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Method for relieving 40 Cr cold heading steel wire rod pattern segregation

A technology of ingot segregation and cold heading steel, applied in the field of metallurgical technology, can solve the problems such as the production method of 40Cr cold heading steel wire rod not involved, and achieve the effect of reducing ingot segregation defects

Active Publication Date: 2016-02-10
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this invention does not involve the production method of 40Cr cold heading steel wire rod

Method used

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  • Method for relieving 40 Cr cold heading steel wire rod pattern segregation
  • Method for relieving 40 Cr cold heading steel wire rod pattern segregation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] According to the chemical composition of 40Cr cold heading steel, the molten steel is poured into a bloom with a cross-sectional dimension of 280×380mm, the superheat of molten steel is 26℃, the drawing speed is 0.75m / min, the electromagnetic stirring voltage of the mold is 100V, and the current intensity is 150A. The frequency is 2Hz; the electromagnetic stirring voltage at the end of coagulation is 300V, the current intensity is 450A, and the frequency is 5Hz.

[0024] The blooms are heated and rolled into continuous-rolled billets with a size of 150*150mm, and the continuous-rolled billets are inspected for flaws, and the defects such as cracks on the surface are ground to ensure that the continuous-rolled billets are free of defects.

[0025] Rolling:

[0026] (1) Heat the continuous-rolled billet to 1040°C for 120 minutes, and the temperature difference of the continuous-rolled billet is 24°C;

[0027] (2) Control the rough rolling opening temperature to 960°C, the finishi...

Embodiment 2

[0030] According to the chemical composition of 40Cr cold heading steel, the smelting molten steel is poured into a bloom with a cross-sectional size of 280*380mm. The molten steel superheat is 28℃, the drawing speed is 0.80m / min, the electromagnetic stirring voltage of the mold is 120V, and the current intensity is 200A. The frequency is 4Hz; the electromagnetic stirring voltage at the end of solidification is 330V, the current intensity is 500A, and the frequency is 6Hz.

[0031] The blooms are heated and rolled into continuous-rolled billets with a size of 150*150mm, and the continuous-rolled billets are inspected for flaws, and the defects such as cracks on the surface are ground to ensure that the continuous-rolled billets are free of defects.

[0032] Rolling:

[0033] (1) Heat the continuous-rolled billet to 1060°C for 140 minutes, and the temperature difference of the continuous-rolled billet is 28°C;

[0034] (2) Control the rough rolling opening temperature at 945℃, the fini...

Embodiment 3

[0037] According to the chemical composition of 40Cr cold heading steel, smelt molten steel is poured into blooms with a cross-sectional size of 280*380mm, the superheat of molten steel is 27℃, the drawing speed is 0.78m / min, the electromagnetic stirring voltage of the mold is 135V, and the current intensity is 240A. The frequency is 5Hz; the electromagnetic stirring voltage at the end of solidification is 350V, the current intensity is 530A, and the frequency is 6Hz.

[0038] The blooms are heated and rolled into continuous-rolled billets with a size of 150*150mm, and the continuous-rolled billets are inspected for flaws, and the defects such as cracks on the surface are ground to ensure that the continuous-rolled billets are free of defects.

[0039] Rolling:

[0040] (1) Heat the continuous-rolled billet to 1030°C for 110 minutes with a temperature difference of 25°C;

[0041] (2) Control the rough rolling start-rolling temperature to 955℃, the finishing rolling inlet temperature t...

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Abstract

A method for relieving 40 Cr cold heading steel wire rod pattern segregation. The superheat degree of continuously-cast molten steel is smaller than or equal to 30 DEG C, the pull speed is 0.70-0.90 m / min, the electromagnetic stirring voltage of a crystallizer is 50-150 V, the current intensity is 100-300 A, and frequency is 1-6 Hz; the electromagnetic stirring voltage of the solidification tail end is 280-380 V, the current intensity is 400-600 A, and frequency is 4-8 Hz. The crack defect on the surface of a continuously-cast blank is ground; the cast blank is heated to 1010-1090 DEG C, and the temperature is preserved for 90-150 min. Initial rough rolling temperature is 930-980 DEG C, finish rolling inlet temperature is 880-950 DEG C, reducing and sizing inlet temperature is 850-920 DEG C, and spinning temperature is 850+ / -30 DEG C. The blank is cooled to 640-750 DEG C at the cooling speed of 6-12 DEG C / s and enters a cover, in-cover cooling speed is 0.2-1.0 DEG C / s, cover outgoing temperature is 460-630 DEG C, and cold bed air cooling is performed. By means of the method, the pattern segregation defect of a 40 Cr cold heading steel wire rod can be relieved, the current lever larger than or equal to 4 of pattern segregation is reduced to the lever smaller than or equal to 2, and the using requirement that high-strength and high-quality fastening pieces are produced can be met.

Description

Technical field [0001] The invention belongs to the technical field of metallurgical technology, and particularly relates to a production method for reducing the influence of electromagnetic stirring on the internal quality of 40Cr cold heading steel blooms and the segregation of wire rod ingots. Background technique [0002] In the existing 40Cr cold heading steel bloom continuous casting production process, the internal quality of the bloom is better. However, after continuous rolling and high-speed wire rolling, there are serious ingot segregation defects in the cross section of 40Cr cold-headed steel wire rod, which affects the uniformity of the plasticity, toughness, strength, and hardness distribution of the wire rod, and makes the steel cold-headed The performance and cutting performance deteriorate, which seriously affects the use of 40Cr cold heading steel wire rod in high-end automotive fasteners. [0003] The converter publication number CN102560253A discloses a method ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/115C21D8/06
Inventor 马立国郭大勇王秉喜高航张博罗建华车安袁野栾花冰
Owner ANGANG STEEL CO LTD