High-strength steel plate with low welding crack sensitivity of 420mpa level and manufacturing method thereof

Abstract

The invention discloses a 420MPa level low welding crack sensitivity high-strength steel plate and a manufacturing method thereof. The 420MPa level low welding crack sensitivity high-strength steel plate comprises 0.05%-0.1% of C, 0.10%-0.3% of Si, 1.40%-1.7% of Mn, smaller than or equal to 0.02% of P, smaller than or equal to 0.005% of S, 0.03%-0.06% of Nb, 0.03%-0.05% of V, 0.008%-0.02% of Ti, 0.15%-0.5% of Ni, 0.15%-0.5% of Cu, 0.08%-0.3% of Mo, 0.15%-0.35% of Cr+Mo, smaller than or equal to 0.005% of Ca, smaller than or equal to 3 of Cu / Ni, 0.015%-0.045% of Als, 0.5-2 of Ca / S, smaller thanor equal to 0.0005% of B, 0.17%-0.21% of Pcm, and the balance Fe. The yield strength of the steel plate is larger than or equal to 420 Mpa, and the transverse ballistic work is larger than or equal to 100 J.

Description

technical field [0001] The invention belongs to the technical field of medium-thick steel plate production. It specifically relates to a production method of high-strength steel plates with a yield strength of not less than 420Mpa and low welding crack sensitivity by using a normalizing + tempering process, especially suitable for steel plates for pressure vessels requiring a stable structure of 420MPa and high toughness requirements. Production of steel plates for pipelines. Background technique [0002] In the past 20 years, with the rapid development of my country's national economy and the rapid improvement of the technical capabilities of the iron and steel metallurgy industry, my country's steel demand and steel grades in the energy field have also gradually increased. Among them, the demand and research and development of steel plates with high strength and excellent welding performance have also been the focus of industry attention for a long time. [0003] Steel p...

AI Technical Summary

Problems solved by technology

In the field of pipelines, the corresponding steel grade is X60N, which belongs to the highest level of normalized delivery in all common pipeline standards. The steel plate delivered in the normalized state has more advantages than the common TMCP state in terms of structure and performance uniformity. However, the low-carbon design of pipeline steel is prone to insufficient strength after normalizing, and there is a situation of non-equilibrium structure

[0005] According to the current data, Publication No. CN107034414A proposes a high-strength normalizing container steel with a yield strength of 415Mpa and a heat treatment method. Low-cost ultra-low temperature normalized pipeline steel and its production method, the steel plate produced has low cost and excellent welding performance, but the strength level is only 345Mpa

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