Method for reducing Cr and Mo steel mill bar frame-shaped segregation

A steel rolling and frame-shaped technology, which is applied in the field of frame-shaped segregation of Mo steel rolled materials and reduces Cr, can solve the problems of not accurately giving specific parameters or specific research methods for frame-shaped segregation control, and achieves the reduction of macroscopic segregation. Effects of frame segregation, reduction of segregation and simplification of annealing process

Inactive Publication Date: 2012-09-19
NORTHEASTERN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

To sum up, there are no public research reports on the frame segregation control technology of Cr and Mo steel products, and there are no specific parameters or specific research methods for the frame segregation control in the production process of Cr and Mo steels. public report

Method used

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  • Method for reducing Cr and Mo steel mill bar frame-shaped segregation
  • Method for reducing Cr and Mo steel mill bar frame-shaped segregation
  • Method for reducing Cr and Mo steel mill bar frame-shaped segregation

Examples

Experimental program
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Effect test

Embodiment 1

[0032]The Φ15mm wire rod for high-strength bolts is produced by 325mm×280mm bloom continuous casting-billet opening-wire rolling process. The chemical composition of Cr and Mo steel used is: C: 0.33%, Si: 0.35%, Mn 0.90%, S: ≤0.030%, P ≤0.030%, Cr: 1.20%, Ni: ≤0.25%, Cu: ≤0.030, Mo: 0.30%, the balance is iron, a steel rolling frame with reduced Cr and Mo The method of shape segregation is carried out according to the following steps:

[0033] (1) The Cr and Mo steel billets with the above components are continuously cast. During the continuous casting process, the parameters of the billet continuous casting machine are set as follows: electromagnetic stirring intensity 200A, frequency 2.4Hz, total water volume in the secondary cooling zone 102.6L / min, wide surface cooling The total amount of water is controlled at 54.15L / min; the total amount of narrow surface cooling water is controlled at 48.45L / min; the specific water volume is 0.225L / kg, the degree of superheat is 20°C, an...

Embodiment 2

[0040] 325mm×280mm bloom continuous casting-blooming-wire rolling process is used to produce Φ8mm wire rod for high-strength bolts. The chemical composition of Cr and Mo steel used is: C: 0.38%, Si: 0.2%, Mn : 0.70%, S: ≤0.030%, P ≤0.030%, Cr: 0.90%, Ni: ≤0.25%, Cu: ≤0.030, Mo: 0.15%, the balance is iron, a kind of rolled steel with reduced Cr and Mo The method of frame segregation is carried out according to the following steps:

[0041] (1) Carry out continuous casting of Cr and Mo steel billets. During the continuous casting process, the parameters of the billet continuous casting machine are set as follows: electromagnetic stirring intensity 150A, frequency 2Hz, total water volume in the secondary cooling zone 107.3L / min, of which the total amount of cooling water in the inner arc Controlled at 27.55L / min, the total amount of outer arc cooling water is controlled at 29.05L / min, the total amount of narrow surface cooling water is controlled at 50.7L / min; min;

[0042] (2)...

Embodiment 3

[0046] The Φ11mm wire rod for high-strength bolts is produced by using 325mm×280mm bloom continuous casting-billet opening-wire rolling process. The chemical composition of Cr and Mo steel used is: C: 0.35%, Si: 0.15%, Mn : 0.60%, S: ≤0.030%, P ≤0.030%, Cr: 1.0%, Ni: ≤0.25%, Cu: ≤0.030, Mo: 0.2%, the balance is iron, a kind of rolled steel with reduced Cr and Mo The method of frame segregation is carried out according to the following steps:

[0047] (1) Carry out continuous casting of Cr and Mo steel billets. During the continuous casting process, the parameters of the billet continuous casting machine are set as follows: electromagnetic stirring intensity 250A, frequency 2.5Hz, total water volume in the secondary cooling zone 97.9L / min, total cooling water volume in the wide surface Control at 51.7L / min; the total amount of cooling water on the narrow surface is controlled at 46.2L / min; the specific water volume is 0.236L / kg, the degree of superheat is 25°C, and the casting ...

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Abstract

The invention provides a method for reducing Cr and Mo steel mill bar frame-shaped segregation, belonging to the technical field of metallurgy. The method comprises the following steps of: carrying out continuous casting to a Cr and Mo billet; controlling the electromagnetic stirring strength and frequency, total secondary cooling area water quantity, specific water flow, overheating and drawing speed; further carrying out cogging, wherein the heating temperature ranges from 1220 DEG C to 1280 DEG C and the heating time is 6-8 h; rolling, wherein the rough rolling temperature is 1080 DEG C, the finish rolling is 95 DEG C and the spinning temperature is 860 DEG C; cooling to 530 DEG C to 480 DEG C rapidly at cooling speed more than 5 DEG C / S after the rolling; and keeping the temperature to more or less than 300 DEG C to 350 DEG C and carrying out coiling so as to obtain a Cr and Mo steel mill bar without the frame-shaped segregation. If the phenomenon of slight tissue unevenness exists, a simplification annealing process for eliminating the tissue unevenness is carried out. With the method provided by the invention, the frame-shaped segregation of the Cr and Mo steel mill bar is eliminated; the frame-shaped segregation under cool acid reaches or approximates to 0 level; and the frame-shaped segregation under hot acid is controlled to be not more than 1.0 level.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for reducing the frame segregation of rolled Cr and Mo steel products. Background technique [0002] Adding metal element Cr to steel can significantly improve the strength, hardness and wear resistance of steel, and adding metal element Mo can refine the grain of steel, improve hardenability and thermal strength, and maintain sufficient strength at high temperatures and the effect of creep resistance. Therefore, steel containing Cr and Mo elements has better hardenability, low temperature impact toughness, stronger fatigue strength and impact resistance. It is generally used to produce high-end steel products such as tools, molds, gears, and bearings. For example, 35CrMo, 42CrMo, etc. can be used to produce 12.9 high-strength bolts for automobile engines. Since the engine cylinder head and connecting rod bolts are subjected to high-frequency alternatin...

Claims

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Application Information

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IPC IPC(8): B22D11/18B21B37/74
Inventor 朱苗勇徐东祭程唐正友罗森田新中刘振民钟保军张素萍刘桂生
Owner NORTHEASTERN UNIV
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