Extensive testing and development has been carried out to optimise AM process parameters for maximum density and productivity and minimum surface roughness. Supported by microstructural analysis and mechanical testing, GKN’s researchers state that they have achieved a density of 99.9% in finished parts made from 20MnCr5.

While high residual stress can be a challenge, the company states that this too has been successfully reduced through process parameter optimisation. The case hardening process used on 20MnCr5 was also developed with a focus on standard requirements for surface hardness and case-depth profile.

Thanks to its increased core strength and wear resistance, GKN believes that the availability of 20MnCr5 for Additive Manufacturing will benefit a range of components, including gears, camshafts, universal joints and link applications. Following completion of the first small batch of one hundred gear wheels for a leading gear box supplier, the company reports that it has received a number of enquiries regarding the material’s AM capabilities and now has several collaborative projects in development.

A primary application for 20MnCr5 will be in aftermarket sales for the automotive industry. The material is highly suitable for the manufacture of spare parts on-demand, and GKN will also offer hybrid production, combining AM with different manufacturing techniques to achieve optimum results. A key advantage of 20MnCr5 is its ability to be combined with all weldable materials, making it possible to offer spare parts in low volumes at reduced costs.

“New materials developed by GKN are challenging established paradigms about material performance and robustness. Our cutting-edge materials and innovative manufacturing processes enable us to offer our customers around the world valuable, effective solutions to extreme product challenges,” explained Guido Degen SVP Business Development & Advanced Technology. “This is all in line with our commitment to deliver sector-leading, sustainable value for healthy, environmentally aware global growth.”

GKN Sinter metals will continue working with GKN Driveline on applications for aftermarket sales while expanding their AM capabilities with this new material.