Ultra-low cost and SR brittle resisting low-temperature nickel steel plate and manufacturing method thereof

Abstract

The invention discloses an ultra-low cost and SR brittle resisting low-temperature nickel steel plate and a manufacturing method thereof. The ultra-low cost and SR brittle resisting low-temperature nickel steel plate is prepared from the following components in percentage by weight: 0.040-0.070% of C, no more than 0.15% of Si, 0.90-1.20% of Mn, no more than 0.012% of P, no more than 0.0020% of S,0.10-0.35% of Cu, 1.00-1.50% of Ni, 0.05-0.30% of Mo, 0.040-0.070% of Als, 0.007-0.014% of Ti, 0.008-0.025% of Nb, no more than 0.0040% of N, 0.0010-0.0035% of Ca, and the balance of Fe and unavoidable impurities. Under the condition of postwelding heat treatment, the yield strength of the steel plate is greater than or equal to 420 MPa, the tensile strength of the steel plate is greater than or equal to 530 Mpa, the minus 110 DEG C low-temperature impact work single value Akv of the steel plate is greater than or equal to 47 J, the Z-direction property of the steel plate is greater than or equal to 35%, and large heat input welding can be achieved; and the ultra-low cost and SR brittle resisting low-temperature nickel steel plate is particularly suitable for manufacturing large LPG low-temperature storage tanks, marine LPG low-temperature storage tanks, and large steel structures in ice sea and polar regions, and ultra-low cost and stable batch industrial production can be achieved.

Description

technical field [0001] The invention relates to high-strength low-carbon low-alloy steel, in particular to an ultra-low-cost, SR embrittlement-resistant low-temperature nickel steel plate and a manufacturing method thereof. ≥530MPa, -110°C low-temperature impact energy single value Akv≥47J, Z-direction performance ≥35%, and can be welded with high heat input; mainly used in the manufacture of LPG cryogenic storage tanks, marine cryogenic storage tanks, and steel structures in polar regions. Background technique [0002] As we all know, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, widely used in oil and gas pipelines, offshore platforms, shipbuilding, bridge structures, boiler containers, building structures, automobile industry, railway transportation and machinery manufacturing among. The properties of low-carbon (high-strength) low-alloy steel depend on its chemical composition and the process system of the manu...

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Problems solved by technology

[0007] Chinese Patent No. ZL201110071407.X discloses "low-temperature nickel steel with high tempering parameter SR embrittlement resistance and its manufacturing method", which adopts Ni content of about 3.0%, through normalizing + tempering (N+T) process, successfully An ultra-low temperature nickel steel with high tempering parameter SR embrittlement resistance and excellent weldability has been developed, but the impact temperature of the steel plate and the welding heat-affected zone can only reach -101°C, and the lower -110°C has not been involved; at the same time, the steel The Ni content in the medium reaches about 3.0%, and the two heat treatment processes of normalizing and tempering are adopted, the manufacturing cost is high, the manufacturing cycle is long, and the ability of the steel plate to withstand large heat input welding is also poor

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