Flange Fittings

What Are Flange Fittings?

Flange fittings are the connection of choice when lines are too large, too high-pressure, or too vibration-prone for threaded connections. The flange head carries an O-ring in a face groove. A split flange (clamp) pulls the head flat against the matching port; the O-ring does the sealing — not the screws.

Three components complete every connection:

• Flange head (on the hose tail): the machined face with the O-ring groove
• O-ring: the actual seal, sized for the flange code
• Split flange and screws: the halves and four screws that clamp the head in place

That is why flanges dominate high-pressure, large-bore circuits: no thread to gall, a compact envelope, and a seal that survives repeated assembly.

Core value: match size and code, and a flange connection holds rated pressure with zero leakage; mismatch them, and nothing clamps.

Three customer paths:

• For OEM manufacturers — standardize Code 61 or Code 62 ports and lock in repeatable assembly quality.
• For end users and maintenance teams — identify whether the failed connection is Code 61, Code 62, or an equipment style, then order the right replacement the first time.
• For distributors — consolidate flange and threaded families in one catalog, with sample kits and private labeling.

Key Specifications

Connection-Side: Flange Size and Code Chart

Every flange order starts with two checks: the nominal size and the code. The dash number states the nominal size in 1/16 in steps (dash 16 = 1 in). The table below lists the flange sizes we supply.

Code 61 and Code 62 heads have different outside diameters, head thicknesses, and screw sizes, so the two codes are never interchangeable. International equivalents: ISO 6162-1 for Code 61 and ISO 6162-2 for Code 62; we also match DIN and other national flange patterns on request.

Hose-Side: Matching Ferrule Series

The hose end of our flange fittings is matched to a hose family and ferrule series, sized for large-diameter, high-pressure constructions: 2SN, 4SP/4SH, R12, and PTFE.

Assembly working pressure follows the hose family and the flange code, whichever is lower. Confirm the final value against your hose data sheet and our engineers.

Materials, Seals, and Finish

Key Features

• SAE J518 Code 61/62 flange heads; ISO 6162 equivalents available
• O-ring face seal: no threads to gall, no sealant to fail
• Sizes 1/2-4 in with matched split flanges, screws, and O-rings
• Straight and 90° configurations for tight routing
• Matched hose-tail and ferrule sets for leak-free crimped assemblies

Crimping and Installation

The hose end of every flange fitting is crimped with standard hydraulic crimping machines and common die sets. We provide reference crimp data and die selection for your machine model with every order.

Crimp-side steps:

1. Cut the hose square.
2. Prepare the hose end per the maker’s instructions; skive where required (4SH, R12).
3. Insert the stem fully into the hose bore.
4. Slide the ferrule on and seat it against the stem shoulder.
5. Crimp with a hydraulic hose crimping machine to the target crimp diameter from the hose maker’s chart.
6. Verify the crimp O.D. with a caliper and record the value.

Flange connection-side rules:

• Inspect the O-ring groove and the port face; a scratch or chip causes leakage.
• Fit the O-ring, seat the head on the port, and install the split flange and four screws.
• Tighten evenly in a cross pattern, in two passes.
• Replace the O-ring whenever the assembly is opened.
• Never mix Code 61 and Code 62 halves or heads; dimensions differ.

Nomenclature: How Flange Sizes Are Designated

Flange descriptions state nominal size, code, and configuration. Learn these fields and you can read any flange description:

A typical description reads: 1-1/2 in SAE Code 62 flange head x 1-1/2 in hose, straight. We assign the exact part number, split flange, screw set, and O-ring on request — send flange size, code, hose family, and dash, and our engineers confirm the set before you order.

Matching and Identification

Equipment-style flanges look alike, so measure first. Three dimensions identify a flange: head thickness, head O.D., and bolt-hole center distance. Use this table as the first filter:

If you can identify SAE flange fittings by measuring, order with confidence; if not, send photos with a ruler in the frame and we identify size, code, and matching set free of charge.

Applications and Industries

Flange fittings are standard where threaded connections reach their limits:

• Mining and tunneling equipment
• Construction and mobile machinery
• Oil and gas, offshore, and marine systems
• Steel mills and heavy industrial presses
• Injection molding machines
• Hydraulic power units with large flow lines
• Forestry and material handling

Operating range follows the hose: rubber assemblies typically run from -40 °C to +100 °C (R12 to +121 °C); PTFE assemblies from -70 °C to +260 °C at the core.

Ordering and Packaging

• Unit of measure: sold per piece (EA), packed in boxes per size
• MOQ: one box per size; mixed-size sample kits available
• Supplied as a set: flange head, split flange, screws, and O-ring, or loose components on request
• Customization: Code 61/62, straight or elbow, stainless steel, special compounds, private labeling
• Export packing: corrugated cartons with moisture barrier for sea freight

Flange Connection FAQ

Can Code 61 and Code 62 flanges be mixed? No. The two codes have different head dimensions, screw sizes, and pressure ratings. A Code 62 head will not clamp with Code 61 halves, and mixing them risks leakage or failure.

How do I confirm a flange fitting matches my hose? Three checks: confirm the flange size and code against the port (or measure the head), match the dash size to the hose I.D., and confirm the hose construction against the ferrule series table. Send us both measurements and we verify the full set.

Carbon steel or stainless steel — which do I need? Zinc-plated carbon steel suits standard hydraulic service. Stainless steel flange fittings suit corrosive chemicals, offshore, food, and hygienic environments. Brass is not a standard flange material for hydraulic service.

What is the difference between Code 61 and Code 62? Code 61 is rated 3,000 to 5,000 psi by size. Code 62 is the high-pressure class, rated 6,000 psi through 2-1/2 in, with a thicker head and larger screws.

How do I identify the flange size and code? Measure the head thickness, head outside diameter, and bolt-hole center distance, then compare with the code chart. Head thickness alone separates Code 61 from Code 62 in most cases.

How should flange screws be tightened? Tighten the four screws evenly in a cross pattern, in two passes. The O-ring does the sealing; the screws only hold the head flat.

Do flange fittings need an O-ring or sealant? They seal with an O-ring in the face groove, never with thread sealant. Replace the O-ring each time the connection is opened (NBR standard; FKM and others on request).