Effect of Solid Solution Carbon Content on Mechanical Spectroscopy of Automotive Mild Steel Sheets

摘要

Mechanical spectroscopy of automotive mild steel sheets with different carbon content is tested from room-temperature to 350℃．It can be found that continuous annealing deep—drawing IF steel has no dumping peak. The low carbon alu— minum killed steels with 0．025％and 0．049％carbon content appear Snoek peak and Skk peak,the height of snoek peak and Skk peak is similar between two kinds of aluminum killed steel. Based on theory of internal friction,the character of mechanical spectroscopy of automotive mild steel sheet is discussed also considering metallography and mechanical property. The result indicates that the peaks are all carbon peaks. The IF steel has no peak because carbon content is fixed by alloy elements to form precipitates. And so,there are no yield point elongation and ageing tendency for IF steel. After aging treatment in continuous annealing process,most of carbon element forms Fe3C and precipitates in low carbon aluminum killed steel. The mechanical property is different because of difference in volume fraction of Fe3 C precipitates. So,the amount of solid solution carbon is similar,on the other hand,the peak height of mechanical spectroscopy is similar. It is also pointed out the relationship between Skk peak,snoek peak and yield point elongation,ageing tendency respectively for low carbon aluminum killed steel in this paper.