Mixed welding of the mobile construction platform in the automotive industry

This paper examines the possibility to improve mixed weldability of pins to mobile platforms. There is an increasing demand for mixed joints made of hard-weldable steel used in civil engineering and the automotive industry. A good example of this is welding of movable platform elements such as a pin to arm joints. The pin is very often made of yield structural steel S690 QL (1.8928), while the arm of the movable platform is mainly made of DOCOL 1400M steel from the AHSS group (advanced high-strength steel). This kind of joint is not easy to manufacture due to the different chemical compositions and thicknesses of both grades of steel. The difference in the thickness of welded elements creates an additional difficulty. The main aim of this article is to determine the most appropriate welding parameters and select additional materials to obtain the correct joint with good mechanical properties, free from welding defects and incompatibilities. This article examines whether the application of micro-jet cooling technology during the welding process might help to overcome these issues. For the first time, micro-jet cooling was not used to weld these grades of steel. The welding parameters and the micro-jet cooling parameters were investigated.