What is stainless ‘galling’?
Galling is when two threads bind together and seize. It can be fairly common when using stainless steel fasteners. This seizing or ‘cold-welding’ can result in fasteners having to be cut away as un-threading is impossible.
When is galling likely to occur?
- With larger threads of stainless fasteners – say M10 and up – this is because of a greater surface contact area, therefore more friction occurs in installation, causing heat, and binding. But note that there is a risk of all thread sizes galling.
- Nyloc Nuts – the nyloc causes pressure between the threads, again causing friction.
- When the thread is under load –say a turnbuckle tightening wire.
- Dirt in the threads.
- Installing too quickly – have a look at this video illustrating this point – watch until 1:10. (Note Anzor does not stock the product this video promotes).
How to avoid galling
- Lubricate the threads – when it comes to choosing a lubricant, it is important to use a Nickel based stainless lubricant or a lanolin based lubricant, i.e. something that won’t react with the stainless steel. We stock Lanotec – a lanolin based lubricant, and Tef Gel which also prevents galling.
- Remove particles and dirt from threads.
- Moderate the installation speed to a low rate of RPM. If the threads are lubricated, you may be able to install at a higher RPM.
Good luck with your threading. For more information on galling, please see this article by ASSDA: Galling by the Australian Stainless Steel Development Association.
NB: This information is provided as a guide only and Anzor does not accept liability for the application of this information. For advice about stainless steel contact the Nickel Institute