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A kind of low-carbon microalloy steel with gradient ultrafine grain structure and preparation method thereof

A technology of ultra-fine grain and alloy steel, applied in the field of low-carbon micro-alloy steel with gradient ultra-fine grain structure and its preparation, can solve the problems of unfavorable steel materials, complex process control, and inability to undergo phase transformation of samples, so as to improve the comprehensive performance effect

Active Publication Date: 2019-11-12
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the control of the process program is relatively complicated. The sample surface needs to be processed before the laser surface heat treatment. The parameters such as laser spot, lap rate, scanning rate, and laser power need to cooperate with each other within a certain range to form a good size gradient structure. In addition, limitations Because the sample cannot undergo phase transformation during heat treatment, it is not conducive to the application of steel materials that are prone to phase transformation during heat treatment

Method used

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  • A kind of low-carbon microalloy steel with gradient ultrafine grain structure and preparation method thereof
  • A kind of low-carbon microalloy steel with gradient ultrafine grain structure and preparation method thereof
  • A kind of low-carbon microalloy steel with gradient ultrafine grain structure and preparation method thereof

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Embodiment 1

[0036]A low-carbon microalloy steel plate with a gradient ultra-fine grain structure, which contains chemical components and the mass percentages of each chemical component are: C is 0.12%, Mn is 1.35%, Si is 0.49%, Nb is 0.035%, and Ti is 0.019% %, the balance is Fe and unavoidable impurities.

[0037] A method for preparing a low-carbon microalloy steel plate with a gradient ultrafine grain structure, specifically comprising the following steps:

[0038] (1) Melting: according to the chemical composition and ingredients of the above-mentioned low-carbon microalloy steel plate with gradient ultra-fine grain structure, it is added to a vacuum induction melting furnace, melted at a temperature of 1650 ° C, and cast to obtain a 50 kg round ingot;

[0039] (2) Forging: heat a 50kg round ingot at 1150°C for 3 hours, forge it, and air-cool it to room temperature to obtain a 100mm×100mm square ingot. Cut the square ingot into 30mm×100mm×100mm to obtain a cut square ingot;

[0040] ...

Embodiment 2

[0047] A kind of low-carbon microalloy steel plate with gradient ultra-fine grain structure. After the same smelting, forging, and conventional hot rolling as in Example 1, the hot-rolled steel plate is heated at 950 ° C, kept for 15 minutes, and asynchronously rolled at 800 ° C. The ratio is 2:1, the reduction is 75%, and a steel plate with a thickness of 1.50 mm is obtained, and then water quenched to room temperature to obtain a low-carbon microalloy steel plate with a gradient ultrafine grain structure. Its mechanical performance parameters are: tensile strength is 937MPa, yield strength is 662MPa, elongation is 21.6%, uniform elongation is 18%, and yield ratio is 0.71. The low-carbon microalloy steel plate with gradient ultra-fine grain structure prepared in this embodiment is along the thickness direction 1 / 8 (a), 2 / 8 (b), 3 / 8 (c), 4 / 8 (d), 5 / 8 ( The metallographic microstructure corresponding to the regions e), 6 / 8(f), 7 / 8(g) and 8 / 8(h) are shown in image 3 , the grai...

Embodiment 3

[0049] A kind of low-carbon microalloy steel plate with gradient ultra-fine grain structure. After the same smelting, forging, and conventional hot rolling as in Example 1, the hot-rolled steel plate is heated at 950°C, kept for 15 minutes, and asynchronously rolled at 750°C. The ratio is 2:1, the reduction is 75%, and a steel plate with a thickness of 1.50 mm is obtained, and then water quenched to room temperature to obtain a low-carbon microalloy steel plate with a gradient ultrafine grain structure. Its mechanical performance parameters are: tensile strength is 905MPa, yield strength is 628MPa, elongation is 16.8%, uniform elongation is 13.4% and yield ratio is 0.73. The low-carbon microalloy steel plate with gradient ultra-fine grain structure prepared in this embodiment is along the thickness direction 1 / 8 (a), 2 / 8 (b), 3 / 8 (c), 4 / 8 (d), 5 / 8 ( The metallographic microstructure corresponding to the regions e), 6 / 8(f), 7 / 8(g) and 8 / 8(h) are shown in Figure 5 , the grain ...

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Abstract

A gradient ultra-fine grain structure low carbon microalloy steel and a preparation method thereof, belonging to the technical field of metal material processing and preparation. The gradient ultra-fine grain structure low carbon microalloy steel contains the components and their mass percentages: C 0.08~0.15%, Mn 0.5~1.5%, Si 0~1.0%, Nb 0~0.05%, Ti 0~0.1%, The balance is Fe and inevitable impurities. The preparation method includes smelting, forging, conventional hot rolling and asynchronous hot rolling. In the asynchronous hot rolling, the plate is heated to 950-1200°C, kept for 10-30 minutes, and quenched with water to room temperature to prepare the product. This method combines the asynchronous rolling compression-shear composite mechanism and the strain-induced ferrite phase transformation mechanism, introduces strain gradients and dynamic phase transformation gradients, and obtains ultra-fine grains while also obtaining a structure with a gradient distribution of grain size in the thickness direction. shape, thereby effectively increasing the strength and hardness of the metal material while maintaining the plasticity and toughness of the metal material, and improving the overall performance of the material.

Description

technical field [0001] The invention belongs to the technical field of metal material processing and preparation, and in particular relates to a low-carbon microalloy steel with gradient ultrafine grain structure and a preparation method thereof. Background technique [0002] Improving the plasticity, toughness and formability of high-strength steel or ultra-high-strength steel is the key direction of "new generation steel materials" research. As a representative of the "new generation of steel materials", ultra-fine-grained steel has significant strengthening and toughening characteristics. Through the ultra-fine grain size, the strength and toughness can be improved at the same time. The amount of steel has a good application prospect. However, the generation of a large number of defects is inevitable in the process of ultra-refinement of grains. Along with the significant increase in strength level, the plasticity, toughness and work hardening ability of the material usu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/12C22C38/14C21D8/02C22C33/04
CPCC21D8/02C22C33/04C22C38/02C22C38/04C22C38/12C22C38/14
Inventor 蔡明晖刘姗李文霞苏俊华
Owner NORTHEASTERN UNIV LIAONING