Study on the Properties of Spray Formed Tool-Die Steel

The T15 high speed steel (HSS) spray formed (SF) billets were manufactured using a twin-atomizer spray forming facility at Beijing Institute of Aeronautical Materials (BIAM) AVIC, China. The billets were then hot isostatically pressed (HIP) following hot forge (HF) and heat treatment (HT). The as-spray formed billet is integrally dense and has a high relative density of >98%, and the macrostructure is free of macrosegregation. The microstructure consists of polygonal grains of 20µm with tempered martensite inside the grains and refined carbides uniformly distributed along the grain boundaries. Hardness and three-point bending properties were also measured. The spray formed materials was comparable to those made by powder metallurgy in terms of microstructure uniformity, hardness and bending property.