Assessment of the Structure and Properties of Manually Laser-Beam-Welded Joints of Steel DOCOL 1200M

The research work aimed to determine the effect of manual laser beam welding process parameters on the properties of butt joints made of 1.8 mm thick steel DOCOL 1200M. The test joints were subjected to non-destructive (visual and penetrant) tests as well as destructive tests including static tensile tests, bend tests, hardness measurements as well as macro and microscopic metallographic tests. The optimisation of welding process parameters enabled the obtainment of joints satisfying both visual and strength-related quality requirements. The tests revealed that the use of the so-called continuous-wave laser beam helped minimise the number of welding imperfections. As a result of the laser beam welding process, the hardness in the heat affected zone (HAZ) decreased to approximately 260 HV, if compared to that of 360 HV in the base material and 370 HV in the weld.