Ti和正火工艺对Nb-V-Ti微合金电机轴用钢16MnT低温冲击韧性的影响

试验16MnT钢(/%:0.14~0.15C,0.27~0.30Si,1.40Mn,0.008~0.010P,0.003~0.004S,0.020~0.025Nb,0.10V,0.002~0.08Ti,0.025~0.027Al,0.0043~0.0053N)的生产工艺流程为60t EAF-LF-VD-5.8t铸锭-锻造φ190~250mm棒材-920℃正火。检验结果表明,0.08%Ti 16MnT钢锻造正火后-20℃冲击功为6~16J,低于标准值34 J。分析结果得出,0.08%Ti钢中存在大量TiN和延晶Nb-Ti(C,N)析出相,-20℃钢的断口为典型沿晶脆性断裂,且锻材断面的组织不均匀,表面为索氏体,心部为铁素体+珠光体。通过将钢中Ti含量降至0.002%,正火风雾冷却时锻材间距离为1.5m,使16MnT钢锻材的-20℃冲击功提高至132~288 J。