Super-high-strength martensite aging stainless steel resistant to seawater corrosion

An ultra-high-strength, martensitic technology, applied in ultra-high-strength maraging stainless steel, the manufacture of high-toughness structural parts, and high-strength fields, it can solve the problems of low strength and poor corrosion resistance that cannot meet the reliability requirements of structural parts to achieve excellent seawater corrosion resistance, ensure strength, toughness and corrosion resistance, and reduce production costs

Active Publication Date: 2018-02-02
INST OF METAL RESEARCH - CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Traditional high-strength stainless steels such as PH13-8Mo, 15-5PH, etc. have good corrosion resistance, but their strength is too low to meet the reliability requirements of structural parts in harsh environments.
Custom475 with a higher strength level, although its tensile strength has reached 2000MPa, its plasticity is obviously low (the elongation is about 5%), which seriously limits its application prospects
Ultra-high-strength steels with a strength exceeding 1600MPa include low-alloy ultra-high-strength steel 300M and cobalt-containing 18Ni maraging steel. These steels have high strength and toughness and can meet the design requirements of industrial structural parts. , the extremely poor corrosion resistance restricts its application

Method used

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  • Super-high-strength martensite aging stainless steel resistant to seawater corrosion
  • Super-high-strength martensite aging stainless steel resistant to seawater corrosion
  • Super-high-strength martensite aging stainless steel resistant to seawater corrosion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] According to the following nominal composition (wt.%): C: 0.02%, Cr: 13.0%, Ni: 4.5%, Co: 6.0%, Mo: 4.5%, Ti: 2.0%, Si: 0.1%, Mn: 0.1% , P: 0.01%, S: 0.01%, Fe: the balance, after batching and mixing, it is melted in a vacuum induction melting furnace, and after being cast into an ingot, heat processing and heat treatment are carried out according to the following process:

[0050] (1) Forging in the austenite single-phase region, the forging ratio is 8, and air-cooled to room temperature after forging;

[0051] (2) Hot rolling after forging, the initial rolling temperature is 1200°C, the final rolling temperature is 900°C, and the total cumulative reduction of hot rolling is 80%;

[0052] (3) Heat treatment system: solution treatment (1100°C for 1.5h, air cooling to room temperature), cryogenic treatment (-196°C for 6h in liquid nitrogen), aging treatment (480°C for 12h, air cooling).

[0053] After heat treatment, the material is processed into a 10*10*5mm sample, an...

Embodiment 2

[0056] On the basis of Example 1, the content of some alloy elements was appropriately adjusted, and the Cr / Ni equivalent ratio and the type and quantity of precipitated phases were changed to obtain better microstructure and mechanical properties than Example 1.

[0057] According to the following nominal composition (wt.%): C: 0.015%, Cr: 13.0%, Ni: 7.0%, Co: 6.0%, Mo: 4.5%, Ti: 2.7%, Si: 0.1%, Mn: 0.1% , P: 0.01%, S: 0.01%, Fe: the balance, after batching and mixing, it is melted in a vacuum induction melting furnace. The smelted ingot is subjected to thermal processing and heat treatment according to the process conditions described in Example 1.

Embodiment 3

[0060] On the basis of Example 1 and Example 2, the content of some alloying elements was further adjusted to obtain a qualified structure (full martensitic structure), and by changing the type and content of the precipitated phase, the mechanical properties were better than The novel maraging stainless steels of Example 1 and Example 2.

[0061] According to the following nominal composition (wt.%): C: 0.015%, Cr: 13.0%, Ni: 7.0%, Co: 6.0%, Mo: 4.5%, Ti: 2.1%, Si: 0.1%, Mn: 0.1% , P: 0.01%, S: 0.01%, Fe: the balance, after batching and mixing, it is melted in a vacuum induction melting furnace. The smelted ingot is subjected to thermal processing and heat treatment according to the process conditions described in Example 1.

[0062] The metallographic structure of the material after heat treatment is as follows: Figure 4 As shown, a qualified full martensitic structure has been successfully obtained through the adjustment of the content of alloying elements, and the age ha...

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Abstract

The invention belongs to the field of high-strength stainless steel and provides martensite aging stainless steel which is high in toughness and good in corrosion resistance. The strength of the martensite aging stainless steel reaches 2000 MPa or above. The specific chemical constituents of the martensite aging stainless steel comprise, by weight percentage, less than or equal to 0.03% of C, 13.0-14.0% of Cr, 5.5-7.0% of Ni, 5.5-7.5% of Co, 3.0-5.0% of Mo, 1.9-2.5% of Ti, less than or equal to 0.1% of Si, less than or equal to 0.1% of Mn, less than or equal to 0.01% of P, less than or equal to 0.01% of S and the balance Fe. The stainless steel has the excellent seawater corrosion resistance; the pitting potential Epit is greater than or equal to 0.15 V, and high tough fit is achieved; sigma b is greater than or equal to 2000 MPa, sigma 0.2 is greater than or equal to 1700 MPa, delta is greater than or equal to 8%, and psi is greater than or equal to 40%; the martensite aging stainlesssteel is applicable to manufacturing of high-strength and high-toughness structural components used in a chloridion-containing rigorous corrosion environment such as seawater; the content of preciousmetal Co in the steel is low; material production cost is effectively lowered; and wide application prospect is achieved.

Description

technical field [0001] The invention belongs to the field of high-strength stainless steel, and specifically relates to an ultra-high-strength maraging stainless steel resistant to seawater corrosion, which is mainly suitable for the manufacture of high-strength and high-toughness structural parts used in harsh corrosion environments containing chloride ions such as seawater . Background technique [0002] As a traditional alloy system, stainless steel has been widely used in machinery, nuclear industry, aerospace, construction and civil fields due to its unique properties (stainlessness) since its appearance in 1900. Stainless steel plays an important role in economy and technology. Therefore, with the development of science and technology and the progress of human civilization, it has become an inevitable trend to optimize and improve the comprehensive performance of stainless steel. [0003] For the performance optimization of stainless steel, the core research route is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/52C22C38/50C22C38/44C21D8/00
CPCC21D6/004C21D8/005C21D2211/008C22C38/44C22C38/50C22C38/52C21D1/18C21D6/04C21D7/13C21D8/0226C22C38/02C22C38/04C21D6/005C21D6/007C21D6/008
Inventor 王威田家龙单以银严伟杨柯
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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