Steel used for hot galvanizing structural component with high yield ratio and manufacturing method thereof

Abstract

The invention provides steel used for a hot galvanizing structural component with high yield ratio, which comprises the following chemical constituents in percentage by weight: 0.02-0.10% of C, less than or equal to 0.1% of Si, 0.10-0.80% of Mn, less than or equal to 0.05% of P, less than or equal to 0.015% of S, 0.01-0.10% of T. Al, 0.002-0.02% of Nb, and the balance of Fe and inevitable impurities. In the invention, a hot rolling and annealing control process is adopted to obtain CQ-level precipitation strength steel with the tensile strength of 350-430MPa and good welding and surface quality. The composition system of the steel has low content of silicon and manganese, and does not contain chromium, molybdenum or other alloying elements, so the cost is low.

Description

technical field [0001] The invention belongs to the field of metal materials, and relates to steel for hot-dip galvanized structural parts, in particular to steel for hot-dip galvanized structural parts with high yield ratio. Background technique [0002] In the past few decades, as steel for automotive structural parts, it has undergone several important changes and developments. At first, low-carbon aluminum-killed steel and phosphorus-containing steel were mainly used to improve the strength of steel plates through solid solution strengthening; based on automotive With the development trend of structural steel safety, weight reduction and energy saving, the use of high-strength steel plates has become the development trend of automotive structural steel; however, with the increase in the strength level of materials, carbon and phosphorus cannot be added in consideration of the welding performance of materials , so the material has gradually developed to be based on dual-p...

AI Technical Summary

Problems solved by technology

[0007] Since the annealing of hot-dip galvanized products is completed on the galvanizing line, it has to pass through a zinc pool at about 460 ° C. Therefore, while adding alloy elements to improve the strength, it is necessary to consider the platability of the substrate and the impact on the surface quality of automotive structural parts. When there are too many Si and Mn elements, it is easy to form enrichment on the surface during the annealing process, which affects the wettability of the substrate during galvanizing, and causes galvanizing defects such as missed plating.

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