Apexia Metal

Xylan Coated B7 Studs, Teflon Nut Bolt & washer supplier in India

Generally, ceramic, zinc flake, and Xylan or PTFE Coated Bolts and Nuts are coated by spraying. Any conventional air spraying method covers the surface of these screws, followed by a curing process. The follow up curing process sets in the coat and increases the endurance of the finish. PTFE Coating Bolts, Stud Bolt & Nut improves the lifespan.

PTFE coated Bolts and Nuts are known for exceptional corrosion resistance, low coefficient of friction, consistent tensioning and subsequent ease of installation and removal. Extensive testing and field use have proven that the future of Teflon Coated B7 Stud Bolts lies with Fluoropolymer coatings. Earlier hot dip, galvanized, cadium or zinc plated Studs were considered the standard. But these coatings are not suitable in corrosive atmospheres prevalent in many industries. PTFE coated B7 studs with 2H nuts are widely used in various applications.

The process to electroplate a fastener starts with its cleaning its surface in an alkaline detergent solution. After cleansing its surface, the screws get treated with an acid. The acid removes any rust or scales present on the surface. Thorough sterility is a prerequisite for this process as the molecular layers of oil or rust can prevent adhesion of any coating to the metal surface. While the main objective of applying a coat on the fastener, is its protection; there are instances during cleaning or pre-cleaning, wherein there is the absorption of some hydrogen content. If these hydrogen absorbed screws are a part of a sour-well environment, there is a risk of the fastener becoming susceptible to Hydrogen embrittlement; And PTFE Coated Fasteners are rendered useless. Fasteners that belong to strength classes  10.9 and above, as well as USA grade 8, are most likely to witness hydrogen embrittlement. To prevent this, the coated undergoes baking, although complete elimination of Hydrogen embrittlement in screws is not a guarantee.