Analysis of weld cracking in shotblasting chambers made of Hadfield steel

In fillet welds made of 18Cr-9Ni-7Mn austenitic stainless steel centerline cracks were established along the connection line of two solidification fronts in the weld. On the grain boundaries oxide and carbide films were identified. Hot cracks resulted from a combined activity of a large gap between plates and the resulting high tensile stresses occurring during cooling, free root surface of the weld in the large gap, and intergranular oxide and carbide films in the weld. Since the parent metal was cut with highly oxidating plasma and atmospherically corroded surfaces was not ground prior to welding, remelted surface oxides passed into the weld pool. The increased Cr content identified in intergranular oxide films results from Cr oxidation in the filler material.