Martensite stainless steel and preparation method thereof

A technology of martensitic stainless steel and ferrite, applied in the field of iron and steel metallurgy, to achieve the effect of excellent comprehensive mechanical properties and good salt spray corrosion resistance

Inactive Publication Date: 2018-10-12
CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide martensitic stainless steel and its preparation method, to solve the problem of poor corrosion resistance of martensitic stainless steel and the need to add precious metals molybdenum and tungsten to improve its corrosion resistance in the prior art

Method used

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preparation example Construction

[0043] Another technical solution of the present invention is to provide the preparation method of the martensitic stainless steel, which includes the following steps: smelting molten steel with the chemical composition, casting, hot rolling, and annealing to obtain it.

[0044] Among them, hot rolling is a key step. In the present invention, the steel billet is heated to 1050-1250°C for soaking, which can ensure that a single austenite phase can be obtained after soaking; hot rolling is carried out at a temperature range above 850°C, which can ensure that the austenite single phase of the above-mentioned stainless steel is formed during the hot rolling process. interval.

[0045] The martensitic stainless steel of the present invention is a martensite structure after hot rolling, and the martensite is transformed into a structure of ferrite + carbide after annealing, and has excellent drawing performance, hot top forging performance, machinability and salt resistance Fog cor...

Embodiment 1

[0046] Embodiment 1 Preparation of martensitic stainless steel of the present invention

[0047] The mass fraction of smelting chemical composition is C: 0.12%, Si=0.41%, Mn=0.39%, P=0.015%, S=0.002%, Ni=0.30%, Cr=13.5%, Cu=0.08%, V=0.12% , Al=0.015%, N=0.016% and the balance is Fe, (KFF=9.1, Cr+2.6*V-11*C-7*N=12.4) stainless steel, poured into a square billet of 200×200mm; The cast slab is heated to 1080°C for soaking, the rolling start temperature is 1050°C, hot rolled to a φ32mm round bar, and the final rolling temperature is 920°C; the steel bar is heated to 860°C and kept for 8 hours, the furnace is cooled to 300°C, and air cooled to room temperature.

[0048] Brinell hardness of annealed steel rod HB=178; pitting potential E' b100 =122mV, see figure 1 , wherein the comparison example is 12Cr13 martensitic stainless steel; the surface is in the state of car polish, and there is no rust after 72 hours of neutral salt spray test, see figure 2 .

Embodiment 2

[0049] Embodiment 2 Preparation of martensitic stainless steel of the present invention

[0050] The mass fraction of smelting chemical composition is C: 0.25%, Si=0.36%, Mn=0.68%, P=0.020%, S=0.004%, Ni=0.23%, Cr=14.8%, Cu=1.5%, V=0.6% , Al=0.006%, N=0.004% balance is Fe, (KFF=6.9, Cr+2.6*V-11*C-7*N=13.6) stainless steel, poured into a square billet of 200×200mm; The cast slab is heated to 1250°C for soaking, the rolling start temperature is 1180°C, hot rolled to a φ60mm round bar, and the final rolling temperature is 980°C; the steel bar is heated to 830°C and kept for 10 hours, the furnace is cooled to 300°C, and air cooled to room temperature.

[0051] Brinell hardness of annealed steel bar HB=191; pitting potential E' b100 =127mV, the surface is in the state of car polish, and no rust occurs after 72 hours of neutral salt spray test.

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Abstract

The invention relates to martensite stainless steel and a preparation method thereof and belongs to the technical field of ferrous metallurgy. The problems to be solved are that martensite stainless steel is poor in corrosion resisting performance, and precious metal molybdenum and tungsten need to be added for improving the corrosion resisting performance of the martensite stainless steel in theprior art. According to the technical scheme, the martensite stainless steel comprises chemical components including, by weight, 0.03%-0.25% of C, smaller than or equal to 1.0% of Si, 0.1%-2.0% of Mn,smaller than or equal to 0.035% of P, smaller than or equal to 0.020% of S, smaller than or equal to 1.5% of Ni, 11.5%-15.0% of Cr, 0.05%-2.0% of Cu, 0.05%-0.6% of V, smaller than or equal to 0.03% of Al, 0.002%-0.05% of N and the balance Fe. The martensite stainless steel has excellent comprehensive mechanical performance and good salt-spray corrosion resisting performance, and is very suitablefor being used in parts of industry like home appliances with the high requirement for corrosion resisting performance.

Description

technical field [0001] The invention relates to martensitic stainless steel and a preparation method thereof, belonging to the technical field of iron and steel metallurgy. Background technique [0002] Martensitic stainless steel is a kind of Fe-Cr-C ternary alloy. Its mechanical properties can be adjusted by heat treatment (quenching, tempering) to obtain the required toughness and plasticity, and the hardness can also be increased to improve the resistance of steel. Abrasion and abrasion resistance. Martensitic stainless steel can reach a wide range of strength after heat treatment, and the yield strength can range from 275MPa in the annealed state to 1900MPa in the quenching + tempering (high carbon class). However, due to its low chromium content [w (Cr) = 12% ~ 14%] and high carbon content, the corrosion resistance of martensitic stainless steel is not as good as other stainless steel grades, which limits its further application. For example, low-carbon martensitic s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/42C22C38/46C22C38/06C22C38/20C22C38/24C22C38/58C22C38/38C21D8/00C21D1/26
CPCC21D1/26C21D8/005C21D2211/005C22C38/02C22C38/04C22C38/06C22C38/20C22C38/24C22C38/38C22C38/42C22C38/46C22C38/58
Inventor 郑淮北宋令玺白青青韩逊
Owner CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
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