High-strength and toughness non-quenched and tempered steel and preparation method thereof

A technology of non-quenched and tempered steel with high strength and toughness, which is applied in the field of high-strength and toughness non-quenched and tempered steel and its preparation. , Improve the strength and toughness, strengthen the effect of the matrix

Active Publication Date: 2019-02-01
CENT IRON & STEEL RES INST +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In view of the above analysis, the present invention aims to provide a high-strength toughness non-quenched and tempered steel and a preparation method thereof. By increasing the N content, reasonably adding Mn, Cr and V and precisely controlling the V / N mass ratio, the problems in the prior art are solved. It is difficult to improve the comprehensive performance of non-quenched and tempered steel by taking into account the performance of the alloy and the cost of use

Method used

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  • High-strength and toughness non-quenched and tempered steel and preparation method thereof
  • High-strength and toughness non-quenched and tempered steel and preparation method thereof
  • High-strength and toughness non-quenched and tempered steel and preparation method thereof

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preparation example Construction

[0045] Specifically, the preparation method of high-strength toughness non-quenched and tempered steel may include the following steps:

[0046] Step 1: Using a vacuum induction furnace to smelt high-strength toughness non-quenched and tempered steel raw materials to obtain alloy ingots.

[0047] Step 2: Forge the alloy ingot into a Φ90mm round bar, change the Φ90mm round bar into a Φ40mm round bar, the initial forging temperature is higher than 1150°C, and the final forging temperature is between 840-1000°C;

[0048] Specifically, the initial forging temperature is 1180-1200°C, and the final forging temperature is between 860-950°C.

[0049] Step 3: Cool the forged bar to 700-750°C in air, and then cool it to below 450°C at a cooling rate of 1-2°C / s to obtain a uniform bainite structure.

Embodiment 1

[0051] This embodiment provides a high-strength toughness non-quenched and tempered steel, including: C: 0.25%; Si: 0.30%; Mn: 1.82%; Cr: 0.50%, S: 0.053%; P: 0.0055%; V: 0.11%; N: 0.025%; V / N: 4.40, the rest is iron and unavoidable impurities.

[0052] The preparation method of this non-quenched and tempered steel is as follows:

[0053] (1) Smelting: use a vacuum induction furnace to smelt the raw materials of high-strength toughness non-quenched and tempered steel to obtain alloy ingots.

[0054] (2) Forging: Forge the alloy ingot into a Φ90mm round bar, change the Φ90mm round bar into a Φ40mm round bar, the initial forging temperature is 1190°C, and the final forging temperature is 880°C.

[0055] (3) Controlled cooling after forging: Cool the forged bar to 700-750°C in the air, and then cool it to below 450°C at a cooling rate of 1-2°C / s.

Embodiment 2

[0057] This embodiment provides a high-strength toughness non-quenched and tempered steel, which includes, by mass percentage: C: 0.25%; Si: 0.24%; Mn: 1.81%; Cr: 0.52%, S: 0.054%; P: 0.0056%; V: 0.12%; N: 0.029%; V / N: 4.14, and the balance is iron and unavoidable impurities.

[0058] The preparation method of this non-quenched and tempered steel is as follows:

[0059] (1) Smelting: use a vacuum induction furnace to smelt the raw materials of high-strength toughness non-quenched and tempered steel to obtain alloy ingots.

[0060] (2) Forging: Forge the alloy ingot into a Φ90mm round bar, change the Φ90mm round bar into a Φ40mm round bar, the initial forging temperature is 1200°C, and the final forging temperature is 885°C.

[0061] (3) Controlled cooling after forging: Cool the forged bar to 700-750°C in the air, and then cool it to below 450°C at a cooling rate of 1-2°C / s.

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Abstract

The invention discloses high-strength and toughness non-quenched and tempered steel and a preparation method thereof, and belongs to the technical field of structural alloy steel. The N content is increased, Mn, Cr and V are reasonably added, and the V/N mass ratio is accurately controlled, so that the problem of incapability of combining strength, toughness and use cost of non-quenched and tempered steel in the prior art are solved. The high-strength and toughness non-quenched and tempered steel is prepared from the following components according to mass percent: 0.23 to 0.27% of C, 0.22 to 0.35% of Si, 1.81 to 1.90% of Mn, 0.50 to 0.55% of Cr, 0.045 to 0.06% of S, less than or equal to 0.02% of P, 0.11 to 0.14% of V, 0.025 to 0.040% of N and the balance of Fe and inevitable impurities. The tensile strength of the high-strength and toughness non-quenched and tempered steel is greater than or equal to 950 MPa, and the Charpy impact work KU2 (20 DEG C) is greater than or equal to 55 J.The preparation method of the high-strength and toughness non-quenched and tempered steel comprises the steps of smelting, forging and cooling after forging. The high-strength and toughness non-quenched and tempered steel can be used for automobile safety parts.

Description

technical field [0001] The invention belongs to the technical field of alloy structural steel, and relates to a high-strength toughness non-quenched and tempered steel and a preparation method thereof. Background technique [0002] Non-quenched and tempered steel can obtain higher strength without quenching and tempering after forging or rolling. It is a green steel that can improve production efficiency, reduce production costs, and is conducive to energy saving, emission reduction and environmental protection. It is widely used in automobiles , construction machinery, agricultural machinery and other fields. [0003] At present, the pearlite-ferrite non-quenched and tempered steel is widely used and widely used. Its disadvantage is that its toughness is lower than that of quenched and tempered steel at the same strength level. Compared with pearlitic-ferritic non-quenched and tempered steel, bainitic non-quenched and tempered steel has better toughness at the same strengt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/24C22C38/38C22C38/60C21D8/06
CPCC21D8/065C21D2211/002C22C38/001C22C38/002C22C38/02C22C38/24C22C38/38C22C38/60
Inventor 王瑞珍陈雪慧杨才福师仲然段美琪
Owner CENT IRON & STEEL RES INST
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