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Black forged steel square-head plug, four-inch MNPT threads

Anvil

Anvil 0361302409 Square Head Plug 4" MNPT Black Forged

SKU CH-T5B4-5F01C

Forged steel square-head plug with MNPT threads for 4-inch Schedule 40 and 80 pipe, rated to 300 psi at 150 °F

  • Fits 4 in nominal pipe size for secure closure
  • Forged steel A105 construction withstands 300 psi at 150 °F
  • Operates from -20 °F to 350 °F across demanding environments
  • Square drive enables positive wrench engagement during installation
  • Compatible with Schedule 40 and Schedule 80 threaded systems

4 Inch Forged Steel Plug

This Anvil plug is a 4 inch nominal pipe size fitting made from A105 forged steel. It features a square head drive style and male NPT threads for secure installation. The solid construction suits Schedule 40 and Schedule 80 piping systems. It is supplied new without pre-applied thread sealant.

Installers Needing High-Temperature Steel Fittings

The plug handles a maximum operating pressure of 300 psi at 150 degrees F and a temperature range from -20 degrees to 350 degrees F. It fits black steel pipe in industrial or commercial plumbing. Buyers who need a plug with an integrated seal or pre-applied sealant should look at a different fitting type.

Sustained Pressure And Temperature Performance

Under continuous load the forged A105 body maintains its pressure rating up to the 300 psi limit at the rated temperature. The solid steel construction resists deformation during prolonged exposure to heat and pressure cycles. Thread integrity remains stable across the full operating envelope without relaxation.

How it compares

Measured against everything we stock in Bath Accessories & Soap Dispensers, at today’s prices. Recalculated every night.

Price $74.99
Pricier than about 66% of the 1,499 comparable items (median $39.99).

Specifications

Product
Brand nameANVIL
Product typeOther

Questions about this item

What pipe schedule must my system use for this 4" MNPT square-head plug to seal correctly?

The plug is rated for Schedule 40 and Schedule 80 pipe, so your piping must match one of those schedules.

Will the A105 forged steel hold up if I keep my existing 300 psi steam lines that run at 150 °F?

Yes, the maximum operating pressure is 300 psi at 150 °F, matching your current conditions.

How can I verify the plug is seated properly after installation?

Pressurise the line up to 300 psi at 150 °F and check for leaks; the solid forged construction and square drive give a positive mechanical stop when fully tightened.

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