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Slip On Flange
Slip on flange, also called SO flange. It's a kind of flange slides over the pipe with internal design is slightly larger than the pipe. Since the inner diameter of the flange is slightly larger than the outer diameter of the pipe, the SO flange can be directly connected to equipment or pipe by fillet weld at the top and bottom of the flange.

product description


Slip-on flange, also known as SO flange. It is a flange that slips over a pipe and is designed to be slightly larger than the pipe internally. Since the inside diameter of the flange is slightly larger than the outside diameter of the pipe, the SO flange can be connected directly to the equipment or pipeline through fillet welds at the top and bottom of the flange. It is used to insert the pipe into the flange.

Dimensions and Pressure Ratings

Standard: ASNI/ASTMB16.5 / 16.36/16.47A/16.47B B2220 – 2001, DIN2527/2636/2637/2638/2566/2576/2633/2635/2642/2653/2655.

Pressure Rate: 150LBS to 2500LBS / PN10 to PN400

Dimension: 1/2" to 48"

Material: Carbon steel, Alloy Steel, Stainless steel.

Sealing type: RF, FF, MFM, TG,RTJ

Slip on Neck (SO)

Pressure rating:
class 150LBS、300LBS、400LBS、600LBS、900LBS、1500LBS、2500LBS
ANSI B16.5, ANSI B16.47, MSS SP44, ANSI B16.36, ANSI B16.48, API 605, AWWA AND DRAWING
· CS
Standard: ASTM / ASME A/SA 105 / 350 LF 2
· SS
Standards: ASTM / ASME A/SA 182
Steel Grade: F 304, 304L, 304H, 309S, 309H, 310S, 310H, 316, 316TI, 316H, 316L, 316LN, 317, 317L, 321, 321H, 347, 347H, 904L.
· AS
Standard: ASTM / ASME A/SA 182
ASTM A182 F1, F11, F12, F22, F5, F9, F91.
· Nickel Alloy
Standard: ASTM / ASME SB 564 / 160 / 472
Grade: UNS 2200 (NICKEL 200), UNS 4400 (MONEL 400), UNS 8825 INCONEL (825), UNS 6600 (INCONEL 600), UNS 6601 (INCONEL 601), UNS 6625 (INCONEL 625), UNS 10276 (HASTELLOY C 276), UNS 2201 (NICKEL 201), (ALLOY 20 / 20 CB 3)

Threaded (TH)

Types of Slip On Flange Welding

SO flanges can be divided into SO welded plate flanges and SO welded steel pipe flanges with necks. Its mechanical characteristics between the whole flange and ring flange. The structure is simple and easy to process. Therefore, flat welding flanges are widely used in various fluid pipelines.

According to different face types, there are also a series of convex face type and ring joint face type.

Raised Face Slip On Flange

Sliding flanges have a small portion protruding from the bottom surface, and this type is the raised face sliding flange. The purpose of this area is to place a gasket seat during installation for better sealing performance. 

The height of this convex surface increases as the pressure rating increases.

RTJ Slip On Flange

A small groove is machined in the convex part, this form is known as RTJ type, the function of this groove is to place the gasket and also used for sealing, RTJ is designed for high pressure use as compared to RF type.

Manufacturing Types

Slip On Flange can be manufactured by forging, steel cutting and casting. Among these manufacturing types, forged type is the best in quality and most popular in use, but the price is higher than other types. That's why it's important that you understand what the specific work environment is before purchasing a Slip On Flange.

Slip On Flange Benefits

Reduced installation costs

Easier alignment with other components during installation

Better leak-proof performance

Inside and outside flange welding

Less time required to accurately cut pipe

Compatible with lower hubs on sliding flanges because the pipe slides on the flange

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Threaded (TH)

Threaded (TH)

Threaded (TH)


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