High ductility negative 110 degree low-temperature steel and manufacturing method thereof

Abstract

The invention relates to high toughness -110 DEG C low temperature steel and a method for manufacturing the low temperature steel, the steel is composed of components with following weight percent: C 0.02-0.12, Si 0.10-0.35, Mn 0.30-0.80, P<=0.015, S<=0.010, Ni 3.20-3.80, Ti 0.005-0.05a and Al 0.005-0.10, the low temperature steel also comprises two or more than two of Nb<=0.050, V<=0.10, Cu<=2.0, Mo<=0.50, Zr<=0.040 and RE<=0.020, and allowance is Fe. The method for manufacturing comprises: coating anti-oxidation coating on the surface of casting billets and controlling proper technological parameter such as the initial rolling temperature of steel, the controlled rolling accumulated reduction rate, each operation secondary reduction rate for last three operations, the finish rolling temperature, the normalizing heat preservation temperature, the heat preservation time, the tempering heat preservation temperature and the like. The method has the advantages of pure steel quality, stable organization, stable and excenlent-110DEG C low temperature toughness, simple technique and low cost, and is beneficial for extending and applying.

Description

technical field [0001] The present invention relates to a steel and its manufacturing method. Background technique [0002] Prior to the present invention, Chinese Patent Publication Nos. CN98807689.6 and CN96190145.4 respectively disclosed "weldable ultra-high-strength steel with excellent ultra-low temperature toughness" and "high-strength trunk pipe steel with low yield ratio and excellent low-temperature toughness" , the Ni content of the involved steel ranges from 0.2 to 1.0%, and the low temperature impact test temperature is -40°C. Another example is the Japanese patent JP592643201, which discloses "a production method of high-strength steel plate for low temperature use". By performing hot rolling, cooling and heat treatment on low-alloy steel containing 1.0-4.0% Ni, excellent low-temperature toughness at -40°C is obtained. . The temperature of the low-temperature impact test of the above-mentioned patents is only -40°C. Contents of the invention [0003] The pu...

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The low temperature impact test temperature of the above patents is only -40°C

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