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Production method of hydrogen induced cracking resistant steel

A technology of anti-hydrogen-induced cracking and production methods, applied in the manufacture of converters, etc., can solve the problem of reducing the hydrogen-induced cracking resistance of hydrogen-induced cracking steel, reducing the strength of hydrogen-induced cracking-resistant steel, ductility impact toughness and other mechanical properties, sulfur content Low compliance rate and other issues, to achieve the effect of low-cost production

Inactive Publication Date: 2015-07-08
SHANDONG IRON & STEEL CO LTD
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AI Technical Summary

Problems solved by technology

The reason why hydrogen-induced cracking-resistant steel has such a high requirement for sulfur content in molten steel is mainly because higher sulfur content will have two major effects on hydrogen-induced cracking-resistant steel: (1) Significantly reduce the hydrogen-induced cracking resistance Mechanical properties such as strength, ductility, and impact toughness in the transverse direction of the steel; (2) Significantly reduce the ability of the hydrogen-induced cracking-resistant steel to resist hydrogen-induced cracking (HIC)
[0003] At present, domestic and foreign petroleum refining and chemical enterprises continue to increase the demand for anti-hydrogen-induced cracking steel. However, the production of hydrogen-induced cracking-resistant steel using existing processes has low production efficiency, high cost, unstable control, and low compliance rate of sulfur content. Meet the large demand of the market
It is very difficult for industrial production to achieve such low hydrogen and sulfur content control requirements and mass production. The control of hydrogen elements is completed by the RH vacuum refining furnace, but the control of sulfur elements requires the help of KR processing equipment, converters and The joint realization of LF refining equipment involves many processes and production equipment, and the control is difficult. In the past, the best level of stable control of sulfur content in molten steel was around 0.0050%. To achieve sulfur content within 0.0020% and hydrogen content within 0.0002%, both meet Its quality requirements, without increasing the cost, it is imperative to improve the existing hydrogen-induced cracking resistance steel production process

Method used

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  • Production method of hydrogen induced cracking resistant steel

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Effect test

Embodiment 1

[0040] Production method of Q345R hydrogen-induced cracking resistant steel:

[0041] 1) Hot metal pretreatment: Desulfurize the hot metal with KR hot metal desulfurization technology, pour the ladle slag into the hot metal tank before tapping, use the strong reducibility of the ladle slag to desulfurize the hot metal, and adjust the insertion depth and speed of the stirring head to 1400mm~1450mm and 90 rpm to 96 rpm, until the weight percentage of sulfur in the molten iron is within 0.005%;

[0042] 2) Converter blowing: steel scrap is used as the cold material of the converter, the weight percentage of P in the scrap steel is less than 0.1%, the weight percentage of S is less than 0.08%, and the concentration of [O] in the steel in the second blowing stage is reduced to 0.050%-0.070 %, lime and dolomite are used as coolants in the later stage of blowing, and red ore powder chilled balls are prohibited to be added, and the basicity of the final slag is increased to 2.7-3.0, a...

Embodiment 2

[0049] Production method of Q245R hydrogen-induced cracking resistant steel:

[0050] 1) Hot metal pretreatment: Desulfurize the hot metal with KR hot metal desulfurization technology, pour the ladle slag into the hot metal tank before tapping, use the strong reducing property of the ladle slag to desulfurize the hot metal, and adjust the insertion depth and speed of the stirring head to 1460mm~1500mm and 95 rpm to 100 rpm, until the weight percentage of sulfur in molten iron is within 0.005%;

[0051] 2) Converter blowing: steel scrap is used as the cold material of the converter, the weight percentage of P in the scrap steel is less than 0.1%, the weight percentage of S is less than 0.08%, and the [O] concentration in the steel in the second blowing stage is reduced to 0.065%-0.080 %, lime and dolomite are used as coolants in the later stage of blowing, and red ore powder chilled balls are prohibited to be added, and the basicity of the final slag is increased to 3.1-3.5, an...

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Abstract

The invention discloses a production method of hydrogen induced cracking resisting steel. The production method comprises the steps of molten iron pretreatment, converter blowing, CAS slag washing, LF furnace refining, RH furnace dehydrogenation and continuous casting. By adopting a refining slag synthetic technology, the initial refining slag alkalinity is controlled to be about 4.0, wherein the weight percentage of FeO and MnO is less than 1%, the weight percentage of Al2O3 is more than or equal to 20%, and the weight percentage of CaO is more than or equal to 45%; a large-flow argon blowing stirring technology is adopted; a temperature control technology is adopted, the temperature of molten steel before LF furnace slag washing is 1550-1570 DEG C, and the temperature of the slag washing process is 1580-1600 DEG C to ensure that the weight percentage of sulfur is effectively controlled within 0.0020%, the average weight percentage of sulfur is 0.0012%, and the lowest weight percentage of sulfur is 0.0003%; and the desulfurization rate of an LF refining furnace is improved from 60.53% to 83.66%, the furnace treatment with the unqualified sulfur content is reduced from 20% to 0, the consumption of desulfurization slag forming materials is reduced by 3.2kg / t steel, and the system desulfurization time is averagely shortened by 5-6 minutes. By adopting the production method, on the premise that the quality is ensured, large-batch, stable and low-cost production of the hydrogen induced cracking resisting steel is realized.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a production method of hydrogen-induced crack-resistant steel. Background technique [0002] Hydrogen-induced cracking-resistant steel belongs to high-end pipeline steel, which is mainly used in pipeline materials in petroleum, refining and chemical industries. This type of steel has very strict requirements on the content of hydrogen and sulfur elements: the content of hydrogen element in steel is required to be below 0.0002%, and the content of sulfur element to be below 0.0020%. The reason why hydrogen-induced cracking-resistant steel has such a high requirement for sulfur content in molten steel is mainly because higher sulfur content will have two major effects on hydrogen-induced cracking-resistant steel: (1) Significantly reduce the hydrogen-induced cracking resistance The strength, ductility, impact toughness and other mechanical properties of the steel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/28C21C5/36C21C7/06C21C7/10
Inventor 刁承民丁中刘飞李彩霞刘国孙争取杜海生孔雅王衔玉孙秀菊
Owner SHANDONG IRON & STEEL CO LTD
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