Application Spotlight: Galling Resistance

Galling is identified as a form of mechanical wear that occurs when there is adhesion and friction between sliding surfaces. Oftentimes, galling is triggered under a compressive load. In other words, galling is also the result of the crystal structure of a surface slipping and tearing. It happens when the protective layer of chromium oxide has worn away.

Here’s a quick example to help you understand the detrimental effects of galling. Nuts and bolts that are forced to rub against each other generate friction and heat that can cause tiny welds to break. If left untreated, the heat and friction may rip and tear out portions of metal surfaces.

At A&A Coatings, we can tailor thermal spray coatings that provide top-notch galling resistance in stainless steel metal-on-metal applications. What’s more, our coating solutions can preserve the corrosion resistance properties of the base material.

Common Industries that are Affected by Galling Problems

Below is a quick look at some of the common industries that require coatings that feature galling resistance. Some of the industries include:

• The gas turbine engine industry: Galling can increase both repair and maintenance costs for blades and vanes that are widespread in this industry.
• The automotive industry: The galling process can occur in the piston and synchronizing rings of automobiles, causing more engine and transmission breakdowns.
• The oil and gas industry: Gate and seat valves that have galled can cause a premature shutdown due to an unexpected oil and gas leakage. This significantly increases repair and maintenance costs as well.

Tungsten Carbide Coatings Provide Galling Resistance

It is true that the potential for metal to gall can be reduced when one uses dry film lubricant coatings. In addition, stainless-on-stainless also dramatically reduces the chances of galling. However, it is highly recommended that you opt for modern thermal spray coatings such as tungsten carbide coatings. A large number of organizations from different industries have opted for this coating to be applied on one of the mating parts to make the surfaces dissimilar.

At A&A Coatings, we have coatings that are made from tungsten. This is the most refractory metal and has a melting temperature of more than 3000°C! What’s more, we can create refractory ceramic coatings from tungsten carbide. The latter also provides much needed corrosion and wear resistance in addition to their stellar anti-galling properties. It is recommended that you opt for the above combination when it comes to applications where the risk of galling is combined with corrosive and abrasive media, or when these factors can have a synergetic effect that accelerates surface damage.

Why Choose Our Galling-Resistant Coatings for Your Applications?

A&A Coatings has a diverse coating portfolio that features a large number of galling-resistant coatings. That’s why you can be sure that we can optimize mating materials for your particular application. Our dedicated staff will also work closely with you to develop your galling-resistant coatings by optimizing coating properties, such as:

• Sliding wear resistance
• Phase composition
• Microstructure
• Abrasion resistance
• Hardness

When you opt for our coatings, you can be sure that our thermal spraying coating processes leave minimum impact on the substrate materials. That means those substrate materials will not warp or distort. What’s more, we are constantly developing galling resistant materials that can be applied on a wide selection of substrates so you can be sure we can deliver superior coatings that meet your needs.