Pioneer Industries is an internationally renowned manufacturer and exporter of Brass Flare Unions, engineered to connect two 45° flared tubing lines in-line with an impenetrable metal-to-metal seal in high-pressure refrigeration, HVAC, and pneumatic piping circuits.
The Brass Flare Union manufactured by Pioneer Industries is a high-integrity in-line tube coupling fitting designed to join two lengths of 45° flared copper, brass, or aluminum tubing. Featuring two opposing precision-machined 45° SAE male flare cones separated by a central hexagonal wrench flat, this fitting provides an ultra-reliable, full-flow connection between tubing segments without requiring brazing, soldering, or open flames.
Manufactured strictly in accordance with SAE J512, SAE J513, and ASME B16.26 standards, our flare unions are precision-turned from extruded high-tensile brass bar stock (BS 249 / CW614N / ASTM B16 C36000) or hot-forged brass blanks (BS 218 / CW617N). The dense, micro-grain brass microstructure eliminates wall porosity and withstands severe hydraulic pulsation, thermal expansion cycles, and mechanical vibration.
Pioneer Industries exports Brass Flare Unions to commercial refrigeration contractors, HVAC manufacturers, automotive builders, and industrial gas distributors across more than 85 countries worldwide. With massive inventory stocks in Mumbai, India, we provide rapid international dispatch on standard fractional inch and metric configurations.
Every union is manufactured under an ISO 9001:2015 certified quality management system using high-precision CNC multi-axis machines. Thread concentricity, cone surface finish, and orifice diameters are 100% verified. Dispatched consignments are accompanied by EN 10204 Type 3.1 material test certificates.
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In refrigeration line-set installation, field repairs, and industrial machinery piping, extending tubing runs or coupling prefabricated coils requires an ultra-reliable in-line joint. Pioneer Industries’ Brass Flare Union provides an impenetrable metal-to-metal wedge seal on both ends when drawn down by standard SAE flare nuts. The joint creates a completely smooth internal flow path that minimizes pressure drops and prevents oil trapping in refrigeration suction lines.
Because the union requires zero soldering flux or brazing heat, there is zero risk of internal copper oxidation (scale) entering the system, protecting sensitive compressor valves and expansion devices from premature contamination failure. Operating reliably across temperatures from -54°C to +121°C, it is fully rated for pressures up to 5,000 PSI.
Pioneer Industries manufactures Brass Flare Unions in standard fractional sizes from 1/8" to 3/4" tube OD, with reducing union combinations available upon request. Working pressures up to 5,000 PSI (345 bar). Complies with SAE J512, SAE J513, ASME B16.26, and ASTM B16 specifications.
Explore comprehensive engineering dimensional configurations for Fractional Inch Series, Metric Series, and Certified Material Specifications. Manufactured according to SAE J512, SAE J513, ASME B16.26, and international standards.
| Part No. | Tube O.D. (T) | Both Flare Threads (UNF) | Hex Size (F) | Overall Length (L) | Orifice Dia (E) | Weight (approx) | Working Pressure |
|---|---|---|---|---|---|---|---|
| PI-FU-02 | 1/8" | 5/16-24 UNF | 3/8" | 0.94" | 0.078" | 18 g | 5,000 PSI |
| PI-FU-03 | 3/16" | 3/8-24 UNF | 7/16" | 1.06" | 0.125" | 24 g | 5,000 PSI |
| PI-FU-04 | 1/4" | 7/16-20 UNF | 7/16" | 1.19" | 0.188" | 34 g | 5,000 PSI |
| PI-FU-05 | 5/16" | 1/2-20 UNF | 1/2" | 1.31" | 0.219" | 46 g | 4,500 PSI |
| PI-FU-06 | 3/8" | 5/8-18 UNF | 5/8" | 1.50" | 0.281" | 68 g | 4,000 PSI |
| PI-FU-08 | 1/2" | 3/4-16 UNF | 3/4" | 1.75" | 0.406" | 110 g | 3,500 PSI |
| PI-FU-10 | 5/8" | 7/8-14 UNF | 7/8" | 2.00" | 0.500" | 162 g | 3,000 PSI |
| PI-FU-12 | 3/4" | 1-1/16-14 UNS | 1-1/16" | 2.25" | 0.625" | 250 g | 2,500 PSI |
| Part No. | Tube O.D. (mm) | Thread Profile (UNF) | Hex Size (mm) | Overall Length (mm) | Orifice Dia (mm) | Weight (g) | Working Pressure (bar) |
|---|---|---|---|---|---|---|---|
| PI-FU-M06 | 6 mm | 7/16-20 UNF | 11 mm | 30.2 mm | 4.8 mm | 34 g | 345 bar |
| PI-FU-M08 | 8 mm | 1/2-20 UNF | 13 mm | 33.3 mm | 5.6 mm | 46 g | 310 bar |
| PI-FU-M10 | 10 mm | 5/8-18 UNF | 16 mm | 38.1 mm | 7.1 mm | 68 g | 276 bar |
| PI-FU-M12 | 12 mm | 3/4-16 UNF | 19 mm | 44.5 mm | 10.3 mm | 110 g | 241 bar |
| PI-FU-M16 | 16 mm | 7/8-14 UNF | 22 mm | 50.8 mm | 12.7 mm | 162 g | 206 bar |
| PI-FU-M18 | 18 mm | 1-1/16-14 UNS | 27 mm | 57.2 mm | 15.9 mm | 250 g | 172 bar |
| Component | Material Specification | Standard Specification | Chemical Composition | Mechanical Properties | Temperature Limits | Key Features |
|---|---|---|---|---|---|---|
| Precision Extruded Union Body | Forging Brass (BS 218 / CW617N) | BS EN 12165 / ASTM B283 C37700 | Cu: 57.0–59.0%, Pb: 1.6–2.5%, Zn: Rem. | Tensile ≥ 440 MPa, 110–150 HB | -54°C to +121°C | Contoured grain flow, dense wall structure, zero porosity, high shock resistance |
| SAE 45° Male Flare Cones | Free Cutting Brass (BS 249 / CW614N) | IS 319 Gr. 1 / ASTM B16 C36000 | Cu: 58.0–60.0%, Pb: 1.5–3.0%, Zn: Rem. | Tensile ≥ 400 MPa, 100–140 HB | -54°C to +121°C | Precision CNC machining, exact 45° cone angle, micro-inch surface finish |
| SAE Flare Nut | Extruded Brass / Forged Brass | SAE J512 / SAE J513 / ASTM B16 | Cu: 58.0–61.0%, Zn: Rem. | Tensile ≥ 380 MPa | -54°C to +121°C | Short and long skirt options, internal 45° beveled shoulder for tube support |
| Tubing Interface | Flared Copper / Brass Tube | ASTM B88 / ASTM B280 / ASTM B135 | Cu ≥ 99.9% (DHP) | Soft Annealed Temper | -54°C to +121°C | 100% metal-to-metal seal, zero elastomeric degradation in refrigerants/LPG |
Brass Flare Union fittings find deployment across demanding thermal, fluid, and gas piping circuits:
Joins two sections of copper line set during HVAC installations or field line extensions.
Connects evaporator and condensing unit piping runs across long industrial runs.
Provides safe, mechanical in-line couplings on copper gas delivery lines.
Couples hydraulic brake and power steering copper-nickel lines on commercial vehicles.
Connects rigid copper air distribution lines across automated factory machinery.
Joins refrigerant lines across cabin bulkheads on buses, trucks, and rail cars.
Connects centralized oil delivery tubing lines on heavy production machinery.
Couples flared copper-nickel seawater cooling tubes on marine engine heat exchangers.
Pioneer Industries’ Brass Flare Union are widely used in numerous industries like:
Expert engineering insights and technical guidance regarding design specifications, pressure tolerances, flare cone sealing mechanics, tubing compatibility, and installation best practices for industrial Brass Flare Union.
A Brass Flare Union is an in-line tube fitting featuring two opposing 45° SAE male flare cones with a central hex wrench flat. Its primary function is to couple two lengths of 45° flared copper or brass tubing together in a straight, leak-tight line without requiring soldering or brazing.
The union relies on an all-metal 45° mechanical compression seal. Flared copper tube ends are placed over each male cone, and flare nuts are threaded onto the union threads. Tightening the nuts compresses the copper flares against the brass cones, creating a hermetic metal-to-metal wedge seal.
Standard flare unions have equal sizes on both ends (e.g. 3/8" x 3/8"). However, Pioneer Industries also manufactures Reducing Flare Unions (e.g. 1/2" x 3/8", 3/8" x 1/4") to connect two tubes of different outside diameters directly.
No. The threads on a flare union are straight mechanical UNF threads designed exclusively to generate axial clamping force. Sealing occurs entirely on the 45-degree cone faces. Tape or liquid sealant must never be applied to flare threads.
Depending on nominal tube size, working pressure ratings range from 2,500 PSI (172 bar) for 3/4" tubing up to 5,000 PSI (345 bar) for 1/4" tubing, with a minimum 4:1 hydrostatic burst safety factor.
Yes. Flare unions can be loosened and reassembled multiple times without degradation of sealing integrity, making them ideal for systems requiring routine filter replacement, maintenance, or line re-routing.
Always use two wrenches: one open-end wrench to hold the central hexagonal body of the union stationary, and a second wrench to torque the flare nut. Never tighten one nut against the opposite nut.
Our unions are precision-machined from BS 249 / CW614N (ASTM B16 C36000) extruded brass bar stock, providing high tensile strength (above 400 MPa), exceptional machinability, and superior corrosion resistance.
Yes. Pioneer Industries’ Brass Flare Unions are fully rated for high-pressure synthetic refrigerants including R-410A, R-32, R-404A, and R-134a across continuous operating temperatures from -54°C to +121°C.
Pioneer Industries provides EN 10204 Type 3.1 Mill Test Certificates verifying chemical composition, mechanical properties, and 100% pneumatic bubble leak testing under water.
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