Speciality steel manufacturer Daido Steel, headquartered in Nagoya, Japan, has released hot die steel-based powders for Additive Manufacturing. DAP™-AM HTC™ (Daido Alloy Powder for Additive Manufacturing with High Thermal Conductivity) is a cobalt-free powder suitable for Laser Beam Powder Bed Fusion (PBF-LB) Additive Manufacturing, based on H13 steel.
In the fields of aluminium die casting and plastic injection moulding, moulds have been additively manufactured using PBF-LB technology in order to allow more design freedom in cooling channels. Since PBF-LB uses lasers to melt and solidify metal powder in layers, thermal stresses can form in proportion to the size of the moulds.
Die steels like H13, with high hardness, are said to crack relatively easily during the Additive Manufacturing process. Another common option, maraging steel, is less likely to crack during moulding, but the thermal conductivity is lower than H13, meaning cracking may occur in the cooling channels. Another downside of maraging steel is that it contains cobalt, a substance that is regulated in Japan.
Daido Steel created DAP-AM HTC in an effort to mediate these issues. The powders are said to have conductivity 1.5 x greater than that of H13 and two times higher than maraging steel. With these attributes, DAP-AM HTC is said to contribute to shorter cycle times (due to lower mould temperatures) and improved mould lifespan (fewer heat cracks due to lessened thermal stress).
Several die-casting companies in Japan have evaluated moulds made from DAP-AM HTC and are said to have obtained favourable results. Daido Steel expects to continue the development of metal powders suitable for Additive Manufacturing machines and eventually expand the product lineup of the DAP-AM HTC series.