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Ultrapure smelting method of low-alloy high-strength steel

A low-alloy high-strength, pure technology, applied in the field of vacuum induction melting, can solve the problem of inability to achieve ultra-pure, and achieve the effect of improving hot working performance, improving service performance, and reducing ductile-brittle transition temperature

Active Publication Date: 2012-07-04
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an ultra-pure smelting method for low-alloy high-strength steel, which solves the problems in the prior art that cannot reach ultra-pure, and adopts this method to obtain oxygen content less than 10ppm, sulfur content less than 30ppm and nitrogen content Ultra-pure low-alloy high-strength steel less than 30ppm reduces the ductile-brittle transition temperature of steel and improves the processing performance of steel

Method used

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  • Ultrapure smelting method of low-alloy high-strength steel

Examples

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Embodiment 1

[0025] Use high-purity, thermodynamically stable CaO crucible to melt low-alloy high-strength steel. The melting process includes: charging → melting period → refining period → condensation → deoxidation, desulfurization period → pouring; among them, charging, melting period, pouring Using conventional techniques. The specific process is:

[0026] (1) 50kg CaO forming crucible for smelting crucible, CaO purity ≥ 98.5wt%;

[0027] (2) Alloy raw materials: According to the composition requirements, the constituent elements of steel such as industrial pure Fe, polysilicon, metal manganese and metal chromium, as well as deoxidizing and desulfurizing agents.

[0028] In this step, the deoxidizing and desulfurizing agent is a Si-Ca master alloy: Si: 25wt%, Ca 75wt%.

[0029] (3) Alloy charging: put the main raw materials Fe, Cr, and Si into the crucible, and put Mn and deoxidizing and desulfurizing agents into different compartments of the alloy feeding hopper;

[0030] (4) Alloy...

Embodiment 2

[0040] Use high-purity, thermodynamically stable CaO crucible to melt low-alloy high-strength steel. The melting process includes: charging → melting period → refining period → condensation → deoxidation, desulfurization period → pouring; among them, charging, melting period, pouring Using conventional techniques. The specific process is:

[0041] (1) 50kg CaO forming crucible for smelting crucible, CaO purity ≥ 98.5wt%;

[0042] (2) Alloy raw materials: According to the composition requirements, the constituent elements of steel such as industrial pure Fe, polysilicon, metal manganese and metal chromium, as well as deoxidizing and desulfurizing agents.

[0043] In this step, the deoxidizing and desulfurizing agents are Si-Ca master alloys: Si: 25wt%, Ca: 75wt%.

[0044] (3) Alloy charging: put the main raw materials Fe, Cr, and Si into the crucible, and put Mn and deoxidizing and desulfurizing agents into different compartments of the alloy feeding hopper;

[0045] (4) All...

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Abstract

The invention relates to the field of vacuum induction smelting, particularly an ultrapure smelting technical method of low-alloy high-strength steel. A CaO refractory material is utilized to form a crucible, and a vacuum induction smelting method is utilized to acquire the ultrapure low-alloy high-strength steel. In the melting period, carbon in the alloy raw material is utilized to carry out primary stage deoxidization and denitrification; in the refining period, the refining temperature is enhanced to reinforce the thermodynamicical and dynamic conditions for deoxidization and desulfurization, and effective deoxidization and desulfurization are carried out on the crucible wall part and the molten steel surface; and in the deoxidization and desulfurization period, strong deoxidizer and desulfurizer are added to carry out end deoxidization and desulfurization on the alloy so as to further lower the oxygen and sulfur contents in the alloy, so that the oxygen content is controlled below 10ppm, the sulfur content is controlled below 30ppm, and the nitrogen content is controlled below 30ppm. The invention can effectively improve the low-temperature impact toughness of the low-alloy high-strength steel, and further lower the tough-brittle transition temperature, thereby widening the application range of the low-alloy high-strength steel, enhancing the hot working properties of thealloy and acquiring the high-quality low-alloy high-strength steel.

Description

technical field [0001] The invention relates to the field of vacuum induction smelting, in particular to an ultra-pure smelting process for low-alloy high-strength steel. Background technique [0002] The carbon content of low-alloy high-strength steel is usually less than 0.25wt%, and it has a higher yield point σ than ordinary carbon structural steel s or yield strength σ 0.2 (290~780MPa) and yield ratio σ s / σ b (0.65 ~ 0.95), good cold and hot formability, good weldability, low cold brittleness tendency, notch and aging sensitivity, and good resistance to atmospheric and seawater corrosion. A higher content of Si, Mn, Ni, Cr and other alloying elements are added to the steel to improve the performance of a certain aspect, but the main means of obtaining high strength still depends on a higher carbon content. With the development of steel structure from riveting to welding, in order to improve the brittle fracture resistance of steel, it is gradually changing to the d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/10C21C7/06C21C7/064C22C33/04
Inventor 马颖澈张龙高明刘奎
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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