Aging-resistant bake-hardened steel plate and galvanized plate and production method of aging-resistant bake-hardened steel plate

Abstract

The invention discloses an aging-resistant bake-hardened steel plate and a galvanized plate and a production method of the aging-resistant bake-hardened steel plate. The aging-resistant bake-hardenedsteel plate comprises the following chemical components of, in percentage by mass, 0.0011%-0.0017% of C, 0.015%-0.025% of Si, 0.16%-0.26% of Mn, 0.015%-0.025% of P, less than or equal to 0.003% of S,0.035%-0.065% of Al, 0.030%-0.050% of Ti, 0.009%-0.013% of V, less than or equal to 0.0030% of N, 0.007%-0.010% of B, 0.07%-0.09% of Nd and the balance Fe and inevitable impurities. Through reasonablechemical component design, the steel plate has good mechanical properties and good bake hardenability and aging resistance, meanwhile, parts manufactured by utilizing the characteristics of magnetizers formed in the components have good closeness, and the steel plate can be used for manufacturing car door inner and outer plates, engine hood inner and outer plates and other parts. Particularly, the structure of the steel plate is ultra-low carbon ferrite, and in the forming process, the high plastic strain ratio and the high strain hardening index ensure that the formability is good, and the cracking phenomenon is avoided; and meanwhile the size of the deformed part is kept stable.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular to an aging-resistant bake-hardening steel plate, a galvanized steel plate and a production method thereof. Background technique [0002] With the continuous development of automobile manufacturing, the selection of automobile materials is more scientific. The outer panels of passenger cars are required to have good dent resistance while thinning. In order to increase the dent resistance, bake-hardened steel is used on the outer panels of passenger cars. It has been widely used and the demand is increasing. Bake hardenability is a phenomenon in which the yield strength increases due to the free carbon of ferrite in the part being fixed to dislocations during paint baking, and steel sheets with excellent bake hardenability are easy to form before baking, and the final product is the body outer cover The parts are highly resistant to dents. Since there is a certain...

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Problems solved by technology

The C content in the steel composition system fluctuates too much, and the C content based on the upper limit will have an adverse effect on the aging performance, which will shorten the aging period and reduce the aging resistance; its high P content is not good for secondary processing brittleness; its The coiling temperature is 680-740°C, with a large fluctuation range, and it is difficult to ensure the stability of the through-coil baking hardenability and aging resistance; the flat elongation is 0.5-1.20%, and the yield platform will be longer, which will affect the aging resistance and formability. Adverse effects, strict control of other process windows needs to be increased, increasing the difficulty of controlling other process links in the whole process

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