Secondary carbide dissolution and coarsening in 13% Cr martensitic stainless steel during austenitizing

• Online Access: http://hdl.handle.net/2047/d20002442

Cutting blades and knives in various forms are manufactured from martensitic stainless steel strips. The manufacturing process of these cutting knives comprises a hardening heat treatment, cutting edge formation, and shaping into product dimensions. In a production environment, the hardening heat treatment is typically carried out continuously using an in-line heat treatment system. Such a heat-treatment process enables high production speed and efficient through-put. However, a high speed in-line heat-treatment process is very sensitive to raw material variations. Such variations may arise from differences among the manufacturing processes employed at raw material suppliers as well as shipment to shipment quality variations from a supplier. Some of these variations can be very subtle and might not have been fully understood by conventional material characterization techniques. The subtle material variations could cause differences in the response of the materials to the heat treatment, thereby potentially impacting the downstream manufacturability as well as the performance of the finished products. In addition, with the increasing demand for higher through-put production, optimizing the process parameters has become even more crucial. Therefore, the purposes of this work were to study the physical metallurgy of the hardening process and ultimately develop a simulation model to predict the kinetics of secondary carbide dissolution and coarsening during the austenitizing treatment of martensitic steel.