The Carbon Steel Bull Plug is a solid, threaded fitting used to close off a threaded port on a pipe, valve, or fitting. Unlike a pipe cap (which is welded), the bull plug is threaded and can be removed if needed. It is typically used on small diameter lines (1/8″ to 2″) for drain ports, test ports, instrument connections, and temporary closures. The plug is forged from carbon steel ASTM A105 (the standard material for high pressure threaded fittings) and then machined with NPT or BSP threads. Hex head plugs are standard for wrench tightening. Round head plugs (with an internal hex) are available for flush mounting. The threads are tapered (NPT), so they seal by thread interference — typically supplemented with PTFE tape or pipe dope.
Why Choose Us / Advantage
Forged vs. Cast: Forged A105 is stronger and has no porosity — no leaks.
Grade B or 2H: Available in higher strength grades for high pressure.
Zinc Plated Option: Corrosion resistant finish for water service.
Full Thread Inspection: Threads checked with GO/NOGO gauges.
Stocked Sizes: 1/8″ to 2″ available for immediate shipment.
Technical Data
★ Specification Hex Head Round Head (Internal Hex)
★ Material Forged Steel ASTM A105 Forged Steel ASTM A105
★ Threads NPT or BSP (tapered) NPT or BSP (tapered)
★ Head Type External hex Round with internal hex
★ Pressure Class 2000 / 3000 / 6000 Class 2000 / 3000
★ Size Range 1/8″ – 2″ NPT 1/8″ – 1″ NPT
★ Coating Zinc plated / Plain / Black oxide Zinc plated / Plain
★ Sealing PTFE tape or pipe dope PTFE tape or pipe dope
Applications
● Closing drain ports on valves and equipment
● Sealing unused instrument connections
● Temporary closures for hydrostatic testing
● Air bleeder port plugs
● Hydraulic and pneumatic manifold closures
