应变时效及去应力退火对未扩径钢管力学性能的影响

Effect of strain aging and stress relief annealing on mechanical properties of steel pipe without expansion

通过对应变时效去及去应力退火前后未扩径钢管拉伸、冲击、硬度、导向弯曲试验的对比,分析了应变时效及去应力退火对未扩径钢管力学性能的影响。结果表明,对未扩径的钢管先经过250℃应变时效,再经过600℃去应力退火后,未扩径钢管的力学性能得到改善,表现为母材的屈服强度、抗拉强度及伸长率升高,屈强比略有减小;焊缝的抗拉强度和硬度得到提高。母材、焊缝及热影响区的冲击性能略有下降,下降幅度对其冲击性能不会造成较大影响。经应变时效及去应力退火后焊缝弯曲试样未出现裂纹。合理的应变时效及去应力退火,可提高钢管的综合力学性能,且可以充分消除焊接残余应力。

Tensile property, impact toughness, hardness and bending tests were carried out on a steel pipe without expansion before and after of strain aging and stress relief annealing, and the effect of strain aging and stress relief annealing on mechanical properties of steel pipe without expansion was investigated. The results show that the mechanical properties are improved after appropriate strain aging and stress relief annealing, the yield strength, tensile strength and elongation of the parent metal increase, the yield ratio slightly decreases, however, the impact toughness decreases. There is no crack in bending test after strain aging and stress relief annealing. It is concluded that a suitable strain aging and stress relief annealing can improve the mechanical properties and eliminate residual stress of steel pipe without expansion.