热轧过程对T7钢帘线组织与性能的影响

Influence of hot rolling process on microstructure and mechanical properties of T7 steel cord

定量分析观察了国产和进口T7钢帘线盘条产品的微观组织、硬度和不同部位的织构,并对国产T7钢盘条在1060℃开轧和900℃、800℃、750℃终轧的条件下进行了热轧加工的热模拟试验。结果表明,随终轧温度的降低,珠光体球团尺寸因奥氏体晶粒减小而减小,冷却速度降低使珠光体片层间距增大且硬度下降,盘条内外温度梯度升高而使表层软取向晶粒数目增多。分析表明,终轧温度应在850℃～900℃范围内适当选择。热轧冷却时应注意促使珠光体转变尽量在等温条件下完成,以保持珠光体片层间组织的均匀性和盘条良好的深拉拔性能。

The microstructure, hardness and texture in different sample layers of steel cord were observed and quantitatively analyzed. The hot deformation process of domestic steel cord was simulated using thermal simulation machine,while heating temperature was 1060 ℃, and finishing temperatures were 900 ℃, 800 ℃ and 750 ℃ respectively. The results indicate that the pearlite nodule size is reduced owing to decreasing austenite grain size with decreasing finishing temperature, while the interlamellar spacing of pearlite increases with decreasing hardness owing to the decreasing cooling rate and the grain number with soft orientation in the surface layer increases because of the increasing temperature gradient in the steel cord samples. It is believed that the finishing temperature should be chosen properly in the range 850 -900 ℃. The deep drawing ability of steel cords could be modified if the pearlite transformation is conducted under constant temperature, which leads to homogeneous pearlite lamellas.