1, wherein the specific steps are as follows:
step 2-1: LF external refining: slag is removed before tapping, and the slag is cleaned as much as possible; tapping the white slag, wherein a small amount of lime and fluorite can be used for adjusting the reducibility and fluidity of the slag; the tapping temperature is 1530 ℃; firstly electrifying to melt the top slag, and then performing alloy fine adjustment and microalloying to obtain the chemical components in percentage by weight: 0.09wt% C, 0.19wt% Si, 7.1wt% Mn, 0.0010wt% S, 0.010wt% P, 1.1wt% Ni, 17.1wt% Cr, 0.49wt% Cu, 0.26wt% N, 0.0025wt% Mg, 0.0075wt% Zr, and the balance being Fe; the smelting time of the LF refining furnace is 45 min.
Step 2-2: continuous casting: the tundish temperature is 1465 ℃; the working pulling speed is 1.05 m/min; the water quantity of the wide surface of the crystallizer is 175m 3 And/h, the water quantity of the narrow surface is 20m 3 And/h, the temperature difference of water inlet and water outlet is 5 ℃; the crystallizer adopts non-sinusoidal vibration, the vibration frequency is 140CPM, and the amplitude is 3.0mm; the crystallizer casting powder is high nitrogen casting powder.
Step 2-3: rolling: heating and hot rolling the continuous casting blank to obtain a hot-rolled black skin coil; the temperature of the hot rolling was 1150 ℃.
Step 2-4: solution treatment: and carrying out solution treatment after hot rolling, wherein the solution treatment temperature is 1050 ℃, the solution time is 0.6 mm/min, the air cooling and water cooling time is 60 min, and the room-temperature water cooling is carried out after the air cooling, so that the micro-alloy nickel-saving austenitic stainless steel is obtained.
Example 2
The embodiment relates to a microalloy nickel-saving austenitic stainless steel, which comprises the following chemical components in percentage by mass: 0.10wt% C, 0.25wt% Si, 7.2wt% Mn, 0.0011wt% S, 0.011wt% P, 1.4wt% Ni, 17.5wt% Cr, 0.59wt% Cu, 0.30wt% N, 0.0025wt% Mg, 0.0080wt% Zr, the balance being Fe and unavoidable impurities.
The embodiment relates to a preparation method of a micro-alloy nickel-saving austenitic stainless steel, which comprises the following steps:
step 1: the ingredients were dosed as follows: the ultra-low P industrial pure iron is used as smelting base material, and the mass ratio is 34%; adding high-carbon ferrochrome, wherein the mass ratio is 14%; then adding molten iron smelted by using laterite nickel ore, wherein the mass ratio is 52%. Wherein P in the ultra-low P industrial pure iron is less than or equal to 0.0050wt% and C is less than or equal to 0.01wt%. Cr in the high-carbon ferrochrome is more than or equal to 60wt percent, and C is less than or equal to 9.5wt percent. Cr of molten iron smelted by laterite nickel ore is more than or equal to 60wt% and P is less than or equal to 0.03wt%. Melting ultra-low P industrial pure iron and high-carbon ferrochrome by adopting an intermediate frequency furnace, and then adding molten iron smelted by using laterite-nickel ore to obtain a microalloy nickel-saving austenitic stainless steel raw material, wherein P in the smelted stainless steel is less than or equal to 0.015wt%;
step 2: and (3) refining, continuously casting, rolling and carrying out solution treatment on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step (1) in sequence to obtain the microalloy nickel-saving austenitic stainless steel.
Preferably, in step 2, the specific steps of refining, continuous casting, rolling and solution treatment are sequentially performed on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in step 1, wherein the specific steps are as follows:
step 2-1: LF external refining: slag is removed before tapping, and the slag is cleaned as much as possible; tapping the white slag, wherein a small amount of lime and fluorite can be used for adjusting the reducibility and fluidity of the slag; the tapping temperature is 1630 ℃; firstly electrifying to melt the top slag, and then performing alloy fine adjustment and microalloying to obtain the chemical components in percentage by weight: 0.10wt% C, 0.25wt% Si, 7.2wt% Mn, 0.0011wt% S, 0.011wt% P, 1.4wt% Ni, 17.5wt% Cr, 0.59wt% Cu, 0.30wt% N, 0.0025wt% Mg, 0.0080wt% Zr, and the balance being Fe; the smelting time of the LF refining furnace is 60 min.
Step 2-2: continuous casting: tundish temperature 1470 ℃; the working pulling speed is 1.10 m/min; the water quantity of the wide surface of the crystallizer is 185m 3 And/h, the water quantity of the narrow surface is 24m 3 And/h, wherein the water inlet and outlet temperature difference is 6 ℃; the crystallizer adopts non-sinusoidal vibration, the vibration frequency is 140CPM, and the amplitude is 3.0mm; the crystallizer casting powder is high nitrogen casting powder.
Step 2-3: rolling: heating and hot rolling the continuous casting blank to obtain a hot-rolled black skin coil; the temperature of the hot rolling is 1200 ℃.
Step 2-4: solution treatment: and carrying out solution treatment after hot rolling, wherein the solution treatment temperature is 1100 ℃, the solution time is 0.9 mm/min, the air cooling and water cooling time is 100 min, and the room-temperature water cooling is carried out after the air cooling, so that the micro-alloy nickel-saving austenitic stainless steel is obtained.
Example 3
The embodiment relates to a microalloy nickel-saving austenitic stainless steel, which comprises the following chemical components in percentage by mass: 0.14wt% of C, 0.49wt% of Si, 7.4wt% of Mn, 0.0014wt% of S, 0.014wt% of P, 1.9wt% of NI, 17.9wt% of Cr, 0.89wt% of Cu, 0.34wt% of N, 0.0020wt% of Mg, 0.0090wt% of Zr, and the balance of Fe and unavoidable impurities.
The embodiment relates to a preparation method of a micro-alloy nickel-saving austenitic stainless steel, which comprises the following steps:
step 1: the ingredients were dosed as follows: using ultra-low P industrial pure iron as smelting base material, wherein the mass ratio is 35%; adding high-carbon ferrochrome, wherein the mass ratio is 15%; then adding molten iron smelted by using laterite nickel ore, wherein the mass ratio is 60%. Wherein P in the ultra-low P industrial pure iron is less than or equal to 0.0050wt% and C is less than or equal to 0.01wt%. Cr in the high-carbon ferrochrome is more than or equal to 60wt percent, and C is less than or equal to 9.5wt percent. Cr of molten iron smelted by laterite nickel ore is more than or equal to 60wt% and P is less than or equal to 0.03wt%. Melting ultra-low P industrial pure iron (35% by mass) and high-carbon ferrochrome (15% by mass) by adopting an intermediate frequency furnace, and then adding molten iron (60% by mass) smelted by using laterite-nickel ore to obtain a smelting microalloy nickel-saving austenitic stainless steel raw material, wherein P in the smelted stainless steel is less than or equal to 0.012wt%;
step 2: and (3) refining, continuously casting, rolling and carrying out solution treatment on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step (1) in sequence to obtain the microalloy nickel-saving austenitic stainless steel.
Preferably, in step 2, the specific steps of refining, continuous casting, rolling and solution treatment are sequentially performed on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in step 1, wherein the specific steps are as follows:
step 2-1: LF external refining: slag is removed before tapping, and the slag is cleaned as much as possible; tapping the white slag, wherein a small amount of lime and fluorite can be used for adjusting the reducibility and fluidity of the slag; the tapping temperature is 1730 ℃; firstly electrifying to melt the top slag, and then performing alloy fine adjustment and microalloying to obtain the chemical components in percentage by weight: 0.14wt% C, 0.49wt% Si, 7.4wt% Mn, 0.0014wt% S, 0.014wt% P, 1.9wt% NI, 17.9wt% Cr, 0.99wt% Cu, 0.34wt% N, 0.0020wt% Mg, 0.0090wt% Zr, the balance being Fe; the smelting time of the LF refining furnace is 90 min.
Step 2-2: continuous casting: tundish temperature 1480 ℃; the working pulling speed is 1.20 m/min; the water quantity of the wide surface of the crystallizer is 195m 3 And/h, the narrow surface water quantity is 25m 3 And/h, the temperature difference of water inlet and water outlet is 7 ℃; the crystallizer adopts non-sinusoidal vibration, the vibration frequency is 140CPM, and the amplitude is 3.0mm; the crystallizer casting powder is high nitrogen casting powder.
Step 2-3: rolling: heating and hot rolling the continuous casting blank to obtain a hot-rolled black skin coil; the temperature of the hot rolling was 1250 ℃.
Step 2-4: solution treatment: and carrying out solution treatment after hot rolling, wherein the solution treatment temperature is 1150 ℃, the solution time is 1.0mm/min, the air cooling and water cooling time is 120 min, and the room-temperature water cooling is carried out after the air cooling, so that the micro-alloy nickel-saving austenitic stainless steel is obtained.
The microalloyed nickel-saving austenitic stainless steel prepared in the following manner in connection with example 1 was subjected to various tests on the characteristics of inclusion and corrosion resistance thereof, and the results were as follows:
(1) Inclusion characteristics and mechanism of formation thereof
The morphology of the inclusions in the test samples was observed by SEM and the results are shown in fig. 1 and 2. As can be seen from FIG. 1, the inclusions in the conventional austenitic stainless steel have a long or irregular shape, and the size of the inclusions is about 2 to 5. Mu.m. As can be seen from FIG. 2, the inclusions in the microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention are spherical or equiaxed, and the size of the inclusions is about 1-3. Mu.m. The fine and spherical inclusions have an important positive effect on improving the plasticity and toughness of austenitic stainless steel.
According to the basic principle of metallurgical thermodynamics, zr and Mg are strong oxide forming elements, and Zr and Mg are adopted for composite deoxidation, so that the free oxygen content in molten steel is removed. ZrO (ZrO) 2 Has a density of 5.68g/cm 3 Greater than A l 2 O 3 Density (3.97 g/cm) 3 ) In particular ZrO 2 And the density of molten steel (7.15 g/cm) 3 ) More closely, so that once a stable oxide is formed at high temperature, zrO 2 Can float uniformly in molten steel to make Al 2 O 3 Collide and gather on the surface of molten steel to become a component part of steel slag, and part Al which cannot float upwards 2 O 3 Large inclusions in the form of clusters remain in the steel. The conductivity of the oxide is a key factor in its movement in the molten steel. As can be seen from the conventional research results, A l in molten steel 2 O 3 The driving force of the movement is greater than ZrO 2 Driving force for the movement. ZrO during the refining by energization 2 The particles tend to repel each other and hardly agglomerate, al 2 O 3 Then the particles are easy to collide with each other to form large particles which float to the surface of molten steel and are absorbed by the covering agent on the surface of molten steel. Thus, in comparison with conventional A l, si deoxidation, a fine, dispersed composite oxide can be formed by Zr, mg composite deoxidation, as demonstrated by the experimental results of fig. 2.
In addition, mnS and ZrO 2 Having very similar lattice constants, the specific data are shown in table 1. Due to MnS and ZrO 2 There is a good lattice match which will lower the interface energy between the two. The lower interface energy results in better adhesion between grains of different interfaces. This further demonstrates that no streak or string sulphide is formed in the test sampleFor reasons of (2). This is because MnS tends to be present in preformed ZrO 2 The sulfide precipitated on the particles is thus refined, spheroidized and dispersed. Thereby being beneficial to the improvement of the plasticity and the toughness of the Zr and Mg composite deoxidized ferrite stainless steel.
TABLE 1MnS and ZrO 2 Is a lattice constant of (2)
(2) Corrosion active inclusion density
The conventional austenitic stainless steel and the microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention were examined for corrosion-active inclusion, and microscopic structure micrographs of the examination were shown in fig. 3 and 4. And the densities of corrosive active inclusions in the conventional austenitic stainless steel and the microalloy nickel-saving austenitic stainless steel prepared in example 1 of the present invention were statistically analyzed.
The surface of the conventional austenitic stainless steel is black, pits are generated by dissolution of corrosive active inclusions, the surface of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is basically free of corrosive active inclusions, and the density of the corrosive active inclusions on the surface of a sample is counted. The density of corrosive active inclusion in the conventional austenitic stainless steel is 0.56/mm 2 Whereas the density of corrosive active inclusion in the microalloy nickel-saving austenitic stainless steel prepared in example 1 of the present invention is 0.23/mm 2 . As shown by the statistical analysis result, the density of corrosive active inclusion obtained in the austenitic stainless steel is obviously lower than that of the conventional austenitic stainless steel after the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention which is smelted by adopting laterite-nickel ore is treated by adding Zr and other elements. It is reported in literature that MnS inclusions themselves or surrounding areas are extremely soluble in sodium chloride solution, induce pitting, and have high corrosion activity. After composite deoxidization of Zr and the like, mnS inclusions with high corrosion activity in the steel are modified into inclusions containing composite type, zrO 2 The inclusions such as MgO and the like have higher stability and are added in sodium chlorideThe solution has higher corrosion resistance, so that the density of corrosive active inclusion in steel is reduced after Zr and Mg are subjected to composite deoxidation.
(3) Corrosion test
The microalloy nickel-saving austenitic stainless steel prepared in the example 1 is subjected to electrochemical testing by using a Zahner Zennium electrochemical workstation, a standard three-electrode system is selected, the invention steel is used as a working electrode, a platinum sheet is used as an auxiliary electrode, and a Saturated Calomel Electrode (SCE) is used as a reference electrode. Electrostatic electrode potential method: the stability of the resistance to general corrosion at maximum saturation current density was identified under electrostatic potential conditions in a simulated environment. Meanwhile, a potentiostatic polarization test is carried out, the potential of the potentiostatic polarization curve test is 300mV, the test time is 3600s, and the saturation current density Imax is recorded after the test is completed. The potentiodynamic polarization curve test was performed at a scan rate of 0.5mV/s, with a scan range of-0.6 to 1.2V relative to Open Circuit Potential (OCP), with 3.5wt.% NaC l solution being the test solution chosen.
Constant potential polarization corrosion tests of conventional austenitic stainless steel and microalloy nickel-saving austenitic stainless steel prepared in example 1 of the present invention were conducted by referring to corrosion evaluation methods, and saturation current density results of conventional austenitic stainless steel and microalloy nickel-saving austenitic stainless steel prepared in example 1 of the present invention are shown in fig. 5 and 6. The smaller the saturation current density value is under the same corrosion time, which shows that the corrosion resistance of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is better. The saturation current density value of the conventional austenitic stainless steel is 2.77 mA.cm 2 Whereas the saturation current density of the microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention was 0.342 mA.cm 2 The saturation current density of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is 2.428 mA.cm lower than that of the traditional austenitic stainless steel 2 . Therefore, the research and development of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention are carried out based on laterite nickel ore, the types and the forms of inclusions are effectively changed through multielement composite deoxidization of Zr, mg and the like, the density of corrosive active inclusions is obviously reduced, and the constant potential polarization saturation current density value is obviousThe local corrosion resistance is obviously better than that of the traditional austenitic stainless steel.
Fig. 7 and 8 are potentiodynamic polarization curves of conventional austenitic stainless steel and microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention in 3.5wt.% NaC solution. The self-corrosion potential and corrosion current density of the test sample can be obtained through the potentiodynamic polarization curve test and Tafe l fitting, and the potentiodynamic polarization curve test is used for judging the change trend of the corrosion rate of the sample and the corrosion reaction mechanism.
The corresponding corrosion potential and corrosion current density values for conventional austenitic stainless steel and the microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention are shown in table 2. The self-corrosion potential values of the conventional austenitic stainless steel and the microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention were-0.0065V and 0.013V, respectively. Corrosion current density values of the conventional austenitic stainless steel and the microalloy nickel-saving austenitic stainless steel prepared in example 1 of the present invention were 8.71×10, respectively -5 mA·cm 2 And 7.67×10 -5 mA·cm 2 . As can be seen from table 2: the self-corrosion potential of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is higher than that of the conventional austenitic stainless steel, and the corrosion current density value of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is smaller than that of the conventional austenitic stainless steel. The more positive the self-corrosion potential means that the better the thermodynamic stability of the metal, the less prone to corrosion. The smaller the corrosion current density value means the slower the rate at which the metal will corrode. The microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention has smaller corrosion current density and more positive self-corrosion potential, so that the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention has better corrosion resistance than the conventional austenitic stainless steel.
TABLE 2 fitting results of the potentiodynamic polarization of austenitic stainless steels of conventional and inventive techniques
(4) AC impedance
Samples were electrochemically tested in 3.5wt.% NaCl solution using a Zahner Zennium electrochemical workstation. The test was performed using a three electrode system with a platinum mesh as the counter electrode, the sample as the working electrode, and a Saturated Calomel Electrode (SCE) as the reference electrode. Electrochemical Impedance Spectroscopy (EIS) tests were performed by applying an amplitude of 10mV in the frequency range of 0.01 to 100000Hz, and experimental data were fitted by zsampwin software.
Fig. 9 and 10 are ac impedance diagrams of a conventional austenitic stainless steel and a microalloyed nickel-saving austenitic stainless steel prepared in example 1 of the present invention in a 3.5wt.% NaCl solution. From the Nyquist plot it can be seen that the two stainless steels have similarly shaped curves: all are incomplete capacitive arcs, and the corrosion mechanism is similar, and an Rs (Q1 (R1 (Q2R 2))) equivalent circuit diagram is selected as shown in FIG. 11. In the experiment, rs is a solution resistor, Q1 is an electric double layer capacitor, R1 is a passivation film resistor, Q2 is a passivation film capacitor, and R2 is a charge transfer resistor. The magnitude of the arc-tolerant diameter of the Nyquist plot reflects the corrosion rate of stainless steel, and generally the larger the arc-tolerant diameter, the better the corrosion resistance. Two stainless steels were fitted according to zsampwin software and the fitting results are shown in table 3. As can be seen from table 2: the passivation film resistance R1 and the polarization resistance R2 of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention are higher than those of the conventional austenitic stainless steel, which shows that the stability of the passivation film is obviously improved, and the passivation film is not easy to thin in a corrosive medium, so that the corrosion resistance of the microalloy nickel-saving austenitic stainless steel prepared in the embodiment 1 of the invention is better than that of the conventional austenitic stainless steel.
TABLE 3 fitting results of the alternating current impedance of austenitic stainless steels of conventional and inventive techniques
In conclusion, the invention utilizes the molten iron which is smelted by the laterite-nickel ore and is rich in chromium and nickel as smelting raw materials, saves precious metal N i, and obtains good mechanical properties by utilizing low-cost elements such as silicon, manganese, chromium and the like; the invention combines and adds zirconium, magnesium and other elements, improves the toughness and the welding performance at the same time; compared with the conventional austenitic stainless steel, the constant electrode potential saturation current density of the microalloy nickel-saving austenitic stainless steel is obviously reduced, and the seawater corrosion resistance is more excellent than that of the conventional austenitic stainless steel, on one hand, the microstructure and morphology of the microalloy nickel-saving austenitic stainless steel are obviously changed due to the fact that the composite deoxidizing elements Zr and Mg are used for obviously modifying corrosion active inclusions, the density of the corrosion active inclusions is greatly reduced due to the fact that MnS with high corrosion activity is replaced by composite oxysulfide, the seawater partial corrosion resistance is obviously improved, and on the other hand, the corrosion resistance of a matrix is improved due to N i and Cr elements brought in laterite nickel ore, and the seawater corrosion resistance is improved to a certain extent.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. The microalloy nickel-saving austenitic stainless steel is characterized by comprising the following chemical components in percentage by mass: c:0.09-0.14%, si:0.19-0.49%, mn:7.1-7.4%, S is less than or equal to 0.0014%, P is less than or equal to 0.014%, ni:1.1-1.9%, cr:17.1-17.9%, cu:0.49-0.99%, N:0.26-0.34%,90×10 -4 ％≤Zr+Mg≤130×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
2. The microalloyed nickel-saving austenitic stainless steel of claim 1, comprising the following chemical components in mass percent: c:0.09-0.10%, si:0.19-0.25%, mn:7.1-7.2%, S is less than or equal to 0.0011%, P is less than or equal to 0.011%, ni:1.1 to 1.4 percent, cr:17.1-17.5%, cu:0.49-0.59%, N:0.26-0.30%,90×10 -4 ％≤Zr+Mg≤105×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
3. The microalloyed nickel-saving austenitic stainless steel of claim 1, comprising the following chemical components in mass percent: c:0.10-0.14%, si:0.25-0.49%, mn:7.2-7.4%, S is less than or equal to 0.0010%, P is less than or equal to 0.010%, ni:1.4-1.9%, cr:17.5-17.9%, cu:0.59-0.99%, N:0.30-0.34%,100×10 -4 ％≤Zr+Mg≤110×10 -4 And the content of Zr and Mg satisfies the following formula: zr/mg=3-6, the balance being Fe and unavoidable impurities.
4. The microalloyed nickel-saving austenitic stainless steel of claim 1, comprising the following chemical components in mass percent: the composite material comprises the following chemical components in percentage by mass: c:0.10%, si:0.25%, mn:7.2%, S:0.0010%, P:0.010%, ni:1.4%, cr:17.5%, cu:0.59%, N:0.30%, mg:0.0025%, zr:0.0080%, and the balance of Fe and unavoidable impurities.
5. A method for preparing a microalloyed nickel-saving austenitic stainless steel according to any of claims 1 to 4, characterized in that it comprises the steps of:
step 1, taking the following raw materials in parts by weight: 30-35% of ultra-low P industrial pure iron, 15-20% of high-carbon ferrochrome and 50-60% of molten iron smelted by laterite-nickel ore; firstly adding the ultra-low P industrial pure iron and the high-carbon ferrochrome into an intermediate frequency furnace for melting, and then adding molten iron smelted by the laterite-nickel ore into the intermediate frequency furnace to obtain a smelting microalloy nickel-saving austenitic stainless steel raw material;
step 2: and (3) refining, continuously casting, rolling and carrying out solution treatment on the smelting microalloy nickel-saving austenitic stainless steel raw material obtained in the step (1) in sequence to obtain the microalloy nickel-saving austenitic stainless steel.
6. The method for preparing the microalloy nickel-saving austenitic stainless steel according to claim 5, wherein in the step 1, the following raw materials are taken according to the weight ratio: 30-34% of ultra-low P industrial pure iron, 15-20% of high-carbon ferrochrome and 52-60% of molten iron smelted by laterite-nickel ore.
7. The method for preparing a microalloy nickel-saving austenitic stainless steel according to claim 5 or 6, wherein in step 1, the chemical components P and C in the ultra-low P industrial pure iron are respectively in weight contents of: p is less than or equal to 0.0050 percent, and C is less than or equal to 0.001 percent; the high-carbon ferrochrome comprises the following chemical components in percentage by weight: cr is more than or equal to 60 percent, C is less than or equal to 9.5 percent.
8. The method for preparing the microalloy nickel-saving austenitic stainless steel according to claim 5 or 6, wherein in the step 1, the chemical components Cr and P in the molten iron smelted by the laterite-nickel ore are respectively as follows by weight: cr is more than or equal to 60 percent, P is less than or equal to 0.03 percent.
9. The method for preparing the microalloy nickel-saving austenitic stainless steel according to claim 5 or 6, wherein in the step 2, the specific steps of refining, continuous casting, rolling and solution treatment are sequentially performed on the raw material of the smelting microalloy nickel-saving austenitic stainless steel obtained in the step 1:
step 2-1, refining: carrying out external refining on the smelting microalloy nickel-saving austenitic stainless steel raw material in an LF furnace, and carrying out microalloying treatment on the microalloy nickel-saving austenitic stainless steel raw material and Zr, mg and N according to the chemical component C, si, cr, ni, cu, P, S alloy fine adjustment in the microalloy nickel-saving austenitic stainless steel to obtain microalloyed stainless steel;
step 2-2, continuous casting: continuously casting the microalloyed stainless steel under the conditions that the temperature of a tundish is 1465-1480 ℃ and the working pulling speed is 1.05-1.20m/min to obtain a continuous casting blank;
step 2-3, rolling: rolling the continuous casting blank at 1150-1250 ℃ to obtain a hot-rolled black skin coil;
step 2-4, solution treatment: and heating the hot-rolled black skin coil to 1050-1150 ℃ and enabling the solid solution time to be 0.6-1.0mm/min, and cooling to obtain the micro-alloy nickel-saving austenitic stainless steel.
10. The method for preparing the microalloy nickel-saving austenitic stainless steel according to claim 9, wherein in the step 2-1, the refining time is 45-90min, and the tapping temperature is more than or equal to 1530 ℃.
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