Research on Homogeneity and Service Performance under the Liquid Core Forging Process

Assab 718 die steel was used to complete the anatomical tests of the modules produced by two different forging processes consisting of the traditional forging process and the liquid core forging process. The homogeneity and the service performance were compared in the composition, microstructure, mechanical properties, resistance to corrosion and surface roughness. The liquid core forging process improved the uniformity of the distributions of C, Cr and Mo elements. The macrostructures had no obvious defects and the grains at the half position were finer and more evenly distributed. The nonmetallic inclusions grade in the large module met the delivery requirements, while the module under the traditional one had ultra-wide sulfides. The section hardness and the tensile properties were more uniform. The Assab 718 was more corrosion-resistant through the electrochemical tests under the liquid core one. The laser confocal microscope tests showed it had a better polishing performance.