Galling
Galling
(OP)
Hi friends,
I have worked in valve industry . i am facing many times galling issue.
now i have faced one new issue. i have to make two matching parts with UNS N0 8825 material. will they gall?
Is there any material combination chart to prevent galling.or wht shd i take care for material selection to prevent galling.
Regards
Kamlesh
I have worked in valve industry . i am facing many times galling issue.
now i have faced one new issue. i have to make two matching parts with UNS N0 8825 material. will they gall?
Is there any material combination chart to prevent galling.or wht shd i take care for material selection to prevent galling.
Regards
Kamlesh





RE: Galling
The most common way to reduce galling is have a hardness difference of atleast 50 BHN. You can obtain this differeence through coating one surface, weld overlay, or cold working/anneal combo. Any coating system must resist the enviroment.
RE: Galling
RE: Galling
If not then you could change alloy on one of them, or use one in the cold worked condition to provide higher hardness.
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Plymouth Tube
RE: Galling
RE: Galling
thx a lot.
My both parts are wetted like trim. so they are movable one inside other. so will coating work? Little worried for that.
RE: Galling
RE: Galling
RE: Galling
I think applying TDC or XADC to one of parts will reduce galling. Key is to keep hardness difference as large as possible and to have very fine finish. Peen other part for galling resistance. It work hardens surface and knocks down asperities.
BeCu is an option but doesn't always agree with strength and certain environmental concerns.
TDC has 78 Rc
XADC is TDC with diamond substrate = 98 Rc
It is applied in anodic bath.
I use TDC and it is the best anti galling thread coating
Coating is ~ .0006 thick
Molycoate 4300 is good dry film option.
Copper coating is typical coating called
out by premium thread vendors.
I would be interested in your choice and results.
I
- CJ
RE: Galling
Some reason that combination performed well. still cold worked pin and copper
Coated box.
- CJ