Brass Inverted Flare 45 deg Male Elbow

A Brass Inverted Flare 45 deg Male Elbow is a specialized heavy-duty hydraulic and fuel fitting conforming to SAE J512 and SAE J1231 standards. Unlike standard flare fittings that feature external male cones, an inverted flare fitting houses an internal female 42°/45° conical seat recessed inside the fitting body cavity with straight internal UNF threads. The opposing port features an external tapered male NPT or NPTF dryseal pipe thread angled at a 45-degree sweep. When a male-threaded inverted flare nut draws the double-flared tube against this internal seat, it generates a high-pressure, impenetrable metal-to-metal wedge seal completely enclosed and protected from road debris, mechanical impact, and vibration fatigue.

A 45-degree elbow provides a much gentler directional sweep than a right-angle 90-degree turn, significantly reducing flow restriction, fluid turbulence, and hydraulic pressure loss (lower equivalent length-to-diameter ratio, Le/D). This hydraulic advantage is critical in high-viscosity fluid lines such as automotive power steering return circuits, automatic transmission oil cooler lines, and high-velocity fuel delivery systems. Additionally, the 45-degree angle permits sleek diagonal piping trajectories along vehicle chassis rails, firewall corners, and tight engine mountings where 90-degree routing would require excessive offsets.

The core difference lies in the location of the sealing seat and the thread gender. In standard 45° flare fittings (SAE J513), the fitting body has external male threads and an exposed protruding male cone, and uses a female-threaded nut. In inverted flare fittings (SAE J512), the body features internal female straight threads and a recessed internal female seat, into which a male-threaded nut is screwed. This inverted geometry provides a vastly more compact physical envelope, shields the delicate sealing cone from nicking or damage during handling, and offers superior resistance to blow-out under severe pressure surges.

Double flaring folds the tube wall backward onto itself before forming the 45-degree sealing cone, creating a reinforced dual-thickness lip. This extra wall thickness is mandatory for bundy-welded steel lines, copper-nickel brake tubes, and rigid hydraulic tubing operating at elevated pressures (up to 2,800 PSI). Single flaring thin-wall rigid tubing often results in edge splitting, uneven seating, or circumferential thinning during final torque makeup, whereas double flaring provides the mechanical ductility and bulk required for positive, leak-free compression against the internal inverted seat.

Pioneer Industries manufactures Brass Inverted Flare 45 deg Male Elbows in strict compliance with SAE J512 (Automotive Tube Fittings), SAE J1231, and ASME B16.26. The internal inverted flare ports utilize Unified National Fine (UNF) Class 2B straight female threads (such as 3/8-24, 7/16-24, 1/2-20, and 5/8-18). The male pipe threads conform to ANSI/ASME B1.20.1 (NPT) or SAE J476 Dryseal (NPTF), ensuring universal compatibility with automotive master cylinders, fuel pumps, carburetors, and transmission casings.

Our Brass Inverted Flare 45 deg Male Elbows are rated for working pressures up to 2,800 PSI (approx. 193 bar) for 1/8″ to 3/8″ tube OD, and up to 1,500 to 2,000 PSI (approx. 103 to 138 bar) for larger 1/2″ and 5/8″ sizes, backed by an engineered certified 4:1 hydrostatic burst safety factor under ASME B31.3. The continuous operating temperature range spans from -54°C to +121°C (-65°F to +250°F), making it impervious to engine bay thermal radiation, exhaust proximity heat, and sub-zero winter ambient conditions.

This fitting is fully compatible with seamless or bundy-welded low-carbon hydraulic steel tubing, Copper-Nickel (Cupro-Nickel 90/10) brake line tubing, soft annealed copper tubing (ASTM B88), seamless brass tubing, and bendable automotive aluminum alloys. The tubing must be annealed to allow 45° single or double flaring without micro-cracking.

The male NPT end seals along tapered thread flanks through mechanical wedging. Apply an approved anaerobic PTFE paste sealant or fuel-certified PTFE tape to the male pipe threads only. Thread the fitting into the female port finger-tight, then rotate it with an open-end wrench 2 to 3 full turns until the inverted flare port points in the exact trajectory required for the incoming tubing. Never loosen the elbow to achieve angular alignment, as doing so breaks the thread seal. Keep the internal inverted flare cavity completely free of thread tape and sealant.

Yes. The inverted flare mechanical seal does not crimp or permanently deform the fitting body, allowing unlimited disassembly and reassembly during brake component changes, transmission servicing, or fuel filter replacements. When reconnecting, inspect the tube double flare for scoring, cracks, or excessive flattening. If the flare is damaged, trim the tube and reform a fresh double flare to ensure 100% leak-free sealing.

Pioneer Industries hot-forges these elbows from high-tensile BS 218 / CW617N (ASTM B283 C37700) forging brass, composed of 57–59% Copper, 1.6–2.5% Lead, and remainder Zinc, achieving tensile strength exceeding 440 MPa and zero micro-porosity. Every batch undergoes 100% pneumatic underwater bubble testing, optical comparator profile checking of the 42°/45° internal cone seat, and thread pitch gauge verification. Shipments are supplied with authentic EN 10204 Type 3.1 Mill Test Certificates.