ASTM A182 F304 / F304L Slip-On Flange (SORF)
ASME B16.5 Stainless Steel Slip-On Flange
ASTM A182 F304 / F304L slip-on flanges (SORF) are forged austenitic stainless steel flanges designed for easy installation and accurate pipe alignment in pressure piping systems.
Manufactured in accordance with ASME B16.5, these flanges slip over the pipe and are welded on both the inside and outside, providing reliable strength for low to medium pressure applications.
The F304L low-carbon grade offers improved weldability and resistance to intergranular corrosion, making it especially suitable for welded stainless steel piping systems.
What Is ASTM A182 F304 / F304L?
ASTM A182 is a material specification covering forged or rolled alloy and stainless steel flanges for pressure service.
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F304: Standard austenitic stainless steel with good corrosion resistance and mechanical strength
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F304L: Low-carbon version of F304, designed to reduce the risk of carbide precipitation after welding
For most welded applications, ASTM A182 F304L is preferred.
Equivalent Grades
Equivalent Grades:
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN |
| F304 | 1.4301 | S30400 | SUS 304 | 304S31 | 08Х18Н10 | Z7CN18‐09 | X5CrNi18-10 |
| F304L | 1.4306 / 1.4307 | S30403 | SUS 304L | 3304S11 | 03Х18Н11 | Z3CN18‐10 | X2CrNi18-9 / X2CrNi19-11 |
Chemical Composition
| Steel Grade | C(Max) | Si(Max) | Mn(Max) | P(Max) | S(Max) | Ni | Cr | N |
| F304 | 0.08 | 0.75 | 2.00 | 0.045 | 0.03 | 8.0–10.5 | 18.0–20.0 | 0.1 |
| F304L | 0.03 | 0.75 | 2.00 | 0.045 | 0.03 | 8.0–12.0 | 18.0–20.0 | 0.1 |
Mechanical Properties
| Grade | Tensile Strength (MPa) min | Yield Strength 0.2% Proof (MPa) min | Elongation (% in 50mm) min | Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| F304 | 515 | 205 | 40 | 92 | 201 |
| F304L | 485 | 170 | 40 | 92 | 201 |
Slip-On Raised Face (SORF) Design
Slip-on flanges are designed to slip over the pipe and are welded at both ends, providing:
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Easy installation and alignment
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Lower cost compared with weld neck flanges
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Adequate strength for moderate pressure service
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Compatibility with raised face (RF) gasket surfaces
Dimensions & Standards
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Material Standard: ASTM A182 / ASME SA182
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Flange Standard: ASME B16.5
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Facing: SORF (Raised Face)
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Pressure Classes:
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Class 150
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Class 300
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Class 600
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Class 900
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Class 1500
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Class 2500
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Size Range: 1/2″ – 24″
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Manufacturing Process: Forged
Inspection & Quality Control
ASTM A182 F304 / F304L slip-on flanges are supplied with comprehensive inspection and testing, including:
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Chemical composition analysis
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Mechanical property testing
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PMI (Positive Material Identification)
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Dimensional inspection
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Visual examination
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Certification: EN 10204 3.1
ASTM A182 F304 / F304L Slip-On Flanges (SORF) manufactured to ASME B16.5 provide a cost-effective and reliable solution for stainless steel piping systems.
With excellent corrosion resistance, good weldability, and easy installation, these flanges are widely used in a broad range of industrial applications.
ASTM A182 F304-F304L-Slip-On FlangeA SME B16.5
