800MPa-grade high heat input welding resistant pressure vessel steel and preparation method thereof

Abstract

The invention relates to 800MPa-grade high heat input welding resistant pressure vessel steel and a preparation method thereof. The steel comprises the following elements in percentage by mass: 0.05%-0.10% of C, less than or equal to 0.10% of Si, 1.50%-2.00% of Mn, less than or equal to 0.008% of P, less than or equal to 0.002% of S, 0.10%-0.50% of Cu, 0.10%-0.60% of Mo, 1.00%-2.00% of Ni, 0.010%-0.050% of Nb, 0.015%-0.030% of Ti, 0.001%-0.002% of B, 0.010%-0.030% of Ce, 0.015%-0.045% of Als, 0.0050%-0.0080% of N, 0.002%-0.006% of Ca and the balance Fe and inevitable impurities, in addition, Ti/N is more than or equal to 3 and less than or equal to 4, Ca/S is more than or equal to 2, fB is more than or equal to 1.4 and less than or equal to 1.6, fB=1+1.5(0.9-Ceq), Pcm is less than or equal to 0.25,Ceq is less than or equal to 0.57, and Psr is less than or equal to 0. The steel is high in strength and toughness, is suitable for submerged arc welding, gas shielded welding, electrogas welding, electroslag welding and other welding with different linear energy inputs, and can be used for manufacturing various large petrochemical engineering pressure-bearing equipment.

Description

technical field [0001] The invention relates to the technical field of low-alloy high-strength steel manufacturing, in particular to an 800MPa-class steel for welding pressure vessels resistant to large heat input and a preparation method thereof. Background technique [0002] Before the present invention was proposed, there were some similar technical products related to the field of high heat input welding pressure vessel manufacturing, but the strength was relatively low. The steel grade 12MnNiVR in GB / T 19189-2011 belongs to the large energy input welded pressure vessel steel, but requires off-line quenching and tempering treatment, and its tensile strength is only 610MPa. [0003] The Chinese patent application with the application number 200710039741.0 provides a "high-strength and high-toughness steel plate welded with low yield ratio and large heat input and its manufacturing method". The chemical composition of the steel is C: 0.025% to 0.055%. Si≤0.20%, Mn: 1.40%~...

AI Technical Summary

Problems solved by technology

In order to improve production efficiency, the manufacturing process of large marine storage tanks in my country requires high-energy welding, but the welding line energy of 800MPa steel grades generally does not exceed 50kJ / cm, which cannot meet the requirements of the rapid development of the industry.

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