4 inch x 3 inch Black Iron Bushing

4 inch x 3 inch Black Malleable Iron Hex Bushing – For Pressure and Gas Line Transitions

The 4 inch x 3 inch Black Malleable Iron Hex Bushing is engineered to reduce pipe size in threaded systems while maintaining structural integrity under demanding conditions. Commonly used in natural gas, propane, and hydronic applications, this fitting provides a secure transition between larger and smaller diameter pipe connections in black iron systems.

Manufactured from ASTM A197 malleable iron and coated with a protective black finish, this bushing offers strength, corrosion resistance in non-potable environments, and reliable sealing performance in threaded iron piping assemblies. It is hex-headed for easy installation using standard pipe wrenches and rated for high working pressures per ASME B16.3.

Key Features

• ✅ Threaded Reduction – Female 4 inch NPT to male 3 inch NPT for direct sizing transitions
• ✅ Malleable Iron Construction – Durable under mechanical stress; ideal for steam, air, and gas systems
• ✅ Hex Head Design – Allows for torque application during installation without deformation
• ✅ Black Coating – Provides oxidation resistance during storage and service in low-moisture environments
• ✅ Pressure Rated – Suitable for use in systems up to 150 psi (steam) or 300 psi (non-shock water, oil, gas)

Technical Specifications

• Material: Malleable Iron (ASTM A197)
• Finish: Black Phosphate or Oil Coated
• Size: 4 inch Female Thread x 3 inch Male Thread (NPT)
• Standards: ASME B16.3, ANSI B1.20.1
• Working Pressure: 150 psi steam / 300 psi air, water, oil, gas (non-shock)

Common Applications

This 4 inch x 3 inch black hex bushing is typically found in fuel gas distribution, low-pressure steam lines, air compressor piping, and hydronic heating systems. It is a standard choice for size transitions in manifold installations, mechanical rooms, and equipment connections in both new construction and retrofit projects.

Installation Notes

Always use thread sealant or pipe dope rated for the intended system (e.g., gas-rated compound for fuel gas lines). Torque should be applied using a pipe wrench to the hex face, not the threads. Avoid overtightening to prevent thread distortion. This fitting is not intended for potable water systems.

Did You Know?

Black malleable iron fittings are preferred for natural gas piping over galvanized due to the risk of zinc flaking in fuel gas systems, which can clog regulators and burners.

Choose the 4 inch x 3 inch Black Iron Hex Bushing for applications that demand secure, threaded size transitions with mechanical durability. Trusted by professionals for decades, this fitting ensures long service life in pressure-rated black pipe installations.