Low-nickel steel plate for pressure vessel at low temperature of -196 DEG C and production method thereof

Abstract

The invention discloses a low-nickel steel plate for a pressure vessel at low temperature of -196 DEG C and a production method thereof. The steel plate comprises the following components: C less than or equal to 0.04, Si less than or equal to 0.05, Mn between 1.60 and 2.50, P less than or equal to 0.005, S less than or equal to 0.003, Alt between 0.015 and 0.050, Ni between 6.00 and 8.00, Cu between 0.35 and 0.50, Cr between 0.55 and 1.00, N less than or equal to 0.004, at least one of Mo less than or equal to 0.35, Nb less than or equal to 0.05, Ti less than or equal to 0.025 and Ca less than or equal to 0.005, and Fe and inevitable impurities as the rest. During rolling, according to different thicknesses of steel plates, heat treatment processes of secondary normalizing and tempering, quenching and tempering, secondary quenching and tempering and the like are respectively performed. The prepared low-nickel steel plate has the advantage of low cost, a feasible production process is adopted, mass production operation of a low-temperature storage tank of LNG (Liquefied Natural Gas) is facilitated, and pressure vessel steel with good low-temperature toughness, excellent impact performance and strong welding performance is obtained.

Description

technical field [0001] The invention relates to an alloy steel for low-temperature pressure vessels and a production method thereof, in particular to a low-nickel steel plate for pressure vessels at a low temperature of -196°C and a production method thereof. Background technique [0002] With the diversification of global energy resources and the increasing emphasis on environmental protection, natural gas, as a clean energy, will occupy an increasing proportion in the future. The storage and transportation temperature of liquefied natural gas is below -162°C, which requires the materials used to store liquefied natural gas to have good low-temperature toughness, strength, and sufficient resistance to brittle cracking and crack arrest at ultra-low temperatures. [0003] At present, the materials used in the LNG storage and transportation equipment built in the world are mainly 9Ni steel with a Ni content of about 9%. Now, our country has carried out research work on Ni-bas...

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Problems solved by technology

Especially for the high cost of existing steel alloys, the alloy cost of this steel is relatively low

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