Hardfacing Materials

[gcb]

I would like to identify an alternative technique to electroplating for the application of a chromium carbide based hardfacing surface layer. Typically the layer would be 0.002" - 0.006" thick and should operate at temperatures of up to 700°C. The area to be coated is small and has a detailed geometry, so HVOF would not be suitable.

I would assume that PVD or micro-arc welding may be suitable tecniques, but if anyone can provide specific details regarding equipment and materials it would be very much appreciated.

Regards

 

[metengr]

What is the substrate material and wear application?

 

[gcb]

Hi,

This will cover a variety of components, but typically the material shall either be a 12% Cr, 2½% Ni steel or a Ni-based superalloy.

The main wear mechnaism would be fretting (the components are gas turbine parts).

 

[metengr]

gcb;
We also have a number of gas turbines. The fretting you mentioned, is this at the blade root location (rotating blades in the wheel and vanes) in the compressor section for the 12Cr (403 ss) materials?

 

[gcb]

All turbine stage materials, root location of stator assemblies for the 12%Cr steel.

 

[metengr]

Ok. Typically, I have not seen this type of hardfacing application for stator vane roots. We have had failures over the years due to HCF initiating from roots that were not properly machined for tool marks were left as stress risers. If you are observing actual fretting damage, I would go after tightening up the vane root tolerances. I would be concerned with attempting to solve the fretting damage to the vane root and transferring the wear damage to the stator.