Abstract: The mechanical properties of Φ13 mm bar forged from 70 mm casting thin slab of high grade non-oriented silicon steel (/%: 0. 002 7C, 3. 06Si, 0. 32Mn, 0. 013P, 0. 004S, 0. 50Al, 0.002 7Ti, 0.004 2N) at elevated temperature 600 ~ 1 250℃ are measured by Gleeble-1500 stress-strain thermal simulation machine. Results show that with strain rate 1 x 10^-3 s^-1, only I brittle zone (1 250 ℃ to melting point) exists in the high grade non-oriented silicon steel, and the II brittle zone and Ⅲ brittle zone are all of no-occurrence. The main cause is that the extra-low carbon content ( ≤50 X 10^-6) and high silicon content (3%Si) in steel lead to no-course of α-γ-α phase transformation during silicon steel solidifying and cooling process to avoid the sulfur, oxygen etc elements in solid solution status in forms of ( Fe, Mn) 0, (Fe, Mn)S and AI₂O₃precipitated and grown at austenite grain boundary resulting in the strength of grain boundary decreasing and the cracks occurring.

摘要： 通过Gleeble-1500应力-应变热模拟试验机测试了由70 mm连铸坯锻成的Φ13 mm棒材的高牌号无取向硅钢(/%:0.002 7C,3.06Si,0.32Mn,0.013P,0.004S,0.50Al,0.002 7Ti,0.004 2 N)的高温(600~1 250℃)力学性能。结果表明,在应变速率为1×10^-3s^-1时,高牌号无取向硅钢中仅存在第Ⅰ脆性温度区(1 250℃至熔点),第Ⅱ脆性温度区和第Ⅲ脆性温度区均未出现,主要原因是超低碳(≤50×10^-6)、高硅(3%Si)致使硅钢凝固冷却过程中不经历α-γ-α相变,避免了固溶的硫、氧等元素以(Fe,Mn)O、(Fe,Mn)S、AI₂O₃等形式在奥氏体晶界沉淀和长大导致晶界强度降低,产生裂纹。