POWDER METALLURGY BASED MANUFACTURING PRODUCES HIGH WEAR RESISTANCE COMPONENTS

A new activity with GSTP and the The Welding Institute in the UK has found that powder metallurgy could be used to make components able to withstand high temperatures and extreme amounts of wear.

Components with these properties are extremely useful on space craft, where parts are touching and interacting with each other, moving against each other and over time could become worn down through the friction process.

One specific application the activity looked at was manufacturing a mechanical gas seal – a device that needs to be extremely geometrically accurate so that it would seal very tightly and would not allow gas to escape and has a lot of pressure behind it so needs high wear resistance.

Powder metallurgy is the overarching term for different manufacturing methods that use powder as a raw material in their process. Oftentimes the novelty and advancement over other processes is that can build and shape the parts by adding on top of itself and near to the final shap (net-shape) however you want from scratch, instead of more traditional methods which normally machine down a large block of material into the shape needed. By building from a powder filament, called a feedstock, there is less wastage and upfront costs for materials. The process saves time too as machining parts often takes longer. A process called Hot Isostatic pressing (HIP) was chosen, for that the activity had to make HIP cannisters – which have a negative form of the final component geometry in, then powder is filled into this form, before pressure and heat is applied. The product removed from the form is very nearly a finished part.

After modelling the negative form extensively for shrinkage and to verify the final geometry, the manufactured part underwent extensive testing to see if it could withstand harsh conditions.

The activity successfully developed both a gas seal, and a thruster combustion chamber – a propulsion device to demonstrate the manufacturing processes resistance to heat as well.

The underutilised process of HIP powder mettalurgy can now target many more space applications.

G61A-006QT completed at the end of 2021.