Phreakish
Mechanical
- Mar 14, 2008
- 10
I'm currently running a process by which a carbide die is yanked through a 4340 tube (2.5" od, 1.6" id) that is .05 larger than the initial hole. The carbide tools are G30 (tungsten carbide), and the 4340 is tempered to ~Rhc 21+-1, the length of the tube is approx 9". Typicall pull forces range from 275 to 350 BAR.
The issue is that we've had recurring 'galling' issues. 'Galling' may be a misnomer in this case, but its the termed used so far.
Observations:
Process: tubes are lightly coated with what appears to be an EP moly wheel bearing grease (black, sticky, industrial sized bucket).
The tools are typically 'wiped' clean, but not solvent cleaned - they rarely have much lube on them when the process begins.
At the end of the first stroke, we have metal transfer which varies from thin 'flake-like' formations that can be wiped away (almost completely, but not entirely) to actual smeared metal transfer (actual galling).
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The ID in the part is typically honed to size, with obvious (typical) honing marks remaining. Test blanks are cut to size with a boring bar, and as such the finish is quite different (these deposits tend to be flakier).
When the tool finishes its pass, there is typically no detectable lube on the contact surfaces. The finish of the ID shows 'polished' areas that relate to where the 'deposits' are found on the carbide tool.
What I'm looking for is a lube that can be applied to help eliminate the metal transfer. Or help with application techniques that may help based upon the above observations. Or am I up a creek?
The issue is that we've had recurring 'galling' issues. 'Galling' may be a misnomer in this case, but its the termed used so far.
Observations:
Process: tubes are lightly coated with what appears to be an EP moly wheel bearing grease (black, sticky, industrial sized bucket).
The tools are typically 'wiped' clean, but not solvent cleaned - they rarely have much lube on them when the process begins.
At the end of the first stroke, we have metal transfer which varies from thin 'flake-like' formations that can be wiped away (almost completely, but not entirely) to actual smeared metal transfer (actual galling).
-
The ID in the part is typically honed to size, with obvious (typical) honing marks remaining. Test blanks are cut to size with a boring bar, and as such the finish is quite different (these deposits tend to be flakier).
When the tool finishes its pass, there is typically no detectable lube on the contact surfaces. The finish of the ID shows 'polished' areas that relate to where the 'deposits' are found on the carbide tool.
What I'm looking for is a lube that can be applied to help eliminate the metal transfer. Or help with application techniques that may help based upon the above observations. Or am I up a creek?
