Slip-On flanges slide over the pipe and are fillet-welded on both sides — lower cost than WN, suitable for moderate-pressure piping.
Slip-On (SO) flanges are circular discs with a bore slightly larger than the pipe outer diameter. The flange slips over the pipe end and is fillet-welded on both sides (front and back). They are simpler to fabricate and lower cost than WN flanges, and the pipe does not need a precise square cut to length. SO flanges are NOT suitable for high-pressure critical service, high-temperature cycling or significant bending stress.
SO flanges are rated for moderate pressure — up to Class 150 and Class 300 in ASME B16.5. They are commonly selected where cost and ease of assembly are priorities over maximum pressure rating. Supply is reviewed per inquiry against standard, pressure class, NPS, grade and facing.
Reviewed against your required standard, pressure class and nominal pipe size.
ASME B16.5 is the primary standard for SO flange dimensions and pressure-temperature ratings. Regional standards such as EN 1092-1, JIS B2220 or DIN 2500 can be reviewed per inquiry.
Class 150 and Class 300 are the most common SO flange ratings in ASME B16.5. Actual pressure-temperature suitability depends on operating temperature — higher temperatures derate the flange. Confirm your operating conditions at inquiry.
Industry Standard: NPS ½ through NPS 24 per ASME B16.5.
Custom Manufacturing: Larger sizes (above NPS 24) custom evaluated per forging capacity.
Actual Supply Availability: Confirmed per inquiry against grade, schedule and pressure class.
Moderate-pressure connections in corrosion-resistant titanium piping.
Titanium flange connections in desalination and water treatment systems.
Secondary-side connections and auxiliary piping on titanium heat exchangers.
SO flanges are most commonly supplied in ASME B16.5 Class 150 and Class 300. Class 400 and higher are less common and should be evaluated per inquiry.
SO flanges are lower cost and easier to fabricate — the pipe does not require a precise square cut. They are selected for moderate-pressure, non-critical services. WN flanges have a hub that distributes stress more effectively and are preferred for high-pressure, high-temperature or critical service where joint integrity is paramount.
RF (Raised Face) is the standard facing for SO flanges per ASME B16.5. FF (Flat Face) is available per request and is typically used with full-face gaskets. RTJ (Ring Type Joint) is uncommon on SO flanges and should be evaluated per inquiry.
Please specify the standard (e.g., ASME B16.5), pressure class (e.g., Class 150), nominal pipe size (NPS), grade, facing (RF / FF) and quantity. We will confirm availability and supply conditions. For drawing-based or custom requirements, you may share your drawings with our sales team by email or WhatsApp after initial contact. Include material grade, dimensions, tolerances, quantity and drawing reference.
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