IF steel cage type annealing process

Abstract

The invention discloses an IF steel cover type annealing technology, which is characterized in that a way of staged thermal insulation is adopted in the annealing process. Through the way, crystal grains have enough incubation period in the nucleation process, and the nucleation rate N of a re-crystallization can be improved. Due to the inverse proportion relationship between the size of the crystal grain of the re-crystallization and the nucleation rate of the re-crystallization, the nucleation rate N of the re-crystallization is improved, or the size of the crystal grain after the re-crystallization becomes small, so that the crystal grains are refined. Moreover, a gamma- structure is enhanced, and the second phase particles are small to be dispersed. The obtained IF steel products haveexcellent deep drawing property, thus solving the current difficulty that the IF steels with excellent deep drawing property are hard to be produced by the cover-type annealing furnace.

Description

technical field [0001] The invention relates to a heat treatment process for metallurgical products, in particular to an annealing process suitable for producing IF steel in a bell furnace. Background technique [0002] The production process of deep-drawn steel sheet (IF steel) for automobiles is complicated, and there are many factors affecting its final performance. The steel plate will produce different degrees of work hardening after cold rolling, resulting in residual stress inside the steel plate, which will adversely affect the performance of the steel plate. Therefore, IF steel must be annealed after cold rolling. The annealing process is a key process that determines the performance of the final product in the production of IF steel cold rolled plates. It can not only eliminate the residual stress and internal defects of the steel plate, but also complete the recrystallization and crystallization of ferrite. Grain growth and the development of recrystallized textu...

AI Technical Summary

Problems solved by technology

However, for users of high-grade products, the steel plate produced by this general annealing system is far from meeting the requirements of its deep drawing performance, and can only rely on continuous annealing to improve its performance.

However, at present, most domestic manufacturers adopt bell-type annealing, and each manufacturer is unwilling to spend a huge investment to replace the annealing equipment, so it is urgent to improve the annealing process to adapt to the current production of bell-type furnaces.

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