1180mpa grade high-strength hot-dip galvanized steel sheet with low hydrogen embrittlement crack sensitivity and preparation method

Abstract

The invention discloses a 1180 MPa-grade high-strength hot-dip galvanized steel plate with low hydrogen embrittlement crack sensitivity and a preparation method thereof. The method comprises the following components of 0.05%-0.8% of C, 1.00-5.00% of Mn, 0.70-1.60 % of Si, 0.01-1.00% of Al, 0.002-0.10% of Nb, 0.01-0.10 % of V, 0.001-0.1% of Ti, 0.01-0.5% of Mo, 0.002-0.005% of N, and the balance Feand inevitable impurities. The Nb, the V and the Ti micro-alloy elements are added to be combined with the C and the N, a middle roll temperature can be controlled to obtain a nano-scale cluster precipitate with tiny size, uniform distribution and large density, the strength of ferrite is remarkably enhanced, the strength difference of two matrix structures is reduced, more hydrogen traps are provided, the ferrite is reinforced, ferrite grains are refined, the stress concentration is relieved, and the hydrogen embrittlement sensitivity of the ferrite-martensite dual-phase steel is reduced.

Description

technical field [0001] The invention relates to the technical field of high-strength hot-rolled steel, in particular to a 1180MPa-level high-strength hot-dip galvanized steel sheet with low hydrogen embrittlement crack sensitivity and a preparation method. Background technique [0002] Iron and steel materials have the possibility of hydrogen infiltration during smelting, pickling, electroplating, welding and subsequent service, which leads to the risk of hydrogen embrittlement in advanced high-strength steel; coupled with the stress gradient during service, hydrogen is easy to migrate The enrichment of high-stress regions (such as phase boundaries, etc.) significantly increases the possibility of hydrogen embrittlement of load-bearing components (such as bolts, suspension springs, etc.) or load-bearing steel structures (such as pressure vessels, building structures, etc.). [0003] It is currently known that hydrogen embrittlement sensitivity increases sharply with the incr...

AI Technical Summary

Problems solved by technology

At present, most of the existing precipitation-strengthened steel plates on the market meet the requirements in mechanical properties, but for steel plates with a strength ≥ 1180 MPa, due to the low strength of ferrite, there is a large gap between the strength of the other structure (martensite or bainite) , and the content of martensite is relatively high, and the susceptibility to hydrogen embrittlement is high, which cannot meet the user's requirements

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