The results show that the matrix in the microstructure occurs dynamic recovery and recrystallization and the materials generate cyclicsoftening during thermal cycling.
结果表明，在热循环过程中基体组织发生动态回复和再结晶，材料产生循环软化；
2
At lower annealing temperature obtain high strength and high yield ratio showed cyclicsoftening feature easily. That is detrimental to the using life of coiled tubing.
较低退火温度获得高强度、高屈强比易表现出循环软化特征，不利于提高连续油管的疲劳寿命。
3
Then, a logic computational diagram is constructed for calculating diametral growth by assuming fatigue cyclicsoftening, namely yield strength reduction as tubing fatigues.