Fiber Laser Welded AZ31 Magnesium Alloy: The Effect of Welding Speed on Microstructure and Mechanical Properties

Tensile and fatigue properties of fiber laser welded high strength low alloy and DP980 dual-phase steel joints

“…11a that multiple crack initiation occurred from the weld concavity where the surface welding defect occurs (Fig. 11b) fatigue fractograph were similar to those observed on the fatigue fracture surface reported for a FLW AZ31B-H24 Mg alloy [35]. The fatigue crack initiation in the present FLW DP980 steel would primarily be related to the stress concentration caused by the severe weld concavity (Fig.…”

“…However, the YS and UTS were basically unaffected by the FLW. As seen in Table 2 It was also of interest to observe that a joint efficiency (i.e., a ratio of the UTS of welded joints to the UTS of the corresponding BM [33][34][35]) of both FLW HSLA joints and FLW DP980 joints reached as high as about 94-96% and 96-97% (Table 3), respectively. These results were similar to those of Nd:YAG laser welding (94.1% for DP980 steel joints) [12] and CO 2 laser welding (96.9% for CP1180 steel joints [12]).…”

“…This observation corresponded well to that reported by Roesler et al [37] who pointed out that the fatigue strength of a material under dynamic cyclic loading was much more sensitive to the manufacturing process and materials than the static strength, and that the fatigue strength was also much more sensitive to the lower level cyclic load than the higher level cyclic load. Indeed, in the region of lower level of stress amplitude and longer life, the factors like surface conditions, residual stresses, localized stress concentration, surface protective coating, severe weld concavity and zinc inclusions in weldment are deleterious to fatigue life [35,36]. The fatigue data plotted in Fig.…”

Microstructure and fatigue crack growth behavior in tungsten inert gas welded DP780 dual-phase steel

“…The ultimate tensile strength (UTS) of DP780-BM was much higher than that of DP780-TIG, while the yield strength (YS) did not change much. The joint efficiency (i.e., a ratio of the UTS of welded material to the UTS of the corresponding BM [13,16]) reached 94.6%, which means that TIG is a viable weld process that leads to outstanding tensile properties approaching those of the base material. Fig.…”

The effect of laser beam wobbling mode in welding process for structural steels

“…Original laser welding of thick and long plates requires final preparation, alignment, fixation, and welding process control. This problem can be solved using twin spot laser technique with filler wire or hybrid arc-laser welding [6][7][8][9][10][11][12][13][14], but it will decrease the welding speed. One of the ways to solve this problem is the use of a laser beam wobbling mode.…”