Improved Plasticity and Cold-rolling Workability of Fe-6.5wt%Si Alloy by Warm-rolling with Gradually Decreasing Temperature

The effects of warm-rolling process on the microstructure, ordering, mechanical properties and cold-rolling workability of Fe-6.5wt%Si alloy were investigated, where three processes of warm-rolling with the same total reduction of 93% were used, including (1) 500 °C/12 passes/total reduction of 93%, (2) 500 °C/3 passes/total reduction of 50% + 400 °C/9 passes/total reduction of 86%, and (3) 500 °C/3 passes/total reduction of 50% + 400 °C/5 passes/total reduction of 60% + 300 °C/4 passes/total reduction of 64%. The results show that compared with process (1) warm-rolling with constant temperature of 500 °C, process (2) and process (3) warm-rolling with gradually decreasing temperature can significantly improve the room temperature plasticity and cold-rolling workability of the Fe-6.5wt%Si alloy. For example, the three point bending fracture deflections are increased by 54.5% and 81.8% for processes (2) and (3), respectively, and the maximum reductions of single pass cold-rolling without edge crack are increased from 50% of process (1) to 55% of process (2) and 62% of process (3), respectively. The plasticity improvement of the Fe-6.5wt%Si alloy can be attributed to both reductions of surface oxidation degree and order degree of the alloy by warm-rolling with gradually decreasing temperature.