3/8 inch x 3-1/2 inch Black Steel Nipple

3/8" x 3-1/2" Black Steel Nipple – Threaded Schedule 40 Fitting for Low-Pressure Applications

The 3/8" x 3-1/2" Black Steel Nipple is a Schedule 40 pipe fitting used to join two female-threaded components in gas, air, oil, or hydronic systems. Manufactured from welded or seamless carbon steel pipe and finished with a black oxide coating, this nipple provides a durable and corrosion-resistant connection for systems not requiring galvanized protection.

The nipple features tapered NPT (National Pipe Thread) male threads on both ends, machined to ANSI B1.20.1 specifications. It is typically used in industrial, commercial, and residential mechanical piping systems where threaded connections are specified for assembly or maintenance access.

Product Characteristics

• ✅ Nominal Size: 3/8 inch
• ✅ Overall Length: 3-1/2 inches
• ✅ Material: Carbon steel (ASTM A53 or equivalent)
• ✅ Finish: Black (oil-coated) for corrosion resistance in indoor or dry applications
• ✅ Thread Standard: NPT threads per ANSI B1.20.1 on both ends

Standards and Compliance

• ASTM A733 – Welded and seamless steel pipe nipples
• ASTM A53 – Standard specification for carbon steel pipe
• ASME B1.20.1 – Threading specification for pipe fittings

Installation Notes

Thread sealant or PTFE tape should be applied to male threads prior to installation to ensure a leak-tight joint. Hand tightening followed by proper wrench torque is recommended. Avoid excessive force to prevent thread galling or distortion, especially in softer mating materials.

Typical Applications

Used in mechanical and plumbing systems including gas distribution, hydronic heating loops, compressed air lines, and low-pressure fluid systems. Suitable for use in new installations, system extensions, or replacement of damaged pipe segments where a short threaded connection is required.

Material Consideration

Black steel is commonly selected for gas and heating lines due to its mechanical strength and ease of joining with other Schedule 40 steel components. Not recommended for corrosive environments or potable water systems unless otherwise specified by code.