Microstructure Control and Correlation to Formability of Low Alloy Steel Via Flash Processing

摘要

Flash processing is promising in making formable steel from economical low alloy steel. Flash processing involves a rapid heating and cooling cycle with short hold times. Different sections of a low alloy steel sheet, AISI 1023, was flash processed to four different peak temperatures. A spherical biaxial dome test measured the formability of the steel. After peak temperatures of 1170 °C and 1270 °C, the steel formed, showing loads and displacements comparable to those of expensive martensitic steel grades. The microstructures were characterized to correlate the processing with the observed formability. A martensitic microstructure was observed, with an average hardness of 510 HVN. Although the distribution of the values of hardness were 100 HVN. A hardness band, 20 to 30 HVN harder, was observed near the centerline in the steel exposed to the highest peak temperature. The hardness heterogeneity and distribution has been correlated to the measured formability of the steel.