DP780冷轧热镀锌钢板点焊接头的高速拉伸性能

High-Speed Tensile Properties of Spot Welded Joints of Cold-rolled Hot Dip Galvanized Steel of DP780

利用拉伸试验设备对1.2mm厚DP780冷轧热镀锌钢板点焊接头分别进行了准静态拉伸和高速拉伸试验,分析了点焊接头的高速拉伸特性,并与母材的进行了对比。结果表明:在准静态拉伸和高速拉伸时,点焊接头试样分别在一侧母材和过渡弧处发生断裂;准静态拉伸时的最大拉伸力为9.90kN,随着应变速率的增大,最大拉伸力逐渐增大,在应变速率为500s^(-1)时达到11.50kN;当应变为0.20~0.25时,点焊接头发生断裂失效,而此时仍处于母材的安全有效区间内。

The quasi-static tensile test and high-speed tensile test by a tensile testing machine were conducted on the spot welded joints of a cold-rolled hot dip galvanized steel plate of DP780 with thickness of 1.2 mm.The highspeed tensile properties of the spot welded joints were analyzed and compared to those of the base material.The results show that during the quasi-static and high-speed tensile testing,the specimens of the spot welded joint fractured in base material of one side and at the transition arc position,respectively.The maximum tensile stress was 9.90 kN in the quasi-static tensile testing,which increased with the increase of strain rate and reached 11.50 kN at strain rate of 500 s^（-1）.A fracture failure of the spot welded joint occurred when the strain was between 0.20-0.25,while the base material was still in the safe and effective range.