Microstructure and hardness of spray-formed chromium-containing steel tooling

The microstructure and hardness of a spray-formed chromium-containing tool steel H13 were studied. There is very little porosity in both as-spray-formed samples and spray-formed samples following heat treatment. The microstructure in the as-spray-formed material is characterized by proeutectoid carbides, lower bainite, martensite, and retained austenite. Spray-formed H13 aged at a given temperature exhibits higher hardness than commercial H13 conventionally heat treated and tempered at the same temperature. The microstructures and hardness are rationalized on the basis of numerical analysis.