Effect of Over-ageing on the Mechanical Properties and Microstructure of Cold Rolled Low Carbon Si-Mn Dual Phase Steel Sheets
ZHU Xiao\|dong, WANG Li, JI Si\|kai, WANG Cong (Technical Centre of Baoshan Iron & Steel Co. Ltd, Shanghai 201900,China)
Effect of over ageing on the mechanical properties and microstructure of Si Mn dual phase steel sheets was studied. It is found that the mechanical properties of the steel are greatly affected by over ageing temperature. The yield strength and YS/TS ratio of the steel aged between 300～350℃ increase sharply, meanwhile the yield point is observed. Over ageing time has similar effect as that of over ageing temperature. The increase of over ageing temperature only causes moderate decrease of martensite volume fraction but the influence of ageing temperature on the morphology of martensite island is evident. So the decomposition of martensite islands at higher over ageing temperature is the most probable explanation for the drastic change of the ratio of YS/TS.
【CateGory Index】： TG156.92