Microstructure and properties of post weld heat treated2.25Cr1Mo weld metal
In the present investigation, 2.25Cr1Mo weld metals deposited with manual metal arc (MMA) welding and submerged arc welding (SAW) have been compared with respect to their tolerance to long post weld heat treatment (PWHT). Mechanical properties including the impact transition temperature have been determined and the microstructures have been characterised using light optical microscopy and field emission gun scanning electron microscopy.
As expected, the tensile strength and the hardness of the weld metals decrease with increased tempering time. Of greater interest is the impact toughness results. Analysing the 47 J impact transition temperature, the MMA weld metal withstands long duration PWHT better than the SAW weld metals. The microstructures suggest that this could be an effect of differences in bainite morphology and grain size, characteristics governed by the cooling rate and the chemical composition.
2.25Cr1Mo, post weld heat treatment, microstructure, tensile strength, impact toughness