4 Advice to Choose a Slip on Flange

posted September 27, 11:07 AM
--------------------------------------------------------------------------------
Hello,

Also......

Welding Neck Flanges (Weldneck Flanges) - are distinguished from other by their long tapered hub and gentle transition of thickness in the region of the butt weld joining them to the pipe. The long tapered hub provides an important reinforcement of the flange from the standpoint of strength and resistance to dishing. The smooth transition from flange thickness to pipe wall thickness is extremely beneficial under conditions of repeated bending, caused by line expansion/contraction or other forces, and produces a strength equivalent to that of a butt welded joint between pipes. This type of flange is preferred for every severe service condition, whether this results from high pressure, from sub-zero or high temperatures or from extreme loading conditions. This type of flange is recommended for handling explosive, flammable or costly liquids, where loss of tightness or local failure must be minimized.

Slip-On Flanges - continue to be the preferred flanges by most installing contractors because of their lower first cost, the reduced accuracy required in cutting the pipe to length, and the greater ease of alignment of the piping assembly. Unfortunately, their final installed cost is likely not much less (if any) than that of welding neck flanges. Their calculated strength under internal pressure is approximately 2/3 that of the weldneck flange and their life under fatigue is about 1/3 that of weldneck flanges. For these reasons, slip-on flanges are limited to line sizes 1/2" to 2 ½" in the Class ANSI standard.

Lap Joint Flanges - are primarily installed with lap joint stubs, the combined initial cost of which is approximately 1/3 higher than that of comparable weldneck flanges. Their pressure holding ability is little, if any, better than that of a slip-on flange and their fatigue life is only 1/10 that of welding neck flanges. The primary use of lap joint flanges is in carbon or low alloy steel piping systems in services necessitating frequent dismantling for inspection and cleaning and where the ability to swivel flanges and to align bolt holes simplifies the erection of large diameter or unusually stiff piping. Their use at points where severe bending stress occurs should be avoided.

Threaded Flanges - made of steel should be confined to special applications. Their chief merit lines in the fact that they can be assembled without welding. They are often used in extremely high pressure service applications, particularly at or near atmospheric temperature, where alloy steel is essential for strength and where the necessary post-weld heat treatment is impractical. Threaded flanges are unsuited for conditions involving temperature or bending stresses of any magnitude, particulary under cyclic conditions, where leakage through the threads may occur in relatively few cycles of expansion or contraction or stress. Seal welding is sometimes accomplished to overcome this weakness, but cannot be considered as entirely satisfactory.

Socket Weld Flanges - are available for use on small-size high pressure piping. Their initial cost is about 10% higher than that of slip-on flanges. When provided with an internal weld, their static strength is equal to that of double-welded slip-on flanges while their fatigue strength is 50% greater. Smooth bore conditions are possible by grinding the internal weld, unlike with slip-on flanges which require that the flange face be beveled and re-faced after welding. The internally welded socket type flange is becoming increasingly popular in the chemical process piping industry.

Regards, John.

The Pipeline and Hazardous Materials Safety Administration under the US Department of Transportation estimate that approximately 160,521 miles of liquid petroleum pipeline and around 1,585,672 miles of natural gas pipeline are across the nation. In , the gas-integrated transportation networks delivered over 28.3 trillion cubic feet of natural gas to consumers.

With competitive price and timely delivery, MIDAS sincerely hope to be your supplier and partner.

Flanges play a critical role in the gas and oil piping systems, connecting valves with other equipment. Pipe flanges are the second-most commonly used joining mechanism after welding. Flanges provide added flexibility that allows the disassembly and assembly of pipe systems. They provide easy access during the inspection, repairs, and cleaning of the gas and oil pipes.

But the point is, how to find suitable flanges for your company? Here are four factors to keep in mind during the flange selection process.

Flange types

Flanges come in many kinds for industrial use. You may need to choose an ideal flange design that fits your piping systems. The most common types of flanges used in the petrochemical industry are:

• Slip-on flange
• Welding neck flange
• Socket weld flange
• Blind flange
• Lap joint flange

Other special flanges commonly used in the gas and oil industry include:

• Nipoflange
• Reducing flange
• Expander flange
• Orifice flange
• Long weld neck flanges

The flange design and face types may significantly impact the final performance of the last system.

For more information, please visit Slip on Flange.

Material

Forged carbon steel pipe flanges are the top common type in the market. Additionally, you may find the flanges manufactured from bronze, cast iron, aluminum, and stainless steel. You may also find flanges with specialty metals like Monel, Inconel, and chrome-moly. The kind of materials depends on the piping systems and industrial application. It ensures that they are durable and robust enough in the long run. However, in most instances, the flange comes with the same material as the pipes.

Size

It would be best to look into the flange dimensions and size for the right fit. You may need to be keen on how the flange interfaces with the pipes and gaskets to ensure an ideal size. A few standard dimensions considerations include:

• Pipe size
• Thickness
• Bolt circle diameter
• Inner diameter
• Nominal bore size
• Outside diameter

These dimensional factors may come in handy when updating or maintaining piping systems.

Classifications

All the flanges fall under different categories specified by ASTM or ASME standards. A specific flange kind has characteristics that may significantly impact its performance across different industrial environments. Steel pipes are available in a lot of pressure and style classes. The metal flanges are classified from to 200# rating. A few standard classifications used in the petrochemical industries are:

• 150#
• 300#
• 600#
• 900#
• #
• #

The categories vary depending on the temperature and pressure tolerances, flange size, design, or material used. The pressure ratings usually decrease when the temperature tends to rise.

The company is the world’s best Thread Flange supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.