980MPa-grade hot-dip galvanized steel plate with high elongation and manufacturing method of 980MPa-grade hot-dip galvanized steel plate

Abstract

The invention discloses a 980MPa-grade hot-dip galvanized steel plate with high elongation, which comprises a base plate and a galvanized layer, the base plate comprises Fe and inevitable impurity elements, and further comprises the following chemical elements in percentage by mass: 0.17-0.25% of C, 0.6-1.2% of Si, 2.0-2.6% of Mn, 0.02-0.3% of Al, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = 0.1%, 0 < Nb + Ti < = The microstructure of the base plate is ferrite, martensite and retained austenite. In addition, the invention also discloses a manufacturing method of the 980MPa-grade hot-dip galvanized steel plate with high elongation, which comprises the following steps: (1) preparing cold-rolled strip steel; (2) carrying out pre-oxidation treatment in an open fire furnace so as to form a pre-oxidation film on the surface of the strip steel; (3) annealing is conducted, specifically, the annealing soaking temperature is 780-840 DEG C, and the annealing soaking heat preservation time is 60-120 s; (4) reheating: the reheating temperature is 450 to 470 DEG C; (5) hot galvanizing: the hot galvanizing temperature is 430-470 DEG C; (6) flattening; and (7) oiling.

Description

technical field [0001] The invention relates to a steel plate and a manufacturing method thereof, in particular to a hot-dip galvanized steel plate and a manufacturing method thereof. Background technique [0002] In recent years, with the rapid development of the automobile industry and the improvement of passenger safety awareness and national emission regulations, the market and users have also put forward higher requirements for the lightweight of automobile bodies. Therefore, in order to reduce the weight of the car body and ensure the safety of the vehicle, many automobile manufacturers require that the steel plate used in the car should take into account high formability, easy welding and good crash safety. [0003] Currently on the market, DP steel and QP steel are two types of steel plates commonly used in automobiles. Among them, DP steel has both manufacturability, welding performance and good mechanical properties, but has obvious shortcomings in light weight; w...

AI Technical Summary

Problems solved by technology

The typical composition of this cold-rolled hot-dip galvanized dual-phase steel is 0.19C-2.0Mn-0.3Si-0.7Al-0.45Cr-0.02Ti, and its yield strength is , tensile strength and elongation can reach 700MPa, 980MPa and 14% respectively, but high Al content increases the difficulty of smelting; high Cr content not only increases the cost of the alloy, but also is not conducive to the surface quality of galvanized sheet, high coiling temperature is also Significantly increased risk of surface defects

[0008] It can be seen that there are still certain defects in the existing hot-dip galvanized steel sheets in the prior art

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