Galling & It’s Prevention with SURSULF® a Tribological Engineered Treatment

Galling is a form of adhesive wear that is caused by the microscopic transfer of material between metallic surfaces normally during a sliding motion. The friction created tears material from one material and fuses it with the other causing seizure.

Tribology of Galling.

Galling occurs when the frictional forces are strong enough to cause adhesive wear.
These are the typical conditions that promote Galling:

  • Lubrication is missing/removed from the contact area.
  • Corrosion from damaged electroplated or painted surfaces.
  • Large amounts of force are compressing the surfaces together.
  • A material is ductile and has a crystal structure that promotes cohesive attraction.
  • Extremely smooth surfaces.

It occurs in a wide variety of industries where machines and engines are in operation, including automotive, aerospace, oil & gas and many others causing reduced production efficiency, machine performance or even damage to the machine.

The Anti-Galling Solution : SURSULF®

Through extensive development and tribological testing to evaluate the sliding wear behaviors of materials in different simulated conditions the HEF Group has produced several coatings & treatments to protect parts from galling. This article is focused on surface treatments of metallic parts, leaving our coating options for another day.

SURSULF® is a form of salt bath nitriding created to resist galling.
It accomplishes this by in serval ways:

A hard, yet ductile porous micro-layer is found on the surface yielding several benefits:

  • It inhibits the formation of frictional welding points.
  • It greatly improves the retention of lubricants.
  • Treated parts compatible with mating surfaces without surface cracking or exfoliation.

Micro porous layer is supported by a compound layer of Iron nitrides (primarily Ɛ-Epsilon type) and precipitated alloying elements which significantly improving their wear resistance.

Beneath the compound layer is a diffusion zone. This produces substantial improvements in fatigue resistance delaying the formation of subsurface fatigue failures such as pitting and flaking.

SURSULF® is globally available through the HEF Groups network of Techniques Surfaces (TS) companies. TSUK are based in Birmingham and have the largest salt bath pots in the country. Please contact us for further technical information or request a quotation.