Alloying hot-dip galvanized steel with tensile strength being 390 MPa-level and used for automobile and production method

Abstract

The invention provides alloying hot-dip galvanized steel with tensile strength being 390 MPa-level and used for an automobile. The alloying hot-dip galvanized steel comprises, by weight, 0.07%-0.10% of C, not larger than 0.03% of Si, 0.7%-1.0% of Mn, 0.010%-0.025% of P, not larger than 0.010% of S and 0.020%-0.070% of Als. The production method includes the steps of molten iron preprocessing; smelting with a converter and RH furnace processing; continuous casting, casting blank heating, hot rolling, coiling, acid pickling, cold continuous rolling, continuous annealing, hot galvanizing, alloying, finishing, on-line direct roller painting of self-lubricating paint and drying of a self-lubricating alloying plate. By means of the alloying hot-dip galvanized steel, it can be guaranteed that the yield strength ranges from 290 MPa to 320 MPa, the tensile strength ranges from 390 MP a to 440 MPa, the elongation percentage is not less than 36%, the roughness ranges from 0.4 microns to 1.0 microns, and the PC value is not less than 90; the ingredients and the technology are simple, and the cost is relatively lower; a better plasticity is achieved; meanwhile, through direct roller painting of a self-lubricating film, the pulverization level is upgraded to the first level; the pulverization resisting capability is excellent, and complex automobile inner plates and structural components can be stamped.

Description

technical field [0001] The invention relates to a galvanized steel for automobiles and a production method thereof, in particular to an alloyed hot-dip galvanized steel for automobiles with a tensile strength of 390 MPa and a production method thereof. Background technique [0002] With people's increasing emphasis on environmental protection and the development of automobile lightweight, the application of high-strength steel for automobiles is increasing. It is predicted that the proportion of high-strength steel plates used in automobiles will increase from 14% to 45% (100-294 kg) per car at present to 30%-70% per car in the future, of which about 70% of high-strength steel plates are Galvanized steel. Compared with hot-dip galvanized and electro-galvanized steel sheets, alloyed hot-dip galvanized steel sheets have superior corrosion resistance, welding performance and coating performance, and are widely used in the manufacture of automotive inner and outer panels. [0...

AI Technical Summary

Problems solved by technology

[0005] Although the above-mentioned documents all provide the production method of alloyed hot-dip galvanized high-strength steel, they all add a large amount of alloying elements, and the production cost is relatively high

In addition, there is no application of self-lubricating film, so its pulverization and peeling problems have not been effectively solved, resulting in poor stamping lubricity and poor formability during processing.

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