论文部分内容阅读
对两种不同厚度的Q345钢材和Ⅱ级对接焊缝连接件分别进行了落锤冲击动态拉伸试验,并与相同规格钢材试件静态拉伸试验结果进行了对比,研究了应变率对钢材和对接焊缝的破坏形态、屈服强度、极限强度及伸长率等动态拉伸力学性能指标的影响规律。试验结果表明,钢材在动态拉伸时表现出脆性断裂破坏趋势;对接焊缝连接件的破坏发生在母材区,焊缝保持完整,因此II级及以上对接焊缝试件的强度和延性可视为与母材相同。与静力拉伸试验结果相比,10mm厚钢材的伸长率稍有增大,断面收缩率变化不大;18mm厚钢材的伸长率变化不大,断面收缩率明显减小。随着应变率的增大,两种厚度钢材的屈服强度和极限强度有一定程度的提高,而伸长率和断面收缩率有降低的趋势。
The dynamic tensile tests of falling weight impact on Q345 steel and Ⅱ grade butt welded joints of two different thicknesses were carried out respectively and compared with the static tensile test results of the same size steel specimens. Butt weld failure morphology, yield strength, ultimate strength and elongation and other dynamic tensile mechanical properties of the law. The test results show that the steel shows brittle fracture failure trend under dynamic tension. The failure of the butt weld occurs in the base material area and the weld remains intact. Therefore, the strength and ductility of the butt weld of Grade II and above The same as the base metal. Compared with the results of static tensile test, the elongation of 10mm thick steel increased slightly, but the change of section shrinkage did not change much. The elongation of 18mm thick steel did not change much, and the reduction of area was obviously reduced. With the increase of strain rate, the yield strength and ultimate strength of the two kinds of thickness steel increased to a certain extent, while the elongation and the reduction of area decreased.