碳和硅对Mn系空冷贝氏体钢回火韧性的影响

Effect of C and Si on the Toughness of Mn-Series Air Cooling Bainitic Steel After Tempering

研究了碳的质量分数低于0.3%、不同硅含量的Mn系贝氏体钢的冲击韧性随回火温度的变化,结果表明,随着Si含量的提高,低温回火阶段出现韧性峰值的温度由220℃提高至340℃,韧性出现低谷的温度由340℃提高至520℃,这与Si抑制碳化物析出、稳定残余奥氏体有关。低Si钢一般适合高温回火后使用,高Si钢一般适合低温回火后使用;但碳的质量分数低于0.08%时,无论Si含量如何,低温或高温回火均适用,若碳含量过高,回火改善韧性的作用不明显。

Impact-toughness of Mn-series bainitic steel with carbon content less than 0.3% and different silicon content after tempering were studied.The results show that the temperature of peak value of toughness increases from 220 ℃ to 340 ℃ with increasing of the silicon content during stage of low temperature tempering,and the temperature of valley value of toughness increases from 340 ℃ to 520 ℃.It is related to the characteristics of Si that it can stable residual austenite,and inhibit precipitating of carbide. The steel may exhibit perfect toughness with low content of Si after tempered at high temperature, while exhibit good toughness with high content of Si after tempered at low temperature. The steel with carbon content lower than 0.08% can exhibit perfect toughness after tempered at low or high temperature, which is with no terms of Si. However, for the steel with high carbon content, it can not exhibit good toughness after tempered at any temperature.