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A method to reduce segregation of 40cr cold heading steel wire rod ingot shape

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

Active Publication Date: 2018-01-05
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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  • A method to reduce segregation of 40cr cold heading steel wire rod ingot shape
  • A method to reduce segregation of 40cr cold heading steel wire rod ingot shape

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] According to the chemical composition of 40Cr cold heading steel, molten steel was poured into a bloom with a section size of 280×380 mm. The superheated degree of molten steel was 26 °C, the casting speed was 0.75 m / min, the electromagnetic stirring voltage of the mold was 100 V, and the current intensity was 150 A, the frequency is 2 Hz; the electromagnetic stirring voltage at the end of solidification is 300 V, the current intensity is 450 A, and the frequency is 5 Hz.

[0024] The bloom is heated and rolled into a 150*150 mm continuous rolling slab, and the continuous rolling slab is inspected for flaws, and the defects such as cracks on the surface are repaired to ensure that the continuous rolling slab has no defects on the surface.

[0025] Rolling:

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

[0027] (2) Control the rough rolling start tempera...

Embodiment 2

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

[0031] The bloom is heated and rolled into a 150*150 mm continuous rolling slab, and the continuous rolling slab is inspected for flaws, and the defects such as cracks on the surface are repaired to ensure that the continuous rolling slab has no defects on the surface.

[0032] Rolling:

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

[0034] (2) Control the rough rolling start t...

Embodiment 3

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

[0038] The bloom is heated and rolled into a 150*150 mm continuous rolling slab, and the continuous rolling slab is inspected for flaws, and the defects such as cracks on the surface are repaired to ensure that the continuous rolling slab has no defects on the surface.

[0039] Rolling:

[0040] (1) Heat the continuous rolling billet to 1030 °C, keep it warm for 110 minutes, and the temperature difference of the continuous rolling billet is 25 °C;

[0041] (2) Control the rough rolling start temperatur...

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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 in particular relates to a production method for reducing the influence of electromagnetic stirring on the internal quality of a 40Cr cold heading steel bloom and the segregation of a wire rod ingot shape. Background technique [0002] In the existing 40Cr cold heading steel bloom continuous casting process, the internal quality of the bloom is relatively good. However, after the continuous rolling and high-speed wire rolling process, there are serious ingot shape segregation defects in the cross section of the 40Cr cold heading steel wire rod, which affects the uniformity of plasticity, toughness, strength and hardness distribution of the wire rod, and makes the steel cold heading The performance and machinability deteriorate, which seriously affects the use of 40Cr cold heading steel wire rod in advanced automotive fasteners. [0003] Converter Publication No. CN102560253A...

Claims

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Application Information

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Patent Type & Authority Patents(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