(1. Manufactory Department, Shougang Jingtang United Iron and Steel Co., Ltd., Tangshan 063200, Hebei, China 2. Strip Technology Department, Shougang Research Institute of Technology, Beijing 100043, China)
Abstract:Against the low yield strength and tensile strength of 700MPa grade high strength weathering steel in 10mm and 14mm thickness specification, the microstructure was studied by means of metallurgical microscope and scanning electron microscope, the controlling situations during the steel-making and hot rolling process were checked, the effects of TiC solid solution and precipitation strengthening on mechanical properties were researched. The results showed that insufficiently implemented heating technology led to TiC incompletely solid solution and high cooling temperature led to Titanium precipitates alligatoring, which were the main reasons resulted in the unqualified mechanical properties. By means of chemical composition optimization and process technology adjustment, the fully solid solution of TiC was realized, the effect of Titanium precipitation strengthening was improved and the problem of unqualified mechanical properties was solved.