A Complete Guide On Steel Flanges! Looking to Buy a Flange?

What is a Flange?

A steel flange (forged, cut from plate, or rolled) comes in a variety of shapes and sizes to suit different applications. A flange is usually in the shape of a round disc and is used to connect two pipes together or to connect a pipe to a pressure vessel, valve, pump, integral flanged assembly or other component. A flange comes with holes for bolts around the rim. Bolts are used to connect two flanges which are typically attached to pipe ends with a gasket in between.

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Why do we use a flange? &#; Generally two pipes can be welded to each other, but once welded, it is not easy to disassemble unless it is cut by a cutter. However when a flange is used along with gasket and nuts and bolts a leak proof seal can be achieved. It can be easily disassembled when the pipeline fails and it also offers easy access for cleaning, inspection or modification.

Flanges are available in multiple shapes, as welding neck (the pipe is welded to the collar of the flange), threaded (the pipe is screwed on the flange), socket weld (fillet welds connections), lap joint (for connections using stub ends), slip on, etc. A flange can also be a plate for covering or closing the end of a pipe. This is called a blind flange. Thus, flanges are considered to be internal components which are used to support mechanical parts.

The ASME B16.5 and ASME B16.47 specifications cover US standard pipe flanges, the EN -1 specification covers European steel flanges.

A flange can be produced and designed to the specific pressure ratings; 150lb, 300lb, 400lb, 600lb, 900lb, lb and lb.

What are the Various Types of Flanges?

The standard type of steel flanges mostly used are:

Welding Neck Flange: This type of flange has a neck that is welded to the end of pipes. It is used for high pressure applications to reduce the concentration of stress. Generally machined from a forging, these flanges are typically butt welded to a pipe. Weld-neck flanges have a higher life expectancy than slip-on flanges under duress.

Slip On Flange: Slip-On flanges or SO flanges are commonly lower in price than weld-neck flanges, and to this effect are a popular choice for many users. 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.

Socket Weld Flange: A socket weld flange has a female socket in which pipe is fitted. Fillet welding is done from outside on the pipe. The socket welding flange is similar to a slip-on flange except it has a bore and a counter bore dimension. The counter bore is slightly larger than the O.D. of the matching pipe, allowing the pipe to be inserted into the flange similar to a slip-on flange. The diameter of the smaller bore is the same as the I.D. of the matching pipe A restriction is built into the bottom of the bore which sets as a shoulder for the pipe to rest on. When using a socket weld flange, the inner diameter needs to be the same as the inner diameter of the pipe. The socket flange is only suitable for pipes with a nominal diameter of 150 or less.

Lap Joint Flange: Lap Joint Flanges (LJ Flanges) are used on piping fitted with lapped pipe or with lap joint stub ends the combined initial cost of the two items being approximately one-third higher than that of comparable welding neck flanges. Lap joint flange is having two components, a stub end, and a loose backing flange. Stub end is butt welded to the pipe and Backing flange freely move over the pipe. The backing flange can be of different material than stub material and normally of the carbon steel to save the cost. Lap flange is used where frequent dismantling is required, and space is constrained. The lap joint flange is practically identical to a slip-on flange except it has a radius at the intersection of the bore and flange face. The lap joint flange is practically identical to a slip-on flange except it has a radius at the intersection of the bore and flange face. This radius is necessary to have the flange accommodate a lap joint stub end. Normally, a lap joint flange and a lap joint stub end are mated together is an assembly system.

Threaded Flange: Threaded Flanges are also known as screwed flange, and it is having a thread inside the flange bore which fits on the pipe with matching male thread on the pipe. Threaded flanges are widely demanded as pipe flanges i.e called as threaded pipe flanges used in different industrial applications. This type of joint connection is speedy and simple but not suitable for high presser and temperature applications. Threaded Flanges are mostly used in utility services such as air and water. Threaded (Screwed) flange is similar to the Slip-On flange, but the bore is threaded. Its chief merit is that it can be assembled without welding, explaining its use in low pressure services at ordinary atmospheric temperatures, and in highly explosive areas where welding create a hazard. Threaded flanges are not suitable for use where the temperature of the pipe changes sharply or the temperature is higher than 25°C and lower than -40°C.

Blind Flange: A Blind flange is round plate which has all of the relevant boltholes but no center hole, and because of this feature this flange is used to close off the ends of a piping systems and pressure vessel openings. It also permits easy access to the interior of a line or vessel once it has been sealed and must be reopened. The blind flange is used to close ends of piping systems. It is a kind of round plate with no center hold but with all the proper bolt holes. This blind flange is available in various sizes and materials and is used to provide positive closer on the ends of pipes, valves or equipment nozzles. This flange helps in easy access to a line once it has been sealed. The blind flange is sometimes custom made or machined to accept a nominal sized pipe to which reduction is being made. Blind Flanges are commonly used in petrochemical, pipe engineering, public services & water works. Blind pipe flanges are often used for high pressure applications.

In addition to the most used standard flanges, there are still a number of special steel flanges such as:

Orifice Flange: Orifice flanges are used instead of the standard pipe flanges when orifice plate or flow nozzle is used. In other words, orifice flanges are used with orifice meters. The basic purpose for this is to measuring the flow rate of either gases or liquids in the respective pipeline.

Long Welding Neck Flange: Long weld neck flange(LWN flange) is also call integral flange, it means a welding neck flange has a very long neck. Commonly, the welding neck flange has a tapered neck and a bevel end which is going to butt welding with the matching pipe. But the long weld neck flange, has a straight short pipe as the neck of a long weld neck flange.

Weldoflange & Nipoflange: The Weldoflange and Nipoflange is a combination of a Welding Neck flange and a supposedly Weldolet or Nipolet. The 2 components are manufactured in one piece, and not welded. These flanges are primarily in Branch connections. Furthermore, they have an expanded range of special flanges, fittings and branch connections.

Expander & Reducing Flange: Expanding and reducing flanges are used to increase or decrease the bore size of a pipeline. Expander and reducer flanges are a good alternative to butt weld reducers when the required pipeline bore reduction or increase is small (one or two sizes). For larger size changes, the use of buttweld fittings is recommended.

Selection of the Type of Flange Connection with Pipes

Steel pipes can be connected to flanges by welding the pipe with the flange (welded connection, made with weld neck, socket weld, slip on and lap joint flanges) or by screwing the flange onto the pipe (threaded connection, made using threaded flanges).

Welded connections are used for pipelines and piping systems featuring high pressures and temperatures, and diameters above 2 inches. Threaded connections are used for small diameter piping systems that are not subject to mechanical forces as expansion, vibration, contraction, oscillation (conditions that would crack the threaded joints). Let&#;s take a close look at the welded connections types.

Weld Neck Connection (Weld Neck Flanges)

Weld-neck flanges have a tapered hub with a butt weld end that can be welded to a butt weld pipe. The quality of the welded joint should be examined by dye penetrant test (DP) or using radiography and/or ultrasounds (UT).

The welded connection between a weld neck flange and a pipe features a good fatigue and mechanical stress performance.

Socket Weld Connection (Socket Weld Flanges)

Socket weld flanges are most preferred for use in high pressure piping systems generally below 2 inches (DN 50).

The pipe is fillet-welded to the hub of the socket weld flange. The quality of weld is of utmost importance in this kind of a flange connection, and appropriate inspection should be done before moving the system into operation.

Slip-On Connection (Slip On Flanges)

Slip-on flanges are generally preferred to weld-neck flanges due to their lower cost and installation speed (and ease).

The disadvantage of slip on flanges over weld neck flanges is that their strength is about 1/3 lower.

Due to lower strength slip on flanges are typically used for low-pressure, non-critical services.

The pipe is welded to both the hub and the bore of the flange. Slip-on flanges are used, generally, for pipe sizes greater than NPS 2¹&#;&#; (DN 65).

Lap Joint Connection (Lap Joint Flanges and Stub Ends)

This type of connection is sometimes used for pipelines in high-cost materials (as stainless steel and nickel alloys) as it helps to reduce the overall cost of the required flanged connections.

A lap joint connection is made by the combination of a stub end (which is the part welded to the pipe) and a backing flange, or lapped flange.

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Manufacturing Process for Steel Flanges

A flange is produced either by forging, casting, cutting, or rolling. We produce flanges mainly by forging, cutting, and rolling process.

Forged Flange Manufacturing Process

The forging process is usually composed of the following processes, namely, the selection of quality steel billet, heating, forming and cooling.

Inspection of Raw Material &#; The key raw material for producing flanges is steel billets or hot rolled bars. All raw materials purchased are supplied with test reports as per EN 3.1, with full traceability. It is the first compulsory step in the production process for flanges to guarantee good quality. The raw materials are re-tested inhouse for assurance on chemical composition, mechanical capacity and metallographic analysis.

Cutting Raw Material &#; Correctly and strictly controlling cutting size and proportion can ensure adequate control on the cost.

Heating &#; It is a very important step for flange quality. It is the necessary to record the heating temperature in details to avoid overheating. Overheating will destroy the structure of the metal and mechanical properties pf the raw materials.

Forging &#; Forging process is divided into free forging and die forging. The forging time and strength of flange is different for different pressure class.

Heat Treatment &#; The purpose of heat treatment is to eliminate the stress inside of flange so that the density is more evenly. Carefully recording the temperature of heat treatment and cooling time are the keys.

Forging Blank Inspection &#; After the heat treatment process has been carried out, a sample of the lot is chosen to test the chemical composition and mechanical property again to ensure all items are qualified.

Machining of Forged Blanks &#; In the machining process, the inspection is carried out along with the processing, so that to guarantee each part of flange is qualified. Machining is undertaken on CNC and/or lathe machines.

Finishing Goods Inspection &#; Finished products will be checked 100% before delivery to ensure the goods are perfect as per ASME, EN or customer standards.

Documentation &#; The whole production process and quality checks at different levels is documented as per standard operation procedure under ISO compliance. It is the guarantee for good quality.

Test Certificate: Since we are a ISO and PED certified manufacturer, we can issue test certificate as per EN 3.1 for all the goods at the time of delivery and inspection.

Packing: All forgings and flanges are packed in wooden crates or box or pallets to ensure secure movement of goods.

Plate Cut Flanges Manufacturing Process

The process here is relatively simple, with the key raw material being hot rolled plates. This process is mainly used for producing slip on plate flanges and blind flanges for lower thickness. All plates procured are accompanied with tested certificates as per EN 3.1.

Circles are cut from plates.

Heat treatment is not involved in this process of manufacturing flanges.

Drilling and machining is done on circles to achieve the desired dimensions.

Goods are visually inspected and marked with relevant standards.

Stainless Steel Flange: A Comprehensive Guide

Stainless steel flanges are crucial components in many industrial applications, ranging from pipelines, petrochemicals, and shipbuilding to food and pharmaceutical industries. They are known for their strength, durability, and resistance to corrosion, making them a popular choice for many engineers and project managers. In this article, we will delve into the world of stainless steel flanges, including their types, applications, and benefits.

Table of Contents

What is a Stainless Steel Flange?

Types of Stainless Steel Flanges

Weld Neck Flanges

Slip-On Flanges

Socket Weld Flanges

Lap Joint Flanges

Blind Flanges

Materials Used in Stainless Steel Flanges

Advantages of Stainless Steel Flanges

Applications of Stainless Steel Flanges

Factors to Consider when Selecting Stainless Steel Flanges

How to Install Stainless Steel Flanges?

Maintenance of Stainless Steel Flanges

Differences between Stainless Steel Flanges and Carbon Steel Flanges

Conclusion

FAQs

1. What is a Stainless Steel Flange?

A flange is a component that connects two pipes or equipment together. A stainless steel flange is made of high-quality stainless steel and serves as a seal for pipes or equipment. They provide easy access for inspection, cleaning, and repairs, making them a popular choice for many industries.

2. Types of Stainless Steel Flanges

There are several types of stainless steel flanges, each with its unique features and applications. Below are the most common types:

Weld Neck Flanges

Weld neck flanges have a long tapered hub, which provides an excellent flow of fluid and reduces erosion. They are welded to pipes, making them highly durable and resistant to bending and distortion.

Slip-On Flanges

Slip-on flanges slide over the pipe and are then welded in place. They are easy to install and ideal for low-pressure applications. They are also less expensive than other types of flanges.

Socket Weld Flanges

Socket weld flanges are similar to slip-on flanges, but they have a socket-shaped hub instead of a flat one. They are ideal for small-diameter pipes and high-pressure applications.

Lap Joint Flanges

Lap joint flanges consist of two parts: a backing flange and a stub end. The backing flange is bolted to the equipment, while the stub end is welded to the pipe. They are used for applications that require frequent dismantling.

Blind Flanges

Blind flanges are used to seal the end of a pipe or equipment. They are bolted to the equipment and provide easy access for inspection and cleaning.

3. Materials Used in Stainless Steel Flanges

Stainless steel flanges are made of high-quality stainless steel, which is an alloy of iron, carbon, and other elements. The most common types of stainless steel used in flanges are 304, 316, and 321.

4. Advantages of Stainless Steel Flanges

Stainless steel flanges offer several advantages, including:

Link to MIDAS

Resistance to corrosion and oxidation

High strength and durability

Easy to clean and maintain

Suitable for a wide range of temperatures and pressures

Can withstand harsh environments and corrosive fluids

5. Applications of Stainless Steel Flanges

Stainless steel flanges are used in various applications, including:

Petrochemicals and chemical industries

Oil and gas pipelines

Food and pharmaceutical industries

Water treatment plants

Shipbuilding and offshore platforms

Power generation plants

HVAC systems

6. Factors to Consider when Selecting Stainless Steel Flanges

Selecting the right type of stainless steel flange for your application is crucial to ensure maximum performance and durability. Below are some factors to consider when selecting stainless steel flanges:

The type of fluid or gas that will flow through the pipe

The temperature and pressure of the fluid or gas

The size and thickness of the pipe

The environment in which the pipe will be installed

The level of corrosion resistance required

The cost and availability of the flange

7. How to Install Stainless Steel Flanges?

Proper installation of stainless steel flanges is crucial to ensure maximum performance and durability. Here are some steps to follow when installing stainless steel flanges:

Clean the surface of the flange and the pipe to remove any dirt, grease, or rust.

Align the flange with the pipe and ensure that the bolt holes line up.

Insert the bolts and tighten them gradually, alternating between bolts to ensure even pressure.

Apply a sealant or gasket between the flange faces to ensure a tight seal.

Check for leaks and tighten the bolts if necessary.

8. Maintenance of Stainless Steel Flanges

Regular maintenance of stainless steel flanges is essential to ensure their longevity and optimal performance. Here are some tips for maintaining stainless steel flanges:

Inspect the flanges regularly for signs of wear, corrosion, or damage.

Clean the flanges regularly to remove any dirt or debris that may have accumulated.

Lubricate the bolts and nuts regularly to prevent corrosion and ensure proper tightening.

Replace any damaged or worn flanges or gaskets immediately to prevent leaks.

9. Differences between Stainless Steel Flanges and Carbon Steel Flanges

Stainless steel flanges and carbon steel flanges are both used in industrial applications, but they have some key differences. The main difference is that stainless steel flanges are more resistant to corrosion, making them ideal for applications that require high levels of corrosion resistance. Carbon steel flanges, on the other hand, are less expensive and ideal for applications that do not require high levels of corrosion resistance.

10. Conclusion

Stainless steel flanges are essential components in many industrial applications, offering strength, durability, and resistance to corrosion. Selecting the right type of flange for your application and ensuring proper installation and maintenance can help ensure optimal performance and longevity.

11. FAQs

Are stainless steel flanges expensive?

Stainless steel flanges can be more expensive than other types of flanges, but they offer several advantages, including resistance to corrosion and durability.

What is the most common type of stainless steel used in flanges?

The most common types of stainless steel used in flanges are 304, 316, and 321.

What is the difference between a slip-on flange and a socket weld flange?

A slip-on flange slides over the pipe and is then welded in place, while a socket weld flange has a socket-shaped hub and is ideal for small-diameter pipes and high-pressure applications.

Can stainless steel flanges be used in corrosive environments?

Yes, stainless steel flanges are resistant to corrosion and can withstand harsh environments and corrosive fluids.

How often should stainless steel flanges be inspected?

Stainless steel flanges should be inspected regularly for signs of wear, corrosion, or damage. The frequency of inspections will depend on the application and the level of use.

Understanding The Factors That Affect Flange Prices

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Flanges might seem like simple things, but they play a big role in connecting pipes and ensuring things run smoothly in industries like oil, gas, and construction.

Keep reading if you&#;re curious about why flange fittings can cost different amounts. We&#;ll break down the key things that make flange prices go up or down.

1. Quality matters:

One big reason flanges vary in price is the material. Think of it like buying shoes &#; leather shoes might cost more than canvas ones because they&#;re better quality and last longer.

Flanges are similar. Some items use stainless steel as material. This metal is strong and can handle tough situations. Others might use carbon steel, which is strong but less rust-resistant. The type of material affects how well the flange works and how long it lasts.

2. Size and style count:

Imagine buying a small T&#;shirt that costs less than an extra-large. Flanges work the same way. Their size and design affect the price. There are different types of flanges, like slip-on or weld neck.

Every object has a particular task, which people build with slight variations. Bigger and more complex flanges need more materials and work, so they cost more.

3. Handling pressure and heat:

Some flanges can handle pressure and high temperatures, while others can&#;t. Think of it like cooking &#; a pot made for high heat costs more than one for regular cooking.

Flanges that can handle extreme conditions need special materials and careful manufacturing, which can increase the price.

4. Industries uses:

Different industries use flanges for different jobs. For example, the energy sector needs flanges that can deal with oil and gas, which can be harsh. The medical industry might need flanges that are super clean and safe for medical gases.

These special needs can affect the price. Also, some industries have rules about the quality and safety of their flanges. Meeting these standards can add to the cost.

5. Supply and demand:

Think about toys everyone wants during the holidays &#; they can cost more because everyone buys them. Flanges work similarly. The price can go up if there&#;s a big demand for them.

Also, if the materials needed to make flanges are hard to find, that can drive the price higher, too.

6. Manufacturer matters:

Just like some brands of clothes are more famous (and sometimes more expensive) than others, the same can happen with flanges. Some manufacturers are known for making high-quality flanges that last a long time. Because of their reputation, they might charge more for their products.

7. Being kind to the planet:

Nowadays, many people care about the environment. This can affect flange prices, too. Some flange makers use eco-friendly materials and processes, but these choices can sometimes be more expensive.

However, they might save you money in the long run because they can be more efficient and last longer.

Conclusion

Flange prices aren&#;t random &#; they depend on a bunch of things. The flange size, material, design, pressure, temperature abilities, industry needs, supply and demand, brand reputation, and environmental choices all play a part.

When you&#;re looking for flanges, think about what you need. Do you need a super strong flange for extreme conditions or a regular one for simpler jobs? So, whether you&#;re building a pipeline or working on a construction project, understanding these factors can help you make the right choice for your needs and budget.