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‑195°C ultra-low temperature seamless steel pipe and its preparation method

A seamless steel pipe and ultra-low temperature technology, applied in the field of seamless steel pipes, can solve the problems of limited use and achieve the effect of broad application prospects

Active Publication Date: 2017-08-29
PANGANG GROUP CHENGDU STEEL & VANADIUM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention overcomes the deficiencies of the prior art, and provides a -195°C ultra-low temperature seamless steel pipe and its preparation method, in order to solve the problem of the existing low temperature seamless steel pipe in liquefied petroleum gas, liquid ammonia, liquid oxygen, and liquid nitrogen. Issues with limited use in other fields

Method used

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  • ‑195°C ultra-low temperature seamless steel pipe and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] (1) Smelting tube billet

[0026] Raw materials are smelted in an ultra-high power electric arc furnace to obtain primary molten steel, and then the primary molten steel is subjected to LF refining to improve the purity of the steel, and then the molten steel is subjected to VD vacuum treatment to further improve the purity of the steel, and then the round billet is used The continuous casting machine casts continuous casting round billets with a specification of Φ200-430 mm to obtain tube billets, and its chemical composition is shown in Table 1.

[0027] In the process of smelting, refining outside the furnace, and casting, the operation is strictly in accordance with the specifications to make the chemical composition of the steel uniform, so as to ensure the mechanical properties and low-temperature impact toughness of the steel pipe. The T[O] content of the tube blank: 10-20ppm, the total amount of stable non-metallic inclusions in the tube blank: 30-50ppm.

[002...

Embodiment 2

[0033] (1) Smelting tube billet

[0034] Raw materials are smelted in an ultra-high power electric arc furnace to obtain primary molten steel, and then the primary molten steel is subjected to LF refining to improve the purity of the steel, and then the molten steel is subjected to VD vacuum treatment to further improve the purity of the steel, and then the round billet is used The continuous casting machine casts continuous casting round billets with a specification of Φ200-430 mm to obtain tube billets, and its chemical composition is shown in Table 1.

[0035] In the process of smelting, refining outside the furnace, and casting, the operation is strictly in accordance with the specifications to make the chemical composition of the steel uniform, so as to ensure the mechanical properties and low-temperature impact toughness of the steel pipe. The T[O] content of the tube blank: 10-20ppm, the total amount of stable non-metallic inclusions in the tube blank: 30-50ppm.

[003...

Embodiment 3

[0041] (1) Smelting tube billet

[0042]Raw materials are smelted in an ultra-high power electric arc furnace to obtain primary molten steel, and then the primary molten steel is subjected to LF refining to improve the purity of the steel, and then the molten steel is subjected to VD vacuum treatment to further improve the purity of the steel, and then the round billet is used The continuous casting machine casts continuous casting round billets with a specification of Φ200-430 mm to obtain tube billets, and its chemical composition is shown in Table 1.

[0043] In the process of smelting, refining outside the furnace, and casting, the operation is strictly in accordance with the specifications to make the chemical composition of the steel uniform, so as to ensure the mechanical properties and low-temperature impact toughness of the steel pipe. The T[O] content of the tube blank: 10-20ppm, the total amount of stable non-metallic inclusions in the tube blank: 30-50ppm.

[0044...

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PUM

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Abstract

The invention discloses a seamless steel tube used at an ultra-low temperature of -195 DEG C and a preparing method of the seamless steel tube. The seamless steel tube is prepared from, by weight, 0.05%-0.08% of C, 0.16%-0.27% of Si, 0.75%-0.88% of Mn, 0%-0.006% of P, 0%-0.003% of S, 8.5%-8.9% of Ni, 0.02%-0.04% of Al, 0%-0.02% of Mo, Fe and the like. The preparing method of the seamless steel tube comprises the steps that firstly, a tube blank is smelted; secondly, rolling is conducted, and the temperature of an annular furnace in the rolling process needs to guarantee that the temperature of the tube blank discharged out of the furnace is 1245-1265 DEG C; and thirdly, heat treatment is conducted on the steel tube by conducting normalizing and tempering twice, and the tempering temperature is 570-590 DEG C. The mechanical property and the impact toughness at the low temperature of -195 DEG C of the seamless steel tube used at the ultra-low temperature completely meet the technical requirements of the seamless steel tube used at the ultra-low temperature of -195 DEG C, the impact value at the low temperature of -195 DEG C reaches over 165 J, and the transverse expansion value at the low temperature of -195 DEG C reaches over 1.74 mm.

Description

technical field [0001] Embodiments of the present invention relate to the field of seamless steel pipes, and more specifically, embodiments of the present invention relate to a seamless steel pipe for -195°C ultra-low temperature and a preparation method thereof. Background technique [0002] With the rapid development of my country's economy, domestic petroleum, chemical and other energy industries need a large amount of low-temperature steel to manufacture various production and storage equipment for liquefied petroleum gas, liquid ammonia, liquid oxygen, and liquid nitrogen. Due to the flammability and ultra-low temperature of liquefied natural gas, compared with ordinary low-temperature pressure vessels, steel pipes for storage and transportation must have comprehensive characteristics such as strength, thermal stress and strain, welding performance and corrosion resistance, and the material is also required to be resistant to brittle crack propagation It has extremely s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/08C22C38/12C22C38/14C22C33/04C21D8/10C21D1/28
CPCC21D1/28C21D8/105C22C33/04C22C38/02C22C38/04C22C38/06C22C38/08C22C38/12C22C38/14
Inventor 胡茂会郭元蓉吴红涂露寒
Owner PANGANG GROUP CHENGDU STEEL & VANADIUM