450MPa-level zinc iron alloy clad layer double-phase steel plate for car outer plate and manufacturing method thereof

Abstract

The invention discloses a 450MPa-level zinc iron alloy clad layer double-phase steel plate for a car outer plate and a manufacturing method thereof. Chemical components of the steel plate comprise, byweight percent, 0.05-0.08% of C, smaller than or equal to 0.005% of Si, 0.70-1.00% of Mn, smaller than or equal to 0.005% of P, smaller than or equal to 0.003% of S, 0.010-0.050% of Als, 0.20-0.40% of Cr, 0.05-0.20% of Mo, and the balance Fe and inevitable impurities. According to the steel plate, by means of low-Si design, moderate Cr and Mo hardenability elements are added, by means of technology control, at the low cold speed, the product physical performance can reach the yield strength of 260-300 MPa, the extension strength is 470 MPa-520 MPa, the ductility A80 is 32-36%, the n value is0.18-0.20, the roughness degree is 0.5-1.2 micrometers, the PC value is 100-150 per cm, pulverization is at the level 1-2, the clad layer surface is uniform in color and free of defects, the pulverization resistant performance is excellent, and production and manufacture of car coverage parts can be achieved.

Description

technical field [0001] The invention relates to the field of iron and steel smelting, in particular to a zinc-iron alloy-coated dual-phase steel sheet for 450MPa-level automobile outer panels and a manufacturing method thereof. Background technique [0002] With the continuous development of automobile lightweight and the continuous improvement of occupant safety requirements, the proportion and amount of high-strength steel in automobile body-in-white have increased in recent years. Due to its high strength, low yield ratio and good Formability, more and more favored by the automotive industry. At the same time, people's requirements for the corrosion resistance of automobiles are getting higher and higher, so the application proportion of galvanized dual-phase steel is also increasing year by year. The zinc-iron alloy coated steel sheet (referred to as GA steel sheet), compared with pure zinc sheet, has better corrosion resistance, coating and welding performance, and has...

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Problems solved by technology

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a zinc-iron alloy coated dual-phase steel sheet for 450MPa grade automobile outer panels and a manufacturing method thereof; Annealing, galvanizing and other process control to obtain a zinc-iron alloy coated dual-phase steel with dense and uniform coating surface structure, uniform color and no defect, and excellent anti-powdering performance, which can be used to manufacture automobile outer panels

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