Need solution to avoid thread galling

[Dineshkarthisan]

Hi all,
We are using lot of mechanical components which contains metric threads to assembly those component.we are facing thread galling issue in all those components.we are manufacturing the thread according to the standard thread gauges.While assembling those components the issue occurs.Both the components are made up of SS316L.

Please suggest any solution to avoid thread galling or any alternate method to avoid.

 

[drossfree]

anti seize should be used on all ss threads

 

[thebard3]

Unless the bolts are exposed to corrosive atmosphere, we tend to use carbon steel bolts to join stainless pipe section flanges. We have never encountered objectionable deterioration due to dissimilar metals. Even if using stainless bolts, as drossfree suggests, anti-seize should prevent galling unless it's a high pressure application requiring very high torque. When joining threaded pipe sections, it's a different story and all of the pipefitters claim to have their own combination of teflon tape, pipe dope and anti-seize in concert to prevent galling.

Brad Waybright

It's all okay as long as it's okay.

 

[MJCronin]

A much more detailed and informative discussion on SS thread galling:

https://www.eng-tips.com/viewthread.cfm?qid=18693

There is much more on this forum (and others)regarding galling prevention.

The US DOD prevents this problem through use of positive fastener identification and strict enforcement of fastener materials with significantly different hardness values.

Please try to make even the most cursory website search before posting the question

MJCronin
Sr. Process Engineer

 

[EdStainless]

If the tapped hole is soft (likely) then the fastener should be hard.
The threads need to rolled (not cut) and the material left hard.
And an anti-seize must be used.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[TimSchrader2]

Hello

We use alot of stainless bolts in a Ocean Atmosphere and use Tef gel to prevent galling.

 

[btrueblood]

In addition to MJ and Ed's advice you can look into using fasteners made from Nitronic 60 or similar alloys, which have good resistance to galling in a variety of material couplings.

 

[IFRs]

This is probably not relevant but we use all aluminum nuts on SS bolts. No galling!

 

[MJCronin]

I agree with btrueblood....... but not IFRs

Nitronic 60 and a similar alloy Gall-Tough were specifically developed to have superior resistance to galling and metal to metal wear. Nitronic 60 is much stronger that 304/316 SS and therefore makes it a good candidate for the nut material in a bolted connection.

https://www.hpalloy.com/Htmlpages/Nitronic60book.html

Nitronic 60 and similar materials were developed by ARMCO Steel (now AK Steel) in the early 1960s.

IFRs suggestion above to use aluminum nuts on stainless steel bolts is a terrible idea, IMHO..... The actual as well as calculated fastener strength would be severely decreased. There may also be a galvanic corrosion cell problem..

As always, my opinion only....



MJCronin
Sr. Process Engineer