Intermediate Frequency Spot Welding Performance Investigation of Precision Ultra-high Strength Quenching Steel Plate

In recent years the precision ultra-high strength quenching steel plates (PUHSQS) have been widely used in the automobile production to reduce weight and improve passive safety. This paper investigates the spot welding performance of PUHSQS EN 1029TL4225, a kind of advanced high strength steel, whose tension strength can attain 1500 MPa after being quenched. Using the intermediate frequency (IF) spot welding process, two kinds of welded joints are made: the joint of two PUHSQS plates and the joint between PUHSQS EN 10292TL4225 and the micro-alloy steel H340 LAD. The mechanical performances of welded joints, such as the tension strength, the hardness distribution, are tested. Besides, the macrostructure and microstructure are also analyzed. From the results, we can see that both of two kinds of welded joints have perfect properties and internal quality, and also the mechanical performances meet the actual production requirement completely. So we conclude that the steel EN 10 292 TL4225 has good spot welding performance.