Improved Galling & Corrosion Resistance on Oil & Gas Fittings
by Mia Grundtvig – Expanite A/S
The results of a long-term corrosion test show in particular the superiority of the Expanite technology over traditional methods.
A horror for every assembler: galling of stainless steel fittings. A drop of lubricant on the thread helps, but what if, due to for example hygienic requirements, no lubricants may be used, or it is simply forgotten?
Stainless steel, with its excellent corrosion resistance, has the disadvantage that when having steel-to-steel contact, it tends to gall. Applying coatings such as DLC or diffusion processes such as Kolsterising® carburizing, nitrocarburizing or plasma nitriding have proven effective in counteracting this effect. However, these processes are not only very costly, but also generally have a negative effect on corrosion resistance.