热轧温度对TC20合金坯料冷轧成形性的影响

Effect of Hot Rolling Temperature on Cold Roll Formability of TC20 Alloy

研究了在1000,940,850℃不同温度热轧的TC20合金坯料在冷连轧过程中的变形与失稳情况,结合热轧棒材组织和室温压缩的实验结果,表明:热轧温度越低,冷轧成形性越差。850℃热轧的TC20合金棒坯纵向组织中α相呈连续纤维状,冷连轧成形性比较差,极限变形量仅40%左右; 1000℃的热轧坯料组织中β相占比增加,冷连轧变形量可以达到60%,同时,其室温压缩实验过程中断裂压缩率高,塑性变形阶段加工硬化速率较小。通过室温压缩实验可直观评价TC20合金丝材的冷轧成形性能。

In this paper, the deformation and destabilization of cold rolling TC20 alloy bars which were hot-rolled at 1000, 940 and 850 ℃ , were analyzed and compared. Combined with the microstrueture of hot-rolled bars and room temperature compression experiments, the result showed that the lower hot-rolling temperature, the poorer the cold-rolling formability. The bar hot-rolled at 850 ℃ possessed the longitudinal microstrueture of continuous fibrous α-phase, and cold deformation property was poor, about 40%. The bar hot-rolled at 1000 ℃ possessed more β-phase, the cold deformation reached up to 60%, and showed higher compression rate and lower work-hardening rate. The cold-rolling formability of TC20 alloy bar had a strong correlation with its room temperature compression performance, the bars with higher compression rate and lower hardening rate in the plastic deformation stage had better cold roll fotmability.