1/4 inch Square Head Black Cast Iron Plug

BLK CI Plug – 1/4" Square Head, Threaded Iron for System Closure

The BLK CI PLUG SQ HD 1/4" VBGF 7670 is a black cast iron pipe plug with a square head, designed for sealing the end of female-threaded iron pipe or fittings. Manufactured to meet industry-standard tolerances, it provides a mechanical closure for low- to moderate-pressure piping systems in commercial, industrial, and utility-grade applications.

This plug is cast from malleable iron and finished in black oxide, making it suitable for use in systems where corrosion resistance from external coatings is not required. Its tapered NPT threads ensure secure engagement and sealing under typical service loads, and the square head enables easy installation and removal using standard tools.

Key Performance Attributes

• ✅ Material: ASTM A197 malleable cast iron with black finish
• ✅ Connection Type: 1/4" Male NPT – tapered for pressure-rated threaded engagement
• ✅ Head Type: Square head for wrench-driven installation and extraction
• ✅ Corrosion Tolerance: Suitable for interior use in gas, steam, air, or non-potable water systems
• ✅ Temperature & Pressure Rating: In accordance with ASME B16.3 limits for malleable iron fittings

Installation Considerations

Apply compatible thread sealant or PTFE tape on male threads prior to assembly. Avoid overtightening to prevent thread deformation or fitting damage. Use a wrench or socket on the square head for precise torque application. This plug is not suitable for use in potable water systems unless otherwise certified for such use.

Typical Applications

Commonly used to seal unused ports in piping networks, equipment tappings, drain valves, or test ports. Ideal for natural gas lines, air compressor systems, steam piping (within rated pressure limits), and mechanical pipe closures in boiler rooms or utility installations. Appropriate for new construction and retrofits involving black iron piping.

Standards and Compliance

• Manufacturing Standard: ASME B16.3
• Thread Standard: ANSI/ASME B1.20.1 (NPT)
• Material Spec: ASTM A197 for malleable iron castings

Material Note

Malleable cast iron fittings provide excellent dimensional stability and mechanical strength. The black finish is suited for dry or non-corrosive environments and supports mechanical systems where galvanized coatings are not required.

The BLK CI PLUG SQ HD 1/4" is a compact and dependable closure fitting for contractors working with threaded iron piping. Its form factor, thread compatibility, and structural integrity make it an essential component for maintaining system integrity in closed-end service conditions.