Abstract: The nonuniformity of mechanical properties and micro structure in 1Cr18Ni9Ti butt joints of argon arc welding is investigated by means of their distribution in the weld zone measured by the metallographic study and microshear test. The results show that the most nonuniformity of mechanical properties and micro structure is located in the bond of the welded joint, and the bond is the weakest zone of the welded joint. The fatigue test of the welded joint also shows that fatigue cracks occur generally in the bond first, and that the nonuniformity of the welded joint makes fatigue life decrease about 40～60 percent.

Key words: welded joint, mechanical properties nonuniformity, metallographic study, mi cro sheartest