应变时效对不同成分高强度管线钢力学性能的影响

Effect of Strain Aging on Mechanical Properties of High Strength Pipeline Steels with Different Compositions

通过拉伸、冲击试验研究了应变时效对三种不同成分高强度管线钢力学性能的影响。结果表明:随着应变时效预应变量的增加和时效温度升高,钢的拉伸性能恶化,表现为强度升高、屈强比增大、伸长率下降,拉伸曲线逐渐由拱顶型连续屈服曲线转变成吕德斯延伸型曲线;微合金元素钒和铌可以降低钢中的自由间隙碳、氮原子的含量,从而抑制应变时效后拉伸性能的恶化;应变时效后冲击韧性的下降由预应变引起,时效处理改善了冲击韧性;钒的加入恶化了冲击韧性。

The effect of strain aging on mechanical properties of high strength pipeline steels with three different compositions was investigated by using tensile test and impact test.The results show that with the increase of pre-strain and aging temperature,the tensile properties were degraded,which were characterized as the increase in strength and yield ratio decrease in elongation and the change of tensile curve from the round-house type continuous yield curve to the Luders extended curve.The addition of V and Nb could lower the content of free interstitial C and N atom in the steel,and the deterioration of tensile properties induced by the strain aging could be inhibited.The decrease in impact toughness after strain aging was caused by pre-strain,the impact toughness was improved by aging treatment and the V addition worsened the impact toughness of the steel.