Threaded Flange – 4" Class 150 Raised Face (RF)

The 4" Class 150 Raised Face (RF) Slip-On Flange is a highly versatile, heavy-duty forged piping component designed to securely connect pipes, valves, pumps, and other essential equipment within low-to-moderate pressure industrial networks. Rated for Class 150 applications, this 4-inch flange provides a reliable, permanent connection that is easier to align and install than traditional weld-neck flanges, making it an incredibly cost-effective solution for standard fluid transfer systems.

Unlike weld-neck flanges that require a precision butt-weld, a slip-on flange is designed to literally "slip over" the outside of the pipe. Once properly aligned, the flange is secured using two fillet welds—one on the outside hub and one on the inside bore. This double-welded construction provides ample mechanical strength and leak-proof integrity for standard utility lines, cooling systems, and low-pressure processing environments, while allowing for slight inaccuracies in pipe cutting during the fabrication process.

This specific flange features a Raised Face (RF) profile. The sealing surface is machined to sit slightly higher than the bolting circle. When the bolts are tightened, this elevated face concentrates the mechanical pressure onto a smaller gasket area. This localized compression creates an exceptionally tight, high-integrity seal designed to contain liquids and gases safely, drastically reducing the risk of flange-face blowouts. Manufactured from premium forged steel, it conforms strictly to ASME / ANSI B16.5 standards.

Features & Benefits

• Slip-On Design: Slides easily over the pipe for rapid alignment and fit-up, significantly reducing fabrication time and lowering installation costs compared to weld-neck alternatives.

• Class 150 Pressure Rating: Engineered to safely handle low-to-moderate internal pressures, making it ideal for standard utility, water, and low-pressure hydrocarbon lines.

• Raised Face (RF) Profile: The elevated sealing face concentrates gasket compression, maximizing seal integrity and eliminating the risk of leaks under operational vibration.

• Double Fillet Weld Securement: Designed to be welded on both the inner diameter and the outer hub, ensuring structural rigidity and dependable fluid containment.

• ASME B16.5 Compliant: Machined to strict industry tolerances to guarantee a perfect face-to-face fit with standard mating equipment and piping networks.

Specifications & Technical Details

Applications

This 4-inch Class 150 RF slip-on flange is a highly adaptable component used extensively across surface operations and industrial facilities. Typical applications include low-pressure water and fluid transfer manifolds, cooling water lines, standard mud tank piping, compressed air networks, pump suction headers, and general oilfield routing where severe high pressure is not a primary factor.

Quality Assurance

All our industrial flanges are manufactured from premium forged steel and subjected to strict quality control processes. Each slip-on flange undergoes rigorous dimensional inspection, precision face machining verification, and non-destructive testing (NDT) to ensure absolute structural integrity and defect-free sealing surfaces. Full material test reports (MTRs) are available upon request to guarantee full compliance with ASME and ANSI industry standards.

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