Aluminium alloy 5083 belongs to the family of high strength light alloys and in this respect is widely used in high performance engineering structures. However, aluminium–magnesium alloys are known to be susceptible to hot cracking in fusion welding. The objective of this study is the investigation of occurrence of hot cracking i.e. solidification cracking in the weld metal and liquation cracking in the HAZ in Nd: YAG pulsed laser welding of a 5mm-thick 5083 –H321 aluminium alloy. The effects of peak power and frequency were studied. The cross section of welds were studied by metallographic techniques and the crack length were measured. It has been found out that with increasing peak both the weld penetration and hot cracking susceptibility increase. However, increasing the laser pulse frequency had reduced the occurrence of solidification cracking in 5083-H321 alloy.
