Powder content in powder extrusion moulding of tool steel: Dimensional stability, shrinkage and hardness

Powder extrusion moulding (PEM) is a versatile and cost-effective technology for producing bi-dimensional shapes, (e.g. tubes and profiles) from metals, ceramics and cermets. PEM quality is affected by powder content; therefore, three highly-filled polymeric compounds containing 50, 55, 60 vol% tool steel powder were prepared and extruded to profiles. Extruded parts were debound in cyclohexane and sintered in forming gas (Ar + 5% H2) to obtain dense, sintered parts. The dimensional stability, the shrinkage and the hardness were measured. Minimum shrinkage and higher dimensional stability were obtained when the powder content was the highest (60 vol%). Specimens with 50 vol% powder had the highest hardness due to the initial higher binder content and resulting carbon content.