Blind Flange
Solid blank flanges for pipeline isolation, shutdown and maintenance, available in carbon steel, stainless steel and alloy steel per international standards.
Slip-on flanges (SO) feature a simple slip-over design, welded inside and outside for secure connections. Ideal for low-to-medium pressure applications and general industrial piping.
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. It is used to insert the pipe into the inner hole of the flange. Slip-On Pipe Flanges. As made obvious by their name, these pipe flanges slip over the pipe. They're manufactured with an inside diameter that is slightly bigger than the pipe's outside diameter. These attachments are connected to the pipe via fillet weld at the top and bottom of the flange.
The SO flange can be divided into SO welding plate flange and SO welding hubbed steel pipe flange. Its mechanical characteristics are between the integral flange and the looping flange. The structure is simple, and the processing is convenient. So slip on flange welding is widely used in various fluid pipelines.
Depends on different face, there are also ranges raised face type and ring type joint face type.
There is a small portion extruded from the bottom face of the slip on flange, this type is raised face slip on flange. The function of this area is to place a gasket seat during installation to get a better sealing performance.
As the pressure ratings bigger, the height of this raised face will be bigger.
A small grooved is machined on the raised face part, this form is called RTJ type, the function of this groove is to place the gasket ring, also applied for sealing, compared to RF type, RTJ is designed for high pressure use.
Slip on flange use slip welding to connect equipment, so either below of name is describing the same flange:
Slip on flange can be made by forging, steel cutting, casting and etc. Among these manufacturing types, the forging type gains the best quality and also the most common use, price is higher than other types. So before purchase the slip on flange, you have to know what is the specific working environment.
Slip-On flanges or SO flanges are commonly lower in price than weld-neck flanges, and to this effect are a popular choice for our customers.
Slip on flange are usually cheaper than Weld-Neck flange (welding neck flange), which is why many customers prefer to choose them. It is one of the commonly used flanges for low pressure, medium temperature piping system.
On the other hand, since the flange bore is larger than the pipe diameter, it usually requires more welding work than the other flanges. So the durability is not as long as the welding neck flange, all of these factors should be considered before choose a right flange.
A slip-on flange's bore size (internal diameter) is larger than that of the connecting pipe, which allows it to slide/slip onto the pipe (slip-onto the pipe). There is no full penetration weld between the pipe and the flange, thus there are limitations for its usage due to lower weld integrity.
The datasheets we have on this site are shown below. For simplicity sake, only datasheets that adhere to B16.5 are shown. ASME B16.5 covers flange dimensions from ½" to 24". For sizes larger than this, please visit our flange datasheets page.
| Class | Flat Face | Raised Face | Ring Type Joint |
|---|---|---|---|
| ANSI 150 | SO Flange ANSI 150 FF (in) | SO Flange ANSI 150 RF (in) | SO Flange ANSI 150 RTJ (in) |
| ANSI 300 | SO Flange ANSI 300 FF (in) | SO Flange ANSI 300 RF (in) | SO Flange ANSI 300 RTJ (in) |
| ANSI 400 | SO Flange ANSI 400 FF (in) | SO Flange ANSI 400 RF (in) | SO Flange ANSI 400 RTJ (in) |
| ANSI 600 | SO Flange ANSI 600 FF (in) | SO Flange ANSI 600 RF (in) | SO Flange ANSI 600 RTJ (in) |
| ANSI 900 | SO Flange ANSI 900 FF (in) | SO Flange ANSI 900 RF (in) | SO Flange ANSI 900 RTJ (in) |
| ANSI 1500 | SO Flange ANSI 1500 FF (in) | SO Flange ANSI 1500 RF (in) | SO Flange ANSI 1500 RTJ (in) |
| ANSI 2500 | SO Flange ANSI 2500 FF (in) | SO Flange ANSI 2500 RF (in) | SO Flange ANSI 2500 RTJ (in) |
For many users, slip on flanges continue to be preferred to welding neck flanges because of the following reasons:
Take the measurements of:
Some important features are as follows:
Pressure ratings define the maximum operating pressure a flange can withstand at a given temperature. American standards use “Class” ratings, while European standards use “PN” (nominal pressure). Our slip-on flanges cover all common pressure grades.
| ANSI Class | Equivalent PN | Rated Pressure (Bar) | Typical Application |
|---|---|---|---|
| Class 150 | PN16 | 16 | Water, gas, fire protection, HVAC |
| Class 300 | PN40 | 40 | Medium-pressure process pipelines, cooling water |
| Class 600 | PN63 | 63 | High-pressure utility lines, chemical processing |
| Class 900~1500 | PN100~PN160 | 100~160 | Special high-pressure industrial applications |
Class 150 (PN16) is the most common rating for slip-on flanges, suitable for the majority of low-pressure industrial and commercial applications. Higher classes are available for more demanding service conditions.
Pipe flanges are manufactured in all the different materials like stainless steel, cast iron, aluminium, brass, bronze, plastic etc. but the most used material is forged carbon steel and have machined surfaces.
Flanges are welded to pipe and equipment nozzle. Accordingly, it is manufactured from the following materials;
The list of materials used in manufacturing is covered in ASME B16.5 & B16.47.
Commonly used Forged material grads are
| Material | Fittings | Flanges | Valves | Bolts & Nuts |
|---|---|---|---|---|
| Carbon Steel | A234 Gr WPA | A105 | A216 Gr WCB | A193 Gr B7 A194 Gr 2H |
| A234 Gr WPB | A105 | A216 Gr WCB | ||
| A234 Gr WPC | A105 | A216 Gr WCB | ||
| Carbon Steel Alloy High-Temp |
A234 Gr WP1 | A182 Gr F1 | A217 Gr WC1 | A193 Gr B7 A194 Gr 2H |
| A234 Gr WP11 | A182 Gr F11 | A217 Gr WC6 | ||
| A234 Gr WP12 | A182 Gr F12 | A217 Gr WC6 | ||
| A234 Gr WP22 | A182 Gr F22 | A217 Gr WC9 | ||
| A234 Gr WP5 | A182 Gr F5 | A217 Gr C5 | ||
| A234 Gr WP9 | A182 Gr F9 | A217 Gr C12 | ||
| Carbon Steel Alloy Low-Temp |
A420 Gr WPL6 | A350 Gr LF2 | A352 Gr LCB | A320 Gr L7 A194 Gr 7 |
| A420 Gr WPL3 | A350 Gr LF3 | A352 Gr LC3 | ||
| Austenitic Stainless Steel | A403 Gr WP304 | A182 Gr F304 | A182 Gr F304 | A193 Gr B8 A194 Gr 8 |
| A403 Gr WP316 | A182 Gr F316 | A182 Gr F316 | ||
| A403 Gr WP321 | A182 Gr F321 | A182 Gr F321 | ||
| A403 Gr WP347 | A182 Gr F347 | A182 Gr F347 |
ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by "Grade".
The usual materials of flanges include stainless steel, carbon steel, aluminum and plastic. The choice of the material largely depends on the purpose of the flange. For example, stainless steel is more durable and is necessary for heavy use. On the other hand, plastic is more feasible for use in the home because of its reasonable price and easy installation. The materials used for flanges are under the designation of the American Society of Mechanical Engineers.
The most common materials for pipe flanges (forged grades) are: ASTM A105 (carbon steel high temperature to match A53/A106/API 5L pipes), A350 Grades LF1/2/3 (carbon steel low temperature to match A333 pipes), A694 Grades F42 to F80 (high yield carbon steel to match API 5L pipe grades), ASTM A182 Grades F5 to F91 (alloy steel flanges to match A335 pipes), A182 Grade F304/316 (stainless steel flanges to match A312 SS pipes), A182 Gr. F44/F51/F53/F55 (duplex and super duplex to match A790/A928 pipes) and various nickel alloy grades (Inconel, Incoloy, Hastelloy, Monel).
The material qualities for these flanges are defined in the ASTM standards.
For example, a carbon steel pipe can be identified with Grade A or B, a stainless-steel pipe with Grade TP304 or Grade TP321, a carbon steel fitting with Grade WPB etc.
Steel flanges must be packed with seaworthy packing method then delivery to customers, usually the packing way include wooden box, wooden pallet, iron & steel cage, iron & steel pallet etc.
Flange markings are governed by ANSI ASME codes. Flange marking includes;
ASME B16.5 and B16.47 standards cover permissible tolerances for inspection.
Because of the normal wooden boxes or wooden pallets have to do fumigation treatment, we usually use plywood pallet or plywood case or box to pack steel flanges without fumigation treatment.
When you partner with Sunny Steel, you can stop worrying about meeting deadlines thanks to our responsive and timely service. You'll also say goodbye to unnecessary shopping around. Instead, you'll get white glove service from an expert who understands your needs and can get you the materials you need quickly.