New steel material for additive manufacturing used by GKN Sinter Metals and Porsche Engineering

Today’s automotive manufacturers are faced with the ever-increasing demand of improving vehicle efficiency. Manufacturers have tackled the problem from all angles: reducing weight, creating more efficient internal combustion engines, improving powertrains, and reducing noise. But to achieve a more efficient performing vehicle, the automotive market has started using a new process.

Metal Additive Manufacturing (AM) brings a natural competitive advantage for time to-market contraction of new ideas and for the development of innovative solutions. AM is used for prototyping parts with quality fit and function. The process has also been used to mass manufacture parts that require a unique shape, typically impossible to achieve via traditional machining.

The development of more efficient and functional-integrated powertrains, combined with AM design freedom, brings the opportunity to develop specific AM steel grades that withstand high wear and loads in combination with functional integration and weight reduction.

GKN Powder Metallurgy developed a new powder material and manufacturing process that fits all the requirements of the automotive industry – the 20MnCr5 features desired characteristics that are key for parts for a host of industries:

  • high strength yet still ductile
  • high fatigue strength
  • excellent wear resistance through case hardening
  • inherent toughness, but still machinable

Porsche Engineering investigated how to implement the new material (click here to download the material datasheet) for components in their e-drive powertrains. Using the technique of structural optimization in combination with GKN’s AM and 20MnCr5, a unique design of the differential – including the ring gear – was developed. With this combination of weight reduction and stiffer shape of the gears, a more efficient transmission was achieved. As metal AM continues to progress and become a mainstream process, the application can be extended to not just prototyping or motorsport but also series production.

The Material and Mechanical Properties of 20MnCr5
In the laser powder bed fusion (L-PBF) technology field, there are several alloys that are currently available on the market for manufacturers. Considering iron-based alloys, two most important families of steel are identified as stainless steel and tool steel.

Source: sintermedia.gkn.com

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