Manufacturing method of marine 5Ni steel plate with low remanence and excellent surface quality

Abstract

The invention relates to a manufacturing method of a marine 5Ni steel plate with low remanence and excellent surface quality. The technological process is converter smelting -> LF refining -> RH highvacuum degassing -> Ca treatment -> continuous casting -> casting blank slow cooling treatment -> casting blank surface cleaning -> heating -> rolling -> quenching twice -> tempering. According to component design, low carbon, low silicon and 5% of Ni are adopted, and V and Nb are added, so that hardenability is improved, low-temperature toughness is improved, austenitic amorphous starting temperature is raised, the steel plate can be subjected to high-temperature rolling and high-temperature quenching, then the shape of the steel plate is remarkably improved, and the steel plate is suitable for production of thin specification products. According to the manufacturing method, optimization is performed from the perspectives of element design, technology control, base material organization,center segregation, quenching and tempering temperature and time and the like, and therefore it is guaranteed that the steel plate has good ductility, -130 DEG C low-temperature impact toughness, excellent surface quality and low remanence while high strength of the 5Ni steel plate is realized.

Description

technical field [0001] The invention relates to a manufacturing method of a marine steel plate, in particular to a manufacturing method of a marine 5Ni steel plate. Background technique [0002] In addition to pipeline transportation, liquefied petroleum gas (LPG) is mainly transported by sea. Ships are used to store and transport LPG, and transport ships used to transport LPG and liquefied ethylene (LEG) obtained through petroleum cracking and liquefaction are usually It is constructed of 5Ni steel with high strength, good low temperature toughness and high elongation. 5Ni steel means that the Ni content in the steel reaches about 5%. Due to the high Ni content, high surface quality requirements and low impurity participation requirements of 5Ni steel, higher requirements are put forward for smelting, rolling, heat treatment and other production processes. In addition, low remanence is also an important factor restricting the mass production of 5Ni steel. [0003] The pa...

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Problems solved by technology

Billet opening has a good effect on the uniformity of the steel plate structure and properties, but it also significantly increases the production cost and prolongs the production process.

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