Alloying hot-dip galvanized steel of which tensile strength is greater than or equal to 780MPa and production method of alloying hot-dip galvanized plate

Abstract

The invention relates to an alloying hot-dip galvanized plate of which the tensile strength is greater than or equal to 780MPa and a production method of the alloying hot-dip galvanized plate. The alloying hot-dip galvanized plate comprises the following components in percentage by weight (wt%) of: 0.080-0.100% of C, 1.85-1.95% of Mn, 0.010-0.020% of Si, 0.35-0.40% of Cr, 0.20-0.30% of Mo, less than or equal to 0.01% of P, less than or equal to 0.006% of S, 0.04-0.06% of Al, 0.04-0.07% of Ti, and less than or equal to 0.005% of N. The production method comprises the following production steps of performing conventional hot rolling, performing cool, performing crimping, performing acid pickling, performing cold rolling, and performing continuous annealing; performing mist cooling until the temperature achieves hot-dip galvanizing temperature; performing continuous hot-dip galvanizing; performing alloying; performing cooling by an air knife; and performing after working procedure treatment. According to the alloying hot-dip galvanized plate disclosed by the invention, under the conditions that the tensile strength is greater than or equal to 780Mpa, the yield strength is greater than or equal to 480MPa, the elongation rate is greater than or equal to 17%,and n value is greater than or equal to 0.13 are guaranteed, through reducing the additive amount of Si, the additive amount of Mn, the additive amount of Cr and the additive amount of Mo, the surface of the steel plate has good platability and is provided with a good plating structure; and the usage amount of the alloy is also reduced by 5% or above.

Description

technical field [0001] The invention relates to a steel for automobiles and a production method, in particular to an alloyed hot-dip galvanized steel with a tensile strength ≥ 780 MPa and a production method. Background technique [0002] At present, the development of high-end automotive steel towards high-strength steel has become an inevitable trend. As one of them, dual-phase steel has the advantages of low yield strength, high tensile strength and good plasticity, so it has become the first choice for high-end automotive steel, and its usage is expected to account for more than 75% of advanced high-strength steel for automotive . Compared with ordinary cold-rolled steel, galvanized dual-phase steel also has excellent corrosion resistance, which ensures that high-end cars have good corrosion resistance and perforation ability. Currently, it is mainly used for structural parts and reinforcements of high-end cars. Zinc duplex steel can also be used in automotive panels. ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the deficiencies of poor platability and substandard mechanical properties of high-strength steel existing in the prior art, and provide a method that ensures tensile strength ≥ 780Mpa, yield strength ≥ 480MPa, and elongation ≥ 17%. Make the n value ≥ 0.13, reduce the addition of Mn, Si and Cr, so that the surface of the steel plate has good platability and coating structural properties, and also reduce the amount of alloy, and use an alloy with a tensile strength ≥ 780MPa of not less than 5%. Hot-dip galvanized steel and production method

Images