The yield strength decrease of SSAW and ERW tube body can be attributed to both Bauschinger Effect and high springback stress incurred by manufacturing process.

• 制管过程中的包申格效应及制管过程中引入的高弹复应力 ,使螺旋焊管及直缝焊管管体屈服强度明显低于板卷屈服强度。