Variation of Mechanical Properties in Large Steel Forgings.

摘要

In a continuing effort to determine the causes of mechanical property variation in large steel forgings, the effects of forging reduction on mechanical and metallurgical properties were examined. The related work previously conducted at Watervliet has been appropriately summarized in a recent report, WVT-TR-74001. The present study deals specifically with the metallurgical consequences of solidification and mechanical working. Accordingly, the aspects of nonmetallic inclusions, chemical homogeneity and microstructure were considered. For the range of forging reductions investigated (1.5:1 - 10:1); a reduction ratio of approximately 3:1 produced optimum average values in % RA, Charpy impact strength and fracture toughness. Also, the significant variations statistically determined in these parameters was accompanied by real variation in carbon concentration. Therefore, carbon segregation on a macroscale, is shown to be a major contributor to mechanical property variation in large steel forgings. (Author)