Hydrogen induced cracking-resistant cold-rolled hot-dip galvanized ultra-high-strength dual-phase steel and manufacturing method therefor

Abstract

A hydrogen induced cracking-resistant cold-rolled hot-dip galvanized ultra-high-strength dual-phase steel, comprising a substrate and a galvanized layer plated on the substrate, wherein the substrate contains Fe and inevitable impurity elements, and the substrate further contains the following chemical elements in percentage by mass: 0.1-0.18% of C, 2.2-3.0% of Mn, 0.2-0.6% of Si, 0.03-0.3% of Al, 0.01-0.1% of Nb, 0.01-0.1% of Ti, 0.04-0.2% of Mo, and 0.0005-0.003% of B. The matrixes of the microstructure of the substrate are ferrite and martensite, the microstructure of the substrate further comprises a carbide precipitation phase having a size less than 100 nm, and the carbide particles and the matrixes are in a coherent or semi-coherent state. A manufacturing method for the dual-phase steel comprises the following steps: (1) smelting and casting; (2) hot rolling; (3) acid pickling; (4) cold rolling; (5) hot-dip galvanizing and recrystallization annealing; and (6) cooling after galvanizing.

Dependencies are inferred from the claim text.