Medium manganese steel with heterogeneous lamellar structure and preparation method of medium manganese steel

A lamellar structure and heterogeneous technology, applied in the field of medium manganese steel materials, can solve problems such as low heating rate, product bending deformation, and lower industrial production conditions

Active Publication Date: 2021-11-16
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The object of the present invention is to propose a method for preparing medium manganese steel that is heat-treated by two-stage heating. In this heat treatment mode, a low heating rate can be used to obtain Alternately composed he

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  • Medium manganese steel with heterogeneous lamellar structure and preparation method of medium manganese steel
  • Medium manganese steel with heterogeneous lamellar structure and preparation method of medium manganese steel
  • Medium manganese steel with heterogeneous lamellar structure and preparation method of medium manganese steel

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preparation example Construction

[0048] According to the technical scheme of the present invention, the preparation method of manganese steel in some specific heterogeneous lamellar structures comprises the following steps:

[0049] (1) after forging an ingot comprising iron, carbon and manganese, heat it at 1100-1300° C. for 24-36 hours to perform homogenization treatment, and hot-roll the forging obtained after the homogenization treatment to obtain a hot-rolled steel plate;

[0050] (2) Heat the obtained hot-rolled steel plate to the austenite single-phase region of 800-900°C for austenitization treatment, keep it warm for 10-60 minutes, and then cool it to the two-phase region of ferrite and cementite for heat preservation , to obtain pearlite structure, and continue to cool to room temperature;

[0051] (3) Rapidly austenitize the hot-rolled steel plate after pearlite transformation through a two-stage heat treatment. The two-stage heat treatment includes: first slowly heating the hot-rolled steel plate af...

Embodiment 1

[0060] The specific composition is Fe-0.39C-3.69Mn (wt.%) steel through vacuum melting and forging to form 250*250*40mm 3 Forging; take 100×40×26mm from the center of the forging 3 The square forgings are heated to 1250°C in an argon atmosphere, and held for 24 hours for homogenization; the homogenized forgings undergo 5 to 8 rolling passes to obtain hot-rolled plates with a thickness of 6mm, and the final rolling temperature is greater than 850°C. After rolling, air-cool to room temperature to form a martensitic matrix structure.

[0061] The steel plate after hot rolling is carried out as follows: figure 1 The shown two-stage heat treatment, the specific treatment steps are as follows:

[0062] (1) The hot-rolled steel plate was kept in a muffle furnace at 800°C for 10 minutes for austenitization, then moved to a salt bath furnace at 570°C and kept for 6 hours for complete pearlite transformation, and then water quenched to room temperature;

[0063] (2) After the pearlit...

Embodiment 2

[0069] The specific composition is Fe-0.39C-3.69Mn (wt.%) steel through vacuum melting and forging to form 250*250*40mm 3 Forging; take 100×40×26mm from the center of the forging 3 The square forgings were heated to 1200°C in an argon atmosphere, and held for 36 hours for homogenization; the homogenized forgings were passed through 9 rolling passes to obtain hot-rolled plates with a thickness of 6mm, and the final rolling temperature was greater than 900°C. Air-cooled to room temperature to form a martensitic matrix structure.

[0070] The steel plate after hot rolling is carried out as follows: figure 1 Shown heat treatment, specific processing steps are as follows:

[0071] (1) Heat the hot-rolled steel plate in a muffle furnace at 850°C for 6 minutes for austenitization, then move it to a salt-bath furnace at 550°C and hold it for 12 hours, then water quench to room temperature to obtain pearlite with a higher degree of Mn partitioning ;

[0072] (2) After the pearlite ...

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Abstract

The invention discloses medium manganese steel with a heterogeneous lamellar structure and a preparation method of the medium manganese steel. The medium manganese steel is provided with the heterogeneous lamellar structure formed by overlapping Mn-rich retained austenite nanosheets and Mn-poor martensite nanosheets. The preparation method of the medium manganese steel comprises the steps that the medium manganese steel with pearlite as an initial structure is subjected to two-stage heat treatment, wherein in the first-stage heat treatment, the temperature is increased to the preheating temperature lower than the austenite forming temperature at the heating rate of less than 30 DEG C/s, and heat preservation is conducted for preheating treatment; in the second-stage heat treatment, the preheating temperature is increased to the austenite reversal temperature at the heating rate of less than 30 DEG C/s, and heat preservation is conducted for austenite reverse treatment; and finally, tempering treatment is conducted. Through two-stage heating treatment at the lower heating rate, the medium manganese steel with the same microstructure and mechanical property as a rapid heating process can be prepared, the industrial production conditions are remarkably reduced, and a new technical route is provided for preparing large and thick steel plates with heterogeneous structures in traditional industrial production.

Description

technical field [0001] The invention relates to the technical field of medium manganese steel materials. Background technique [0002] Advanced high-strength steels are widely used as structural materials in the automotive industry, among which medium manganese steel is one of the most promising third-generation high-strength steels. The typical microstructure of medium manganese steel is ferrite / martensite and retained austenite, which achieves the matching between strength and elongation through the transformation-induced plasticity of retained austenite, and the austenite reverse transformation process Austenite stabilizing elements (such as carbon (C) and manganese (Mn)) can be partitioned into austenite by annealing in the two-phase region, thereby improving the stability of austenite so that it can be retained at room temperature, However, in order to obtain sufficiently stable austenite, a higher annealing temperature or a longer annealing time is often required to e...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/14C22C38/22C22C38/24C22C38/26C22C38/28C22C38/34C22C38/38C21D1/18C21D6/00C21D8/02
CPCC22C38/02C22C38/38C22C38/34C22C38/24C22C38/04C22C38/26C22C38/28C22C38/22C22C38/12C22C38/14C21D1/18C21D6/002C21D6/005C21D6/008C21D8/0205C21D8/0221C21D8/0247C21D2211/001C21D2211/008
Inventor 熊志平杨德振张超程兴旺
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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