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Hexagonal malleable iron locknut, dark grey finish, 2 inch FNPT thread

Value Brand

Value Brand 520-908HC Malleable Iron Hex Locknut Class 150 2 in

SKU CH-NR3A-5D1T6

Malleable iron hex locknut with FNPT connection rated for 300 psi at 150 °F and 150 psi saturated steam service

  • Malleable iron construction resists cracking under stress
  • Class 150 rating handles 300 psi at 150 °F
  • FNPT threads connect directly to 2 in pipe
  • Meets ASTM A-197 and ANSI B 16.39 standards
  • Operates from -20 °F to 366 °F for steam service

2-inch Class 150 Hex Locknut

This malleable iron hex locknut provides a secure FNPT connection for 2-inch pipe systems. Rated to Class 150 standards, it suits plumbing and industrial piping installations requiring reliable threaded joints. The fitting meets ANSI B16.39 and federal specification WW-P-521 for dimensional conformance.

ASTM A-197 Material Compliance

The locknut is manufactured to ASTM A-197 material specification, ensuring consistent malleable iron quality for mechanical strength. This standard governs the casting properties that affect thread integrity and pressure containment. No additional coatings or sealants are included with the fitting.

Pressure and Temperature Limits

Verify that your system operates within a maximum pressure of 300 psi at 150 degrees F and saturated steam pressure of 150 psi. The temperature range spans -20 degrees to 366 degrees F, so confirm compatibility with your media and ambient conditions. Ensure the FNPT thread type matches the mating components before installation.

How it compares

Measured against everything we stock in Hose Fittings, Adapters & Clamps, at today’s prices. Recalculated every night.

Price $4.99
Cheaper than about 83% of the 2,955 comparable items (median $17.99).

Specifications

Product
Brand nameZoro Select

Questions about this item

How often will the malleable iron hex locknut need replacement in a typical plumbing system?

The locknut is made from malleable iron to ASTM A-197 and conforms to ANSI B 16.39, so it is designed for the service life of the piping system and does not have a scheduled replacement interval.

What is the first pressure or temperature limit reached under sustained use?

The maximum working pressure is 300 psi at 150 degrees F, and saturated steam pressure is rated at 150 psi; the temperature range extends from -20 to 366 degrees F.

Does the locknut generate any noise, heat or power draw when installed in a continuously running system?

As a passive mechanical fitting with FNPT threads, it has no moving parts, draws no power, produces no heat of its own and creates no audible noise during operation.

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