Coated stud bolts: PTFE, galvanised and zinc-nickel
Coatings that protect bolting in coastal, offshore and chemical plant atmospheres and ease future dismantling.
About coated bolting
Coated bolts resist atmospheric corrosion and come apart more easily at the next shutdown. Thick coatings such as galvanising need oversized-tapped nuts, which we supply with the studs.
Grades
| Grade | Specification | Notes |
|---|---|---|
| PTFE fluoropolymer (Xylan-type) | Blue, green, black and other colours | Offshore, coastal, chemical |
| Hot-dip galvanised | ASTM A153 / F2329 type | Outdoor structures and piping |
| Zinc-nickel | Electroplated | Thin, uniform corrosion protection |
Need coated bolting? Get a price from the manufacturer.
Send diameter, length, grade, coating and quantity, or the flange list.
Bolt set finder
Studs and nuts per flange joint, with d, F and H on the drawing.
Bolt set finder
Studs and heavy hex nuts for any number of ASME B16.5 flange joints.
Stud length depends on facing and gasket thickness, so add those in your enquiry.
Threads, marking, testing and coatings
Threads
UNC up to 1 inch and 8 UN from 1⅛ inch, class 2A/2B, per ASME B1.1. Metric ISO threads on request. Threads rolled or cut.
Marking
Studs and nuts stamped with grade symbol and Teshi mark, and heat lot traceable to the test certificate.
Testing
- Tensile, yield and hardness per grade
- Proof load on nuts
- Impact tests for L7 and LTCS grades
- PMI on alloy bolting
Coatings and packing
Plain, hot-dip galvanised, zinc-nickel, PTFE (Xylan-type) and others. Packed in boxes or bags by size, labelled per joint set on request.
Questions buyers ask
Do PTFE coatings affect tightening torque?
Yes. PTFE reduces friction, so torque values for coated bolts are lower than for plain bolts. Use the torque table for the coating applied.
Get a quotation from the manufacturer
Send your BOQ, drawing or tender reference. You deal directly with the manufacturer.
- Reply from our estimation team, usually within one working day
- Carbon steel to titanium on one order
- EN 10204 3.1 or 3.2 certificates, third-party inspection welcome
- ISO 9001:2015 certified and IBR approved, since 1971
Drawings and BOQ spreadsheets are easiest by email. Mention your project name.