Prevention of Fracture of Cracked Steel Bars Using Laser: Part III—Case of High Carbon Steel

Abstract

The effect of laser welding on prevention of the fracture of cracked shafts of a high carbon steel are presented. Static tensile strength and rotary bending fatigue strength were obtained using shaft specimens of AISI W1 which were welded by a CO2 laser around a precrack. Since the welded region became extremely hard and brittle, both the strengths of laser-welded specimens were lower than those of non-welded specimens. However, the strengths were increased higher than those of non-welded specimens after tempering the specimens. It was found that when tempered at 600°C after laser welding, the rotary bending fatigue strength of specimens with a crack smaller than 12 mm rose similar to that of the base metal, and when tempered at 700° C, the static tensile strength of specimens with a crack smaller than 12mm rose similar to that of the base metal. Therefore, it was shown that the laser welding is very effective to prevent fracture of high carbon steels.