Service Metal
300# Black Malleable Unions
- SKU:
- XBU
- Availability:
- Usually Ships Same Day
- Weight:
- 0.00 LBS
Description
300# Black Malleable Iron Union
300# Black Malleable Iron Unions are designed to connect two threaded pipe sections while allowing the joint to be disconnected for maintenance, repair, or equipment replacement without cutting the pipe.
Manufactured from durable malleable iron, these Class 300 unions provide strong, reliable performance in industrial, commercial, plumbing, mechanical, gas, air, oil, and compatible fluid piping applications where a serviceable threaded connection is required.
Product Highlights
- Three-piece threaded union design
- Female NPT x female NPT connections
- Allows piping sections to be disconnected without cutting pipe
- Designed for maintenance-friendly piping installations
- Useful near valves, pumps, equipment, and serviceable components
- Designed for higher-duty Class 300 threaded piping systems
- Durable black malleable iron construction
- Malleable castings conform to ASTM A197
- Malleable unions conform to ASME B16.39
- NPT threads conform to ASME B1.20.1
- Class 300 fittings are UL Listed
- Suitable for gas, oil, air, and compatible fluid piping systems
- Manufactured in an ISO-certified facility
- Country of origin: Thailand & China
Technical Specifications
| Product Type | Threaded Union |
|---|---|
| Material | Malleable Iron |
| Finish | Black |
| Pressure Class | 300# |
| Connection Type | Female NPT x Female NPT |
| Configuration | Three-Piece Union |
| Primary Function | Removable Threaded Pipe Connection |
| Casting Standard | ASTM A197 |
| Union Standard | ASME B16.39 |
| Thread Standard | ASME B1.20.1 |
| Listing | Class 300 Fittings are UL Listed |
| Manufacturing | ISO-Certified Facility |
| Country of Origin | Thailand & China |
Construction & Applications
Malleable Iron Construction
Manufactured from malleable iron castings conforming to ASTM A197 for dependable strength and durability in demanding threaded piping systems.
Three-Piece Union Design
The union uses two threaded end pieces joined by a central union nut, allowing the connection to be separated without rotating or cutting the adjoining pipe.
Class 300 Design
The heavier Class 300 construction is intended for more demanding threaded piping applications than standard Class 150 malleable iron fittings.
Why Use a Pipe Union?
Easier Maintenance
A union creates a convenient disconnect point in a threaded piping system, making it easier to service or replace valves, pumps, equipment, and other components.
No Pipe Cutting Required
The center union connection allows the piping to be separated without cutting pipe or disassembling long sections of the surrounding system.
Typical Applications
Industrial & Mechanical Piping
- Industrial piping systems
- Mechanical piping
- Compressed air systems
- Pump connections
- Valve installations
- Serviceable equipment connections
Common Service Applications
- Gas piping
- Oil piping
- Air lines
- Utility piping
- Compatible fluid systems
- Higher-duty threaded systems
Ask Willy: Need Pipe Size Help?
Use our common pipe diameters and wall thickness chart to confirm sizing before ordering 300# black malleable iron fittings. You can also review the union specification sheet and Certificate of Conformance below.
Standards & Approvals
ASTM A197
Malleable iron castings conform to ASTM A197.
ASME B16.39
Malleable unions conform to ASME B16.39, while NPT threads conform to ASME B1.20.1.
UL Listing
The supplied product information states that Class 300 malleable iron fittings are UL Listed.
Related Malleable Iron Standards
- Malleable fitting dimensions conform to ASME B16.3 where applicable.
- Malleable bushings, plugs, and locknuts conform to ASME B16.14.
- Malleable unions conform to ASME B16.39.
- NPT threads on applicable fittings conform to ASME B1.20.1.
- Class 300 fittings are UL Listed according to the supplied product information.
Need More 300# Black Malleable Iron Fittings?
Browse our complete selection of 300# black malleable iron fittings, including unions, tees, elbows, street elbows, couplings, bushings, and other heavy-duty threaded fittings.
Frequently Asked Questions
What is a 300# black malleable iron union used for?
It is used to connect two threaded pipe sections while providing a convenient disconnect point for future maintenance, repair, or equipment replacement.
What type of connections does this union use?
The union uses female NPT threaded connections on both ends.
How is a union different from a coupling?
A coupling creates a conventional threaded connection between two pipes. A union includes a separable center connection that allows the adjoining pipe sections to be disconnected without cutting them.
What does three-piece union mean?
The union consists of two threaded end pieces and a central union nut that draws the two sides together to form the connection.
Where are pipe unions commonly installed?
They are commonly installed near pumps, valves, meters, equipment, and other components that may require future service or replacement.
How is a 300# union different from a 150# union?
The Class 300 fitting is a heavier-duty fitting intended for more demanding threaded piping applications than a standard Class 150 fitting.
What standard applies specifically to malleable iron unions?
The supplied product information states that malleable unions conform to ASME B16.39.
What thread standard applies?
NPT threads conform to ASME B1.20.1.
Are Class 300 malleable iron fittings UL Listed?
Yes. The supplied product information states that Class 300 fittings are UL Listed.
What should I verify before ordering?
Confirm the nominal pipe size, connection type, required fitting class, service conditions, and applicable piping-system requirements before ordering.
Important Ordering & Installation Notes
- Confirm the required nominal pipe size before ordering.
- This union uses female NPT threaded connections on both ends.
- Install the union where future disassembly or equipment access may be required.
- Make sure both union halves are properly aligned before tightening the union nut.
- Malleable unions conform to ASME B16.39 according to the supplied product information.
- NPT threads conform to ASME B1.20.1.
- Confirm that Class 300 construction is appropriate for the intended piping system.
- Use compatible pipe, fittings, thread sealant, and accepted threaded installation practices.
- Depressurize and isolate the piping system before loosening or separating an installed union.
- Do not assume the “300#” class designation alone establishes allowable working pressure for every service condition.
- Verify pressure, temperature, media compatibility, applicable codes, and system requirements before installation.
- Refer to the specification sheet and Certificate of Conformance for additional product information.
