[问]钢筋经过冷拉后,为什么屈服点提高了?钢筋的屈服强度和屈服点是不是一回事?屈服点是不是达到屈服强度的极限点?我们不很清楚,请给予解答。(辽宁省丹东市于庆江)[答]从试验机上可以看到,钢筋受拉后,产生变形,开始阶段,应力的增加和变形的增加成正比例(从应力-应变曲线图中看到的是直线关系),但当超过钢筋的弹性限度时,应 [Q] After the steel bars have been cold-drawn, why did the yield point increase? Is the yield strength and yield point of the steel bars the same thing? Is the yield point the ultimate point of the yield strength? We are not very clear, please give an answer. (Ying Qingjiang, Dandong City, Liaoning Province) [Answer] It can be seen from the test machine that after the steel bar is pulled, it is deformed. In the initial stage, the stress increases and the deformation increases in proportion (as seen from the stress-strain curve). Is a straight line relationship), but when it exceeds the elastic limit of the steel bar, it should be