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A kind of preparation method of ultra-high strength duplex heterogeneous stainless steel

An ultra-high-strength, stainless steel technology, applied in metal rolling and other directions, can solve the problems of inability to achieve ultra-high-strength steel, low yield strength of martensitic stainless steel, and achieve improved plasticity, grain size, and low production costs. Effect

Active Publication Date: 2022-05-24
NANJING UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, due to the low yield ratio of martensitic stainless steel prepared by this method, it cannot reach the level of ultra-high strength steel

Method used

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  • A kind of preparation method of ultra-high strength duplex heterogeneous stainless steel
  • A kind of preparation method of ultra-high strength duplex heterogeneous stainless steel
  • A kind of preparation method of ultra-high strength duplex heterogeneous stainless steel

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preparation example Construction

[0030] like figure 1 As shown, a preparation method of ultra-high-strength duplex stainless steel mainly includes the following steps:

[0031] The first step: heat treatment isomerization: a) Put the martensitic stainless steel into the vacuum quenching furnace, heat it up to 1350℃-1400℃ with the furnace and keep it for 0.5-1.5 hours to make the structure uniform. b) Oil quenching in the two-phase region is performed on the stainless steel after heat preservation to obtain a delta ferrite + martensite isomer structure with high strength and hardness.

[0032] The second step: deformation strengthening and toughening: the stainless steel with delta ferrite + martensite structure is rolled at 250℃-350℃, and the sample is placed in a muffle furnace for heating for 10-20 minutes before each pass of rolling. , the cumulative rolling amount is 40%-80%.

Embodiment 1

[0034] The chemical composition is C 0.21%, Si 0.92%, Mn 0.49%, P 0.026%, S 0.015%, Cr 12.50%, Ni 0.35%, and the balance is Fe stainless steel ingot.

[0035] (1) Heat treatment isomerization:

[0036] The above chemical composition is C 0.21%, Si 0.92%, Mn 0.49%, P 0.026%, S 0.015%, Cr 12.50%, Ni 0.35%, and the balance is Fe. The stainless steel ingot is cut with a size of 80mm×40mm× 8mm small block, put it into the vacuum quenching furnace, and heat it up to 1350 °C with the furnace at 10 °C / min and keep it for 0.5 hours to obtain the delta ferrite + austenite structure. Vacuum oil quenching of stainless steel to obtain delta ferrite + martensite structure with high strength and hardness, such as figure 2 shown.

[0037] (2) Deformation strengthening and toughening: The stainless steel with delta ferrite + martensite structure is rolled at 400 °C, and the reduction amount per pass is 0.1 mm, and the sample is placed at 300 °C before each pass of rolling. Heating in a res...

Embodiment 2

[0039] The chemical composition is C 0.21%, Si 0.92%, Mn 0.49%, P 0.026%, S 0.015%, Cr 12.50%, Ni 0.35%, and the balance is Fe stainless steel ingot.

[0040] (1) Heat treatment isomerization:

[0041] The above chemical composition is C 0.21%, Si 0.92%, Mn 0.49%, P 0.026%, S 0.015%, Cr 12.50%, Ni 0.35%, and the balance is Fe. The stainless steel ingot is cut out with a thickness of 8mm. , put it into a vacuum quenching furnace, heat it up to 1350 °C with the furnace at 10 °C / min and keep it for 0.5 hours to obtain a delta ferrite + austenite structure. Vacuum oil quenching is performed on stainless steel to obtain a delta ferrite + martensite structure with high strength and hardness.

[0042] (2) Deformation strengthening and toughening: The stainless steel with delta ferrite + martensite structure is rolled at room temperature, the reduction amount of each pass is 0.1mm, and the cumulative reduction amount is 60%, and the obtained martensite Stainless steel has poor plast...

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Abstract

The invention belongs to the field of material preparation, specifically a method for preparing ultra-high-strength dual-phase heterogeneous stainless steel, comprising the following steps: Step (1): isomerization heat treatment; isomerizing martensitic stainless steel in the two-phase region Heat treatment, control and control to obtain δ ferrite + martensite dual-phase structure; step (2): deformation strengthening and toughening; the product obtained in step (1) is subjected to warm rolling treatment in the tempering temperature zone, control martensite structure carbon distribution, introducing high-density interstitial carbon atom segregation on the dual-phase heterogeneous interface of δ ferrite and martensite, and obtaining a ferrite / martensite dual-phase structure with a layer thickness of 50-100 nm, resulting in a strength > 2.5 GPa duplex heterogeneous martensitic stainless steel. In the present invention, the warm rolling of the stainless steel with δ-ferrite + martensite structure with a relatively large amount of deformation can refine the crystal grains and generate a large number of dislocations, so as to achieve the purpose of strengthening and toughening the deformation; finally, the tensile strength can be obtained above 2.4GPa , Ultra-high-strength duplex heterogeneous stainless steel with a fracture toughness of more than 5%.

Description

technical field [0001] The invention belongs to the field of material preparation, in particular to a preparation method of ultra-high-strength dual-phase heterogeneous stainless steel. Background technique [0002] As the most common structural material, steel materials are widely used in construction, transportation, petrochemical and other fields. As a kind of steel material, martensitic stainless steel is mainly characterized by good hardenability, which can be strengthened by heat treatment processes such as quenching and tempering to obtain higher strength, hardness and wear resistance. Therefore, martensitic stainless steel is widely used in cutting tools, steam turbine blades, large engine block blades, bearings and wear-resistant parts, large castings used in the manufacture of hydropower station equipment, pump and valve castings and other fields. In recent years, with the development of welding and heat treatment technology, stainless steel has received extensive...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D6/00C21D1/18C21D1/773C21D8/00B21B3/02
CPCC21D6/00C21D1/18C21D1/773C21D8/005B21B3/02C21D2211/005C21D2211/008
Inventor 周浩徐涛高波肖礼容
Owner NANJING UNIV OF SCI & TECH