Magnetic properties of welds in high-strength pearlitic steels

The magnetic properties of parent pearlitic steels, heat affected zones (HAZs), and weld metal have been measured and related to the differences in microstructure. Weld metal had a significantly higher coercivity and lower permeability than parent steel. The coercivities of weld metal from McDermott automatic welds were found to be higher than those from manual welds, a result of the small, lamella-shaped grains in the former materials. Subject to sampling uncertainty, for manual welds the magnetic properties from heat affected zones appeared to be intermediate between parent and weld metal values. Renormalization led to very similar properties in both microstructure and magnetic parameters for parent steel, HAZ, and weld metal. The Kneppo relation was found to hold in this case. A small anisotropy in the coercivity was found for weld metal, the greatest coercivity being in the welding direction. No variations were found in magnetic properties on variation of the heat input into manual welds