Additive Processing of a X22CrMoV12-1 Steel: Structure, Properties and Product

Abstract

A high-strength steel X22CrMoV 12-1 was fabricated using the laser powder bed fusion (LPBF) process with optimized parameters to result in a nearly dense (99.95%) coupons in the as-printed condition. Trials to optimize the heat treatment condition with respect to the microstructure were carried out. The first set of experiments involved Oil Quenching after 2 h and 8 h of solutionizing at 1020 °C, 1070 °C, 1085 °C and 1100 °C, followed by tempering at 660 °C, 690 °C, 720 °C, for 2 h. The optimized heat treatment was evolved as, solutionizing at 1070 °C, 2 h in vacuum followed by argon gas quenching and tempering at 660 °C, for 2 h, resulting in a tempered martensite microstructure. The as-printed micro-hardness was ~ 400 HV, while the oil quenched micro-hardness increased to 525 HV and the tempered hardness was at 270–280 HV. Tensile tests carried out at room temperature and at high temperature revealed that the tensile behavior resembles that of the wrought alloy. A set of prototype demonstration components were manufactured for a steam turbine and the tensile behaviour in samples made in these builds were also obtained demonstrating the potential additive manufacturing for such parts.