The Development of Hot Rolled Automobile Beam Steel Plates 500L-Z with Excellent Surface Oxide Layer

摘要

This paper has determined the compositions and hot rolling processes of the hot rolled beam steel plates with excellent surface oxide layer for automobiles by investigating the oxide layer forming principle and its influence factors, and the feature of the steel oxide layer. The microstructure, mechanical properties, oxide layer shape and structural composition of the steel plates are analyzed by using metallographic structures examination, SEM analyzing, X-ray diffraction instrument and mechanical properties testing. The result shows that the trial hot rolled frame steel plates have an excellent oxide layer adhesion, the Fe3O4 proportions is greater than 85% in the oxide layer, and the oxide layer thickness is less than or equal to 10μm. The product has been trial-manufactured more than 100 thousands ton, and used to stamp the beam parts of automobiles straightly in no pickling process. The oxide layer scarcely scales off from the steel plates, and the effect is remarkable.