Method for enhancing strength and toughness of medium-carbon V steel

A technology of steel strength and toughness, which is applied in the field of improving the strength and toughness of medium carbon V steel, can solve the problems of high production process cost, weak market competitiveness, and reduced steel toughness, so as to reduce heat treatment procedures, improve cost performance and market competitiveness, The effect of improving toughness

Active Publication Date: 2014-12-10
WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the high price of V-containing alloys or VN alloys, the current production process for achieving solid solution strengthening through V atom replacement is high in cost and weak in market competitiveness
On the other hand, after the V content in the steel increases, especially the V in the steel 4 C 3 When the number increases and the particle size increases, it will reduce the toughness of the steel

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] First, during electric furnace smelting, N element is added, so that the main components of the steel in this example (referred to as Invention Steel A) are controlled as follows: [C]: 0.33%, [Si]: 0.38%, [Mn]: 1.17% , [V]: 0.10%, [N]: 0.0091%, and the rest are iron and impurities. The addition of N elements can be realized by the following method: connect N to the bottom blowing argon (Ar) gas pipeline of the refining furnace ladle 2 Gas valve, blowing N into the molten steel during the refining process 2 gas.

[0028] Secondly, the size of the continuous casting slab smelted in the electric furnace: 200×200mm, the heating temperature of the casting slab is in the range of 1170-1195°C for 55 minutes, and the Φ55mm round steel is rolled.

[0029] Utilizing the sealed state of the rolling raceway, the rolled piece is allowed to stay in the range of 860-868°C for 1.5min, so that a large amount of VN is precipitated.

[0030] The cooling is controlled by the cooling bed...

Embodiment 2

[0035] First, during converter smelting, N element is added to control the main components of the steel in this example (referred to as Invention Steel B): [C]: 0.40%, [Si]: 0.23%, [Mn]: 0.71% , [V]: 0.20%, [N]: 0.0097%, and the rest are iron and impurities. The addition of N elements can be realized by the following method: connect N to the bottom blowing argon (Ar) gas pipeline of the refining furnace ladle 2 Gas valve, blowing N into the molten steel during the refining process 2 gas.

[0036] Secondly, the size of the continuous casting slab smelted in the converter: 150×150mm, the heating temperature of the casting slab is in the range of 1105-1125°C for 35 minutes, and the Φ25mm round steel is rolled.

[0037] Utilizing the sealed state of the rolling raceway, the rolled piece is kept in the range of 830-839°C for 1.8 minutes, so that a large amount of VN is precipitated.

[0038] The cooling is controlled by the cooling bed, the cooling rate is 0.95°C / s, and it is bu...

Embodiment 3

[0043] First, during electric furnace smelting, N element is added, so that the main components of the steel in this example (denoted as Invention Steel C) are controlled as follows: [C]: 0.50%, [Si]: 0.25%, [Mn]: 0.62% , [V]: 0.16%, [N]: 0.0120%, and the rest are iron and impurities. The addition of N elements can be realized by the following method: connect N to the bottom blowing argon (Ar) gas pipeline of the refining furnace ladle 2 Gas valve, blowing N into the molten steel during the refining process 2 gas.

[0044] Secondly, the size of the continuous casting slab smelted in the electric furnace: 240×240mm, the heating temperature of the casting slab is in the range of 1170-1195°C for 75 minutes, and the Φ70mm round steel is rolled.

[0045] Utilizing the sealed state of the rolling raceway, the rolled piece is allowed to stay in the range of 845-855°C for 1.2min, so that a large amount of VN is precipitated.

[0046] The cooling is controlled by the cooling bed, th...

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Abstract

The invention discloses a method for enhancing strength and toughness of medium-carbon V steel, which comprises the following steps: 1) in the smelting process, adding N to control [C], [V] and [N] in the steel; 2) heating the smelted continuous casting billet until the crystalline VN compound is dissolved back to austenite, and rolling into round steel; 3) keeping the temperature within the maximum precipitation peak value range to precipitate abundant VN particles; and 4) controlling the subsequent cooling rate of the round steel within a certain range so that the particle size of more than 80% of VN precipitated phase in the steel is 20-100nm, thereby obtaining the medium-carbon V steel with higher strength and toughness. By using the influence of the N element on different aspects of steel performance, the minor element component system is designed without modifying the production equipment or greatly adjusting the technique; and the yield strength of the medium-carbon V steel can be enhanced by 80-170 MPa, the ductility and fracture toughness of the steel are well improved, the percentage elongation after fracture A is enhanced by 3-5%, and the ballistic work Aku2 is enhanced by 10-50J.

Description

technical field [0001] The invention relates to a production method of medium-carbon V-steel, in particular to a method for improving the strength and toughness of medium-carbon V-steel, and belongs to the technical field of steel processing. Background technique [0002] Medium carbon V (vanadium) steel mainly refers to 35MnV, 40CrV, 50CrVA, 40MnVB, SAE6140 (ASTM A355 standard), EN51CrV4 (EN10083 / 1 standard) and other steel types, which are mostly used in the manufacture of auto parts, mechanical components, springs, tools, etc. The field is very extensive, and its characteristics are: ①C content in steel is 0.32-0.65%; ②V content in steel is 0.10-0.30%, especially concentrated in 0.10-0.20%; ③Steel needs to be quenched, tempered and tempered before application Therefore, the requirements for the strength and toughness of steel are very strict. [0003] The strength and toughness of these steels are mainly achieved by means of solid-solution strengthening of alloying eleme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/04
Inventor 陈庆丰许竹桃陈华强汪菊华余爱华张欢张青山黄海玲黄红明李献忠李伟万升
Owner WUHAN IRON & STEEL GRP ECHENG IRON & STEEL CO LTD
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