It is commonly believed that high alloy castings and welds are bound to have inferior corrosion resistance to their wrought counterparts as a result of the increased amount of microsegregation remaining in the as-cast structure. Homogenization and dissolution heat treatments are often utilized to reduce or eliminate the residual microsegregation and dissolve the second phases. Models are also available which aim to accurately predict the kinetics of homogenization and dissolution heat treatments. Detailed light optical microscopy (LOM) and electron probe microanalysis (EPMA) were utilized to correlate the amount of homogenization and dissolution present after various thermal treatments with calculated values and with the resultant corrosion resistance of the alloys.

The influence of heat treatment time and temperature on the homogenization and dissolution kinetics were investigated using stainless steel alloys CN3MN and CK3MCuN. Autogenous welds were placed on the surface of the as-cast samples to determine the significance of the structural scale. Volume fraction measurements and EPMA confirm that enhanced homogenization and dissolution kinetics are achieved in the autogenous welds when compared to the cast structures due to the reduced dendrite arm spacing (DAS). In both alloys, near-complete homogenization and dissolution is achieved in the autogenous welds at 1150 °C after only one hour due to the reduced DAS. The cast materials on the other hand require a 4 hour heat treatment at 1205 °C to achieve comparable levels of homogenization and dissolution. Available models are compared with the volume fraction and EPMA data, and reasonable agreement is found. Finally, it was demonstrated that the corrosion resistance of alloys CN3MN and CK3MCuN can be improved to match the corrosion resistance of their wrought counterparts.