The softening effect, which occurs as an undesirable consequence of microstructural changes in the heat-affected zone as a result of the welding process, is an inherent aspect of welding high-strength low-alloyed steels. One of the recommended ways to minimize these changes is the application of laser beam welding as a lower heat input technology. Hence, this work compares and investigates the effects of laser beam welding on the weld joint properties of S690QL, S960QL, S1100QL, S700MC, S960MC, and S1100MC steels. This research operates on the assumption that the mechanical properties of the zones surrounding the soft zone—base metal and weld metal—affect the mechanical properties of weld joints as well. The work shows that the total value of yield strength, tensile strength, and elongation of welded joints increases when the value of the strength of the weld metal and the soft zone increases and when the width of the soft zone narrows, and vice versa. Furthermore, the study demonstrates that the amount of C, Cr, Mn, Mo, Cu, and Ni in steel as well as the thermal cycle is directly associated to strength in these zones. The findings indicate that although the welded joints’ yield strength and tensile strength values remained over 96% of the base metal’s value, in certain cases the elongation values decreased to a mere 21% of the base metal’s value.

软化效应是焊接过程中热影响区微观结构变化的不良结果，是焊接高强度低合金钢的固有问题。尽量减少这些变化的推荐方法之一是应用激光束焊接作为较低热输入技术。因此，本工作比较并研究了激光束焊接对 S690QL、S960QL、S1100QL、S700MC、S960MC 和 S1100MC 钢焊接接头性能的影响。这项研究的假设是，软区周围区域（母材金属和焊缝金属）的机械性能也会影响焊接接头的机械性能。研究表明，当焊缝金属和软区的强度值增大以及软区宽度变窄时，焊接接头的屈服强度、抗拉强度和伸长率的总和值增大，反之亦然。此外，研究表明，钢中 C、Cr、Mn、Mo、Cu 和 Ni 的含量以及热循环与这些区域的强度直接相关。研究结果表明，尽管焊接接头的屈服强度和抗拉强度值仍保持在母材值的 96% 以上，但在某些情况下，延伸率值仅降至母材值的 21%。