Plate samples were sampled from A, B two kinds of rolling state of the X70 SAWL pipe with large deformation resistance.The stress-strain curve of tensile performance was inspected by using plate sample, the strain hardening exponent (n value) were calculated, the strain aging and the distribution rule of rolling state on n value were studied. The results showed that the statistical average n value of the B state samples is 0.116 0 before aging, and the value is 0.112 0 after aging, the value reduced by 3.4%; the statistical average n value of the A state samples is 0.115 0 before aging, and the value is 0.105 4 after aging, the value reduced by 8.3%. The n value is linearly proportional to yield ratio and yield strength. The 0.8% and 1.4% expanding rate have little difference on strain hardening exponent (n value), but the 1.4% expanding rate corresponding to uniform elongation decreased significantly, the uniform elongation value of 1.4% expanding rate is lower about 2% than that of 0.8% expanding rate.%从A、B两种轧制状态的X70抗大变形钢板制成的钢管中取样,用板状试样测定了拉伸应力一应变曲线,计算了该钢的应变硬化指数n值,研究了时效及两种轧制状态的n值分布规律.结果表明,工艺B状态的钢管时效前n统计均值为0.1160,时效后n统计均值为0.1120,下降约3.4％；工艺A状态的钢管时效前n统计均值为0.1150,时效后n统计均值为0.1054,下降约8.3％.X70工艺B状态钢管的n值、屈强比及屈服强度呈明显线性关系.0.8％和1.4％扩径率对应钢管的应变硬化指数n值差别不大,但1.4％扩径率对应钢管的均匀延伸率均值下降明显,比0.8％扩径率对应钢管均匀延伸率均值低约2％.
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