AddUp, headquartered in Cébazat, France, has released AlSl 420 steel, specifically developed for processing by Additive Manufacturing. The new material will enable tooling manufacturers produce more complex, efficient moulds, and is now available for all FormUp® 350 New Generation Powder Bed Fusion (PBF-LB) machines.
The company, a joint venture created by Michelin and Fives, is said to be one of the first players in the metal AM sector to offer data for implementing AISI 420 steel. Also referred to in German standards 1.4021 or 1.2083, this stainless steel has both high mechanical strength and good corrosion resistance.
“Unlike alloys specially designed for Additive Manufacturing, which require users to invest in developing suitable post-processing, we offer here a widely used grade,” stated Frédéric Sar, Materials Manager at AddUp. “With AISI 420, the post-printing operations are identical to those of parts produced by forging. Existing solutions in heat treatments, surface treatments, machining settings, and insert grades are directly applicable to printed parts.”
This allows manufacturers to have a wide range of treatments at their disposal, enabling them to target specific properties for each application. For example, the quenching/tempering type heat treatments already available for raw 420 steel enables additively manufactured parts to display tensile strength characteristics in the range of 1350-1980 MPa, with elongation at break values of 2-10%, depending on the tempering temperature. Standard surface treatments, such as nitriding, can also significantly increase the surface hardness of parts after machining.
The AISI 420 alloy does not contain cobalt or nickel, making it compatible with the requirements of the REACH directive.
AddUp recently installed a FormUp 350 New Generation machine at the Aachener Werkzeubau Akademie GmbH (WBA), a leading German technical center for tooling. Equipped with AISI 420 stainless steel powder, and the newly developed recipe, the machine was capable of additively manufacturing parts with porosity rates less than 0.05%.