Process method for improving impact toughness of double-phase stainless steel

A technology of duplex stainless steel and process method, which is applied in the field of stainless steel processing, can solve the problems of duplex stainless steel such as reduced toughness, high critical temperature, and poor toughness, and achieve the effects of improving overall toughness, improving impact toughness, and high impact toughness

Active Publication Date: 2019-05-21
CENT IRON & STEEL RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above analysis, the embodiment of the present invention aims to provide a process for improving the impact toughness of duplex stainless steel, which solves the problem of poor toughness of duplex stainless steel at low temperature and high critical temperature at which the toughness of duplex stainless steel is significantly reduced in the prior art. technical problem

Method used

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  • Process method for improving impact toughness of double-phase stainless steel
  • Process method for improving impact toughness of double-phase stainless steel
  • Process method for improving impact toughness of double-phase stainless steel

Examples

Experimental program
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Effect test

Embodiment 1

[0053] In this example, solid solution treatment is carried out at 1050-1100°C, and the austenite content is controlled at 45-55% and the N α / N γ ≤0.12.

[0054] S32750 duplex stainless steel molten steel is smelted by EAF+AOD+LF, poured into steel ingots, subjected to compression deformation along the longitudinal direction with a deformation ratio of 1.5, and then subjected to elongation deformation along the longitudinal direction with a deformation ratio of 7.0 to make a forged billet.

[0055] Cut S32750 duplex stainless steel plate-shaped test billet, its chemical composition and content (wt%) are: C: 0.02; Cr: 25.22; Ni: 7.15; Mo: 3.94; N: 0.27; Mn: 0.63; Si: 0.48; Cu: 0.22; the rest is Fe and unavoidable impurities. After solution treatment at different temperatures (1050, 1070, 1100, 1150, 1200°C), duplex stainless steels with different structures are prepared. The transverse V-type impact toughness was measured at room temperature, 0°C, -10°C, -40°C, -60°C, -100°C...

example 2

[0070] In this embodiment, the aspect ratio of the austenite is controlled between 1.0 and 4.0 by controlling rolling deformation.

[0071] S32750 duplex stainless steel molten steel is smelted by EAF+AOD+LF, poured into steel ingots, subjected to compression deformation along the longitudinal direction with a deformation ratio of 1.5, and then subjected to elongation deformation along the longitudinal direction with a deformation ratio of 7.0 to make a forged billet.

[0072] Cut S32750 duplex stainless steel plate blank, its chemical composition and content (wt%) are: C: 0.02; Cr: 25.22; Ni: 7.15; Mo: 3.94; N: 0.27; Mn: 0.63; Si: 0.48; Cu : 0.22; the rest is Fe and unavoidable impurities), and according to Figure 2-1 Transverse or longitudinal rolling as shown, marked as "transverse rolling" and "longitudinal rolling", with a deformation ratio of 1.5, was made into test billets with different austenitic aspect ratios, the ratio of lateral deformation / longitudinal deformatio...

example 3

[0084] In this embodiment, the aspect ratio of the austenite is controlled between 1.0 and 4.0 by controlling the deformation ratio of forging+rolling.

[0085] S32750 duplex stainless steel molten steel is smelted by EAF+AOD+LF, poured into steel ingots, subjected to compression deformation along the longitudinal direction with a deformation ratio of 1.5, and then subjected to elongation deformation along the longitudinal direction with a deformation ratio of 7.0 to make a forged billet.

[0086] Cut S32750 duplex stainless steel square, its chemical composition and content (wt%) are: C: 0.02; Cr: 25.22; Ni: 7.15; Mo: 3.94; N: 0.27; Mn: 0.63; Si: 0.48; Cu: 0.22 ; the rest are Fe and unavoidable impurities), according to Figure 3-1 As shown, respectively carry out forging compression (longitudinal compression deformation ratio 3.0) and forging elongation (longitudinal elongation deformation ratio 1.5) along the longitudinal direction to make a slab, and then roll along the lo...

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Abstract

The invention relates to a process method for improving the impact toughness of double-phase stainless steel, and belongs to the technical field of stainless steel machining. The technical problems that double-phase stainless steel in the prior art is poor in toughness during low temperature, and the critical temperature at which the toughness of the double-phase stainless steel is remarkably reduced is high are solved. The method includes the following process steps that S1, metal raw materials are smelted into molten steel; S2, the molten steel is smelted into a continuous casting billet ora steel ingot with a continuous casting or die casting method; S3, the continuous casting billet or the steel ingot is heated at the temperature of 1,150-1,250 DEG C, hammer cogging is carried out, and a forging-state billet is manufactured; S4, the forging billet is heated at the temperature of 1,050-1,250 DEG C, the total deformation ratio of a finished product is larger than or equal to 5.0, the transverse deformation ratio / the longitudinal deformation ratio is larger than or equal to 0.30, and the length-width ratio of austenite is controlled to be 1.0-4.0; and S5, the product is subjectedto solution treatment, and the content of the austenite is controlled to be 46-55%. The process method is used for improving the low-temperature toughness of the double-phase stainless steel and reducing the critical temperature at which the toughness of the double-phase stainless steel is remarkably reduced.

Description

technical field [0001] The invention relates to the technical field of stainless steel processing, in particular to a process for improving the impact toughness of duplex stainless steel. Background technique [0002] The structure of duplex stainless steel is composed of a certain proportion of ferrite phase and austenite phase, and has the mechanical properties of ferritic stainless steel and austenitic stainless steel: it has high strength and good toughness Good mechanical properties, corrosion resistance and weldability in various environments, duplex stainless steel in pulp and paper, petrochemical, chemical tankers, onshore and offshore oil and gas industry, pharmaceutical and food industry, construction industry be widely used. [0003] As the excellent mechanical and corrosion resistance properties of duplex stainless steel are more fully understood, its application and potential application fields continue to expand, and its application scope is further extended t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/00C22C38/02C22C38/04C22C38/42C22C38/44
Inventor 宋志刚丰涵郑文杰朱玉亮苏诚王宝顺
Owner CENT IRON & STEEL RES INST
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