GKN Sinter Metals has produced a new case-hardened low carbon alloy steel – 20MnCr5 – for use in additively manufactured gear prototypes (Courtesy GKN Sinter Metals Blog)

GKN’s Sinter Metals Blog, edited by Stephen Hoeges, Manager of Additive Manufacturing at GKN, has reported on the development of a new material by the company. In his report, Hoeges stated that GKN Sinter Metals, working with GKN Driveline, has produced a new case-hardened low carbon alloy steel – named 20MnCr5 – for use in additively manufactured gear prototypes.

As well as the ability to be case hardened, 20MnCr5 also features the following desired characteristics, which GKN states are key in parts for a host of industries. According to GKN, the material:

• is high strength while remaining ductile
• has a high fatigue strength
• has excellent wear resistance through case hardening
• is inherently tough, but still machinable

Manufacturing prototype parts in the new material uses a very similar process to the old, but the parameters and process have been optimised for the case-hardened alloy by carburising each component’s surface before quenching and tempering the part. Carburised components include gears of all kind, camshafts, universal joints, driving pinions, link components, axles and arbours.

Hoeges states that GKN can now manufacture parts made completely of 20MnCr5 and offer hybrid production; meaning that the company is able to combine different manufacturing techniques with metal AM. 20MnCr5 can also be combined with all weldable materials, which Hoeges states could create widespread potential for AM in the aftermarket sector, particularly regarding the production of low-volume spare parts.

Since completing its first small batch of 32 gear wheels in 20MnCr5 for a leading gearbox supplier, GKN Sinter Metals states that it has received numerous inquiries regarding its AM capabilities, and that it will continue working with GKN Driveline on applications for aftermarket sales.

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