Plating & Coating
It is recommended that high-tensile fasteners are coated for use in Petrochemical or offshore applications; it both benefits the installation and maintenance but also the life of the assembly. Coating provides excellent corrosion protection and lubrication for fasteners under many and varied environments. Coatings are applied at the time of manufacture.
XYLAN - Blue & Green
A unique fluoropolymer chemistry incorporating plastics and corrosion inhibitors such as PTFE, Xylan coatings are commonly specified as the preferred option for improving the surface properties of offshore components. Xylan offers excellent corrosion and chemical resistance and works well under high loads and high temperatures. It will significantly reduce the friction coefficient of fasteners which facilitates even tension. The lowering of friction actually increases the effective tension of the fastener as a result of reducing the wasted shear stress.
- A non-stick thread lubrication available in many colours for easy identification
- Improves ease of maintenance and eliminates hydrogen embrittlement
- Working temperature range -250°C to 285°C
- Hex nuts are coated internally.
Molybdenum "Moly" Disulfide
Moly is a combination of molybdenum disulfide lubricant and high performance resins that are thermally cured to ensure a complete bond to the base metal material. Moly coating lubricates the thread by transferring between the two mating surfaces ‘sacrificially, this assists to lower the coefficient of friction and increase life of the fastener. Commonly used in applications where load carrying capacity, operating temperature and coefficient of friction are primary concerns.
- Corrosion resistant up to 350°C
- Provides an undercoat for epoxy paints
- Resistant to both acids and alkalis
Zinc plating is used as a common light duty anti-rust protective coating. With it’s high quality finish and consistent thickness, Zinc plating can be used as a base for further PTFE coatings. Zinc plating will eliminate hydrogen embrittlement problems and blocked threads that can occur with fasteners that are exposed to increased pressure and temperature.
Zinc Nickel is recognised as an environmentally safe alternative to other electroplating methods such as cadmium. Zinc Nickel can be used in applications to reduce the galvanic reactions of dissimilar metals.
Inorganic Zinc Silicate
Inorganic Zinc Silicate provides excellent protection in petrochemical, refineries and offshore application and can provide better corrosion protection when used as a base coat for lubricant type coatings.
Hot Dip Galvanizing (HDG)
A common treatment of high-tensile fasteners in which the material is submerged in molten zinc (above 450°C) producing a constant oxide coating that is formed in the final process as it becomes exposed to the atmosphere. The resulting galvanised coating is tough and durable, the process allows a consistent coating to internal and external surfaces providing excellent abrasion resistances. The dull coating in appearance is an important advantage of the process showing that the article is completely protected and gives an excellent guide to coating quality. Mechanical Galvanising is also possible on our studs and fasteners. A more expensive process than HDG, the obvious benefit over the latter is a very uniform coating thickness reducing thread issues at assembly. Please contact Hurtle Industrial Services staff for further information regarding mechanical galvanise coating.