高强度钢材对接焊缝拉伸性能试验研究

Experimental study on tensile test of butt weld of high strength steel

为考察不同匹配形式下国产高强钢对接焊缝的基本力学性能,对Q460D及Q690D焊接试件进行了静力拉伸试验。结果表明:对Q345B与Q460D及Q690D连接,在低强和等强两种匹配形式下的屈服强度和极限抗拉强度比较接近,极限强度比Q345B母材分别提高了约4.4%和6.5%,断裂位置在热影响区和母材区,说明不同强度钢材的混合焊缝连接,选用低强匹配的焊条能保证连接强度;焊缝区不先于母材断裂。对于Q460D和Q690D同种钢材对接焊缝连接,采用等强匹配试件的极限抗拉强度比低强连接分别提高了16%和14%,应变达到4.9%~11.9%,即达到极限强度值,说明同种钢材采用等强匹配的焊条,连接接头在承载力提高的同时,延性有所降低。

In order to research the mechanical properties of domestic high strength steel butt weld under different matching form, the experiment on static tensile about Q460 D and Q690 D is carried out. The results show that under the low matching and equal matching form,yielding strength and ultimate strength of Q345 B and Q460 D or Q690 D steel butt weld connection is relatively close,ultimate strength compared with the Q345 B base material is increased by about 4.7% to 6.5%,and the fracture position is mainly at the HAZ and base mental,which indicates that the section stiffness of the weld steel plate is improved and the weld does not break before the base metal. As for the same steel butt weld of Q460 D or Q690 D,the ultimate strength under the equal matching form is respectively improved by 16% and 14% than under the low matching form,the strain of the welded specimen reaches the limit strength value in the range of 4.9%~11.9%,it can be seen that the ductility of the same steel butt weld joint decreases while the bearing capacity increases under the equal matching.