4 Inch Slip On Flange Stainless Steel

4 Inch Slip On Flange Stainless Steel

4-Inch Forged Stainless Steel Slip-On Flange (NPS 4 / DN100)

Category: Flanges | Sub-Category: Slip-On Flange / Hubed Plate Family

Core Features

  • 4-Inch Nominal Standard Sizing (NPS 4 / DN100): Precision-machined with a center clearance internal bore engineered to slide seamlessly over standard 4-inch nominal outer diameter (114.3 mm) stainless steel process pipelines, distribution headers, or fluid transport blocks.
  • Premium Forged Stainless Steel Core (ASTM A182): Hot-forged from certified austenitic stainless steel stock (typically available in low-carbon 304L or 316L grades). The hot-forging process refines the internal grain orientation and completely eliminates casting porosities, internal air pockets, and micro-voids, delivering an exceptionally high burst-pressure threshold under intense mechanical loading.
  • Low-Profile Slip-On (SO) Hub Profile: Features an integrated, low-profile raised hub or collar surrounding the center bore. This architecture distributes mechanical line strains, pipe-weight loads, and thermal expansion loops far more effectively than a standard hubless plate ring, making it highly resilient under localized system vibrations.
  • Double Fillet Weld Joint Security: Attached to the pipeline by sliding directly over the outer diameter of the 4-inch pipe. The joint is permanently secured via a robust double fillet weld matrix—one external weld tracking the perimeter of the hub neck and a secondary weld inside the bore.
  • Precision CNC Mating Face Sealing: Turned on automated multi-axis CNC lathes to achieve parallel joint alignment. Typically available in Raised Face (RF) or Flat Face (FF) configurations, finished with standardized micro-grooved phonographic or concentric serrations ( finish) to ensure maximum gasket mechanical friction and prevent fluid blowout under pressure surges.

At Kriloha Gaskets & Hardware, we recognize that mid-bore process networks require components that seamlessly balance robust mechanical security with standardized line flexibility. Our 4-Inch Forged Stainless Steel Slip-On (SO) Flanges represent our engineered answer for “High-Load-Joint-Security” and “Zero-Flexing-Integrity” across essential processing arrays. Sourced from our advanced automated fabrication facilities, Kriloha bridges the gap between raw material science and precise international dimensional standards, ensuring that every slip-on component integrates flawlessly alongside your high-performance sealing gaskets.

The engineering of our 4-inch stainless slip-on program is founded on Microstructural Uniformity and Deflection-Resistant Flatness. By forcing certified steel stock through controlled hot-forging paths rather than relying on lower-cost casting alternatives, we completely eliminate internal gas pockets, casting porosities, and structural micro-cracks. The refined metal grain structure smoothly traces the contour of the flange ring and low-profile hub, providing the component with an exceptional structural modulus. This allows it to withstand high bolt-torque demands across the standardized 8-bolt circle without warping or undergoing structural relaxation over time. Sourcing our premium Grade 304L provides standard hygienic protection and superior structural defense against atmospheric rust, while our premium Grade 316L stock introduces high Molybdenum and Nickel percentages to guard the critical sealing faces against localized crevice corrosion under the gasket matrix. At Kriloha, we precision-machine the sealing surfaces on advanced CNC vertical turning lathes, adding controlled concentric phonographic micro-serrations ( finish) that firmly anchor your chosen gasket matrix to eliminate fluid bypass or blowout risks.

Manufacturing and provisioning these critical flow-control connection pieces involves strict Dimensional Tolerance Checks, Volumetric Material Inspections, and Face Roughness Calibration. We collaborate directly with your project engineering, procurement, and facility maintenance teams to supply precise internal bores tailored to standard pipe outer diameters and unique wall-thickness schedules (such as Schedule 10S or Schedule 40S matching). By choosing Kriloha Gaskets & Hardware, you are investing in a “Future-Proof” industrial partnership that prioritizes your system’s lifetime reliability through superior stainless metallurgy and micro-tolerance engineering.

Primary Industrial Applications

  • Hygienic Process Pipelines: Clean-utility networks in food processing, large-scale industrial breweries, dairy plants, and pharmaceuticals where smooth, non-porous stainless steel prevents fluid contamination and survives clean-in-place (CIP) steam washdowns.
  • Chemical Processing & Reagent Transfer: High-reliability connection interfaces for industrial processing loops transporting volatile solvents, organic and inorganic acids, industrial reagents, and corrosive chemical waste.
  • Marine Infrastructure & Desalination: Critical, lifetime rust-resistant joints for seawater cooling networks, reverse osmosis water purification blocks, shipboard ballast loops, and coastal fuel manifolds exposed to heavy chloride environments (when specified in Grade 316L).
  • Moderate-Pressure Plant Utilities: Ideal for main factory utility headers distributing industrial water, low-pressure steam, compressed air loop arrays, cooling tower circuits, and non-corrosive gas piping operating under ANSI or metric parameters.
  • Modular Industrial Process Skids: Compact structural mounting flanges used by equipment manufacturers to link prefabricated mid-diameter piping manifolds directly to raised-face valves, strainers, inline instruments, and storage vessels.

Frequently Asked Questions (FAQs)

What is the structural difference between a Slip-On (SO) flange and a standard Flat Plate flange?

While both types slide over the pipe outer diameter and utilize double fillet welding, a standard plate flange is completely flat and collarless. A Slip-On flange features a low-profile raised hub or collar surrounding the center bore. This hub provides additional structural reinforcement at the weld zone, helping to distribute pipeline stresses and making it better suited for slightly higher mechanical loads or vibration profiles compared to a completely flat, hubless plate flange.

What are the standardized bolt hole configurations for a 4-inch Class 150 Raised Face flange?

According to the ASME B16.5 Class 150 standard, a 4-inch flange features an outer diameter of 9.00 inches (228.6 mm) and a bolt circle diameter of 7.50 inches (190.5 mm). It utilizes 8 bolt holes designed to accommodate 5/8-inch diameter bolts or stud bolts. (Note: Class 300 variants also utilize 8 bolt holes but feature a larger 7.88-inch bolt circle).

What specific welding configuration is required to install an ASME Slip-On flange?

A slip-on flange requires a standard double fillet weld setup for proper code-compliant installation:

One robust fillet weld around the exterior where the hub neck meets the outer diameter of the pipe wall.

A secondary fillet weld inside the bore, where the pipe end is slid back slightly (typically equal to the pipe wall thickness plus 3mm) from the flange face to prevent heat or weld spatter from damaging the machined sealing surface during field welding.

When should I select Grade 316L stainless steel over Grade 304L for this product?

Grade 304L is highly economical and excellent for freshwater processing, commercial HVAC loops, standard food-grade utilities, and clean factory environments. If your pipeline is handling aggressive chemical acids, highly concentrated salt brines, or is installed in an offshore marine environment exposed to heavy salt spray, upgrading to Grade 316L (which contains molybdenum) is recommended to prevent localized pinhole pitting.

Are Material Test Reports (MTRs) provided with these forged flanges from Kriloha?

At Kriloha Ltd., quality assurance is completely non-negotiable. Every shipment from our facility can be accompanied by comprehensive Material Test Reports (MTRs) confirming exact chemical compositions (including precise Carbon, Chromium, Nickel, and Molybdenum content where applicable), hardness values, yield/tensile strength data, and explicit compliance with international industrial standards to guarantee complete industrial traceability.

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