Ultra high strength hot dip aluminized steel plate and manufacturing method thereof

Abstract

The invention provides an ultra high strength hot dip aluminized steel plate, which comprises the following components by weight: 0.20%-0.50% of C, 0.30%-2.00% of Si, 1.10-5.00% of Mn, less than or equal to 0.020% of P, less than or equal to 0.020% of S, 0.02%-1.50% of Al, less than or equal to 1.50% of Mo, also contains at least one of 0.20%-1.00% of Cr and 0.20%-3.00% of Ni, also contains at least one of less than or equal to 0.10% of Nb and less than or equal to 0.25% of Ti, also contains at least one of less than or equal to 0.004% of Ca and less than or equal to 0.004% of Mg, and the balance Fe and inevitable impurity elements. Specifically, Cr+Mo and Ni+Mo are not less than 0.6%, and Nb+Ti is not less than 0.06%. The method includes: heating the steel plate on a continuous hot dip aluminizing line to 750DEG C-850DEG C, preserving the temperature at 750 DEG C-840DEG C, performing cooling to hot dip aluminizing temperature by a cooling speed of not greater than 20DEG C / s, then conducting hot dip aluminizing, discharging the plating solution, and then performing cooling at a speed of not greater than 20DEG C / s. The steel plate greatly enhances the plasticity and toughness of hot dip aluminized steel plate after hot stamping forming, and improves the comprehensive performance of the product.

Description

technical field [0001] The invention belongs to the field of continuous production and manufacture of hot-dip aluminum-coated steel sheets, and in particular relates to an ultra-high-strength hot-dip aluminum-coated steel sheet and a manufacturing method thereof. Background technique [0002] For a long time, steel has been the basis of the automobile industry. Although the amount of aluminum alloy, magnesium alloy, plastic and composite materials in automobile manufacturing has been increasing, high-strength steel has high potential for weight reduction, high impact absorption energy, and high fatigue. The advantages of strength, high formability and low planar anisotropy have become the main lightweight materials for the automotive industry. The automobile industry in the 21st century to reduce fuel consumption and reduce CO 2 And exhaust emissions have become the main needs of the society. In order to adapt to this development trend, the steel industry has developed many...

AI Technical Summary

Problems solved by technology

[0004] The materials used in the existing thermoforming process are mainly B-containing steel, typical steel grades are 22MnB5, 30MnB, etc. Although the strength of the material has been greatly improved, the shaping of the steel plate has declined seriously, or There is basically no plasticity. In addition, the existence of B elements pollutes the grain boundary, reduces the cohesion of the grain boundary, and also precipitates Fe, C, and B compounds at the grain boundary.