3D Pipe Bending

3D Pipe Bending

A 3D bend is a bend in which the radius of the curve is equal to 3 times the diameter of the pipe.

A tube can be bent in several angels and directions. However, some of the most common and simple bends include the formation of an elbow that ranges from two degrees 90 degrees.

What is a 3D pipe bend?

A 3D bend is a bend in which the radius of the curve is equal to 3 times the diameter of the pipe. It is a smoother bend than a 1.5D bend, which looks almost like a regular 90-degree right angle, but it is a sharper bend than a 5D bend, which looks like a smooth arc between two perpendicular pieces. 3D pipe bending refers to the process of bending pipes or tubes in three dimensions, allowing for complex and custom-shaped bends.

How do you calculate 3D pipe bend?

3D pipe bending is a pipe bend that the bend radius is 3 times the pipe outside diameter. The RADIUS of a 5D pipe bend is actually what is 5 times the nominal diameter. So if you had a 10″ diameter pipe, the radius of the centerline of the bend would be 50 inches. Larger numbers have smoother curves.

What size is a 3D bend?

3D Bend is bend radius 3 times of the pipe outside diameter, for example if a 3D pipe bend used in a 10 inch pipelines, the bending radius would be 30 inches. Same with elbow (1D or 1.5D), 3D bend also ranges different degrees like 45 degree, 60 Degree and 90 Degree.

3D pipe bending involves using specialized equipment and machines to form pipes into various shapes and curves along three planes. This technique is commonly used in industries such as aerospace, automotive, and construction to create complex piping systems for various applications. 3D pipe bends allow for more efficient and effective use of space while improving fluid flow and reducing the risk of leaks or breaks.

3D bends are pipe bends whose radius is three times the outside diameter of the pipe. Others are the U-bends that have a bend of 180 degrees. In any project using metal pipes, there are likely to be a few places where the pipe has to go around a corner, or has to be bent to follow a certain contour. In many cases, with proper planning and a good design, these bends can be made using pre-fabricated elbows, which come in popular angles like 45 or 90 degrees and several common bend radii, typically referred to as either short or long-radius bends.

Sometimes, however, a custom bend will be required to make the pipe fit precisely around an obstacle or to follow a curve perfectly. Pipe can be custom-bent with presses or more complex machines using one of several common methods, including ram bending, rotary draw bending, compression bending and three roll bending, among others. Separate dies are typically required for each size of pipe and each different bend radius, except on more complex machines.

So what are 3D bends and what are they for?

A 3D bend is a bend in which the radius of the curve is equal to 3 times the diameter of the pipe. It is a smoother bend than a 1.5D bend, which looks almost like a regular 90-degree right angle, but it is a sharper bend than a 5D bend, which looks like a smooth arc between two perpendicular pieces.

Here are a few of the places where you will commonly find 3D bends being used:

1. Automotive Exhaust Systems

Both manufacturer-supplied and custom exhaust systems for cars and trucks often feature a wide assortment of bends to maneuver around various obstacles on the underside of the car, such as the engine, transmission, cross-members and the fame. Most vehicle exhausts feature custom compound beds, and the fabricators generally prefer smoother curves, like 3D bends or even 5D bends, because they reduce the turbulence and back-pressure inside the exhaust system, and that can help increase an engine’s performance.

2. Automotive Roll Cages

Off-roading can be a very competitive sport, or, more simply, an expensive hobby. One of the many dangers when rock-crawling, mudding or generally pushing a vehicle beyond its limits, is the possibility of rolling the vehicle over. To prevent injury and damage to the vehicle, a quality roll cage is an absolute necessity. Many roll cages are custom formed from metal pipe, often chromoly steel, using an assortment of bends, including the common 3D bend. Each piece is bent, cut and welded together to make a complete roll cage that is both durable and aesthetically pleasing.

3. Structural Frames

3D bends are very common in structural frames of all kinds. These can range from the frames of custom automobiles, to the frames of buildings, or even airplanes or spacecraft. Often, to build a structural frame, pipe is bent, cut and welded together to make a strong skeleton, and then sheet metal is attached via screws or welds to create a completed assembly, which is both extremely strong and resistant to the elements. When built using aluminum, titanium or certain alloys, it can also be lightweight and corrosion-resistant.

4. Furniture

Many types of furniture incorporate tubular steel and 3D bends for either structural or aesthetic purposes. Tables frequently use tubular steel legs, with bends where they meet the tabletop to provide support. Metal chairs, couches and futons with tubular frames often use similar bends to provide a nice gentle curve that is both pleasing to the eye and structurally rigid. Shelving units can also incorporate custom bends, either for decoration or for structural integrity.

5. Fencing

The 3D bend is also quite common in fencing, for both decorative and structural uses. It is seen extensively in galvanized chain-link fencing, especially to add a gentle curve to gates and other decorative items, or in custom-designed fencing. Pipe is also used regularly in fencing for cattle, horses and other livestock, as well as for domestic pets, and often decorative touches are added that require custom bends.

6. Plumbing

In the plumbing industry, 3D bends are quite common. They are incorporated anywhere that standard elbows cannot be relied upon to bypass obstacles or to change the angle of the pipe. In pipes that contain high-viscosity liquids or fluids that require reduced turbulence, the smoother 3D bend is often preferable to sharper bends. Custom bends are used in plumbing of all kinds, from the pipes in your home, to the pipes in chemical plants, food processors or refineries.

7. Wiring Conduit

Wiring conduit is designed to protect electrical cables from the weather, accidental damage and other dangers. When wiring conduit is required on an electrical job, often it must be bent to go around corners or other obstacles. Typically, smoother curves like 3D or 5D bends are used instead of sharp curves, because it makes it much easier to fish the wire through the conduit after it is installed. Electricians usually carry their own tools to bend small-diameter conduit, though for larger-diameter versions, they may require custom bending services.

8. Pipelines

Gas and oil pipelines, like any plumbing system, often use 3D bends in many places along their lengths. Unlike typical household pipes, however, these are typically much larger, and require some serious machinery to do custom bends. Gentle bends help the high-viscosity oil flow through the pipes easier, and they help natural gas flow smoother, reducing pipe fatigue and the chance of leaks.

9. Hand Rails

An often-overlooked area where 3D bends are used is in the hand rails for stairways or walkways, as well as the safety rails used to provide handicap access. Custom bends are often used to follow curves, go around corners or to provide mounting points at each end of the pipe. Sometimes the bends are also used strictly for decorative purposes.

10. Art Projects

In many art projects, tubular steel is used to create a frame, upon which the artist builds the rest of the piece. Custom bends are often used to create gentle-flowing lines and other aesthetic features, which many times are covered up by other materials. The frame creates a strong base for the rest of the piece, and determines its overall shape.

If you have a project that calls for 3D bends, it often may not be feasible to buy the equipment to produce them yourself. The tools can be prohibitively expensive, and they require a significant amount of training and practice to operate them properly. Fortunately, there are services available that will custom-bend pipe to your exact specifications, saving you the expense and the hassle of buying your own equipment.

Methods of bends in carbon steel

While the industry provides various means for bending the carbon steel pipe to the 5D bend, heat induction is the most widely-known–but not the most popular–technique in the industry. The pipe to be bent is subjected to extreme temperature, and when at the desired heat, a mode or model in the dimensions of the 5D bends is forced through the heated pipe, causing the pipe to conform to the bend of the 5D pipe dimensions. Carbon steel is the hardest pipe material used in this manner, and heat induction is the best means to curve the carbon steel pipe into the 5D curvature.

Uses

Heat-processed 5D bend pipes are used in all oil and gas lines, and the factory testing exceeds the quality standards required by the oil and gas industry. This is an industry where quality standards can be linked to safety standards.

What You Are Buying

Customers obtain a wide range of bend geometries and total design flexibility with customized radius and angle. Qualified subcontractors carry out hot induction bending with state-of-the-art technology, giving full control of the bending process, as well as total monitoring of all bending parameters.

1) Heat Induction Bends for Oil and Gas Industry
The production of high-quality bends depends on the manufacturing process of the steel pipe that is transformed into the bend. During the hot-induction bending process, unavoidable thinning occurs. Therefore, a custom- and precision-made mother pipe must be produced in order to comply with minimum wall thickness after the bending is complete.

Heat treatment is carried out on each bend in order to achieve the required degree and mechanical properties after bending. For critical applications (such as high-strength steel, heavy wall, sour service or low-temperature) full quenching and tempering after bending is still performed as a preferred process. Machining the bend ends guarantees top tolerances of inside diameters of the pipe. We therefore ensure the bend has the minimum working strengths of the mother pipe.

World-class bending manufacturers provide high quality bending solutions for oil and gas pipelines, either onshore or offshore. The bends manufacturing and testing procedures exceed all quality standards required by the oil and gas industry.

2) Cold Bending Process

High quality bending solutions are more than critical. Cold-bending is commonly used over hot-bending because certain types of steel and metal alloys can be weakened. You cannot allow the pipes to be weakened in any way as this can lead to damage of your product, your plant, or cause risks of injury to your employees. Cold-bending is also preferred by many industries because of its affordability, with costs being less than that of heat induction.

Cold-bending 5D bends is a continuous operation where a long strip of metal, usually steel, is passed through sets of rollers, with each set of rollers performing only a part of the bend, until the desired cross-section profile is obtained. Roll-forming is ideal for producing parts with long lengths or in large quantities. Roll-Forming is also generally a lower cost process than other metal forming processes. Cold-processed bends are used in construction, water piping and as machinery parts.

Sunny Steel provides fast, dependable metal custom-bending for:

We specialize in bending, fabricating and testing of heating and cooling coils. We are proud of our leading reputation in the industry with our attitude of professional workmanship and on-time delivery. Some of our advantages over competitors include:

Sunny Steel fabricates all types and sizes of cooling coils from 1/8″ pipe to 8″ pipe and all alloys.

What is the difference between a 3R and a 3D elbow?

There is no difference between 3R and 3D.

What does 3D or 6D mean for pipe fittings ?

Larger numbers have smoother curves.


How are 3D bends formed?

However, some of the most common and simple bends include the formation of an elbow that ranges from two degrees 90 degrees. Others are the U-bends that have a bend of 180 degrees.

Creating 3D Bends

The process involves the use of machines and mechanical force. Normally, pipe or tube bending machines are human powered, hydraulic assisted, or even pneumatic powered. The following are some of the most commonly used pipe bending processes.

Three-Roll Push Bending

This is one of the most commonly used processes. It is used to come up with bending geometrics that include multiple plane bending curves. Normally, the profile is led through a bending roll and the supporting roll or even rolls, while at the same time being pushed through the tool. The bending radius is normally determined by the position of the forming radius. This is one of the most flexible processes used in the creation of bends, for multiple radii can be actually obtained.

Rotary Draw Bending

This is one of the most precise technologies used to create 3D bends. It uses a feature called ‘die sets’ that has a constant center line radius. Rotary draw benders can be programmed to store several bend works with different degrees when it comes to bending. Technically, an IDX (positioning index table) is at all times attached to the rotary bender. This enables the operator to create complex bends that have varying planes. Rotary benders are largely used in tube bending.

Heat Induction

When it comes to this bend tubing process, an induction coil is normally placed at the bend point of the pipe. Thereafter, the area is subjected to temperatures ranging from 800 to 2200 degrees Celsius. When it is hot, pressure is actually applied to bend the pipe. Finally, the pipe can be passed through cold air or water. Normally, this process is used in extremely large pipes such as gas pipes lines

Hot-Slab/Sand Packing Forming

In this process, the pipe is filled with sand and the ends caped. The pipe is then passed through a furnace with temperature of 870 degrees Celsius. Thereafter, the pipe is placed on the slab and the pins set in it. You can then bent the pipe around the pins using a tool such as the winch, or you can even apply some mechanical force. The sand that is normally put in the pipe minimizes any distortion in the cross section of the pipe.

Press Bending

This will probably be one of the first processes used on cold tubing and even pipes. Normally, a die is pressed against the pipe. This will force the pipe to fit the shapes. However, this process comes with its own drawbacks since the internal area is not supported. It results in some kind of deformation and perfect 3D bends and 5D bends will not be achieved.

Why use 3D & 5d pipe bends?

3D pipe Bend

Diagram of ASME B16.49 induction bend, 90° 3D Bend with Tangent lengths.

Larger radius bends offer several advantages for fluid flow in pipes. They provide smoother flow for various mediums such as water, slurry, oils, solids, and more. This reduced resistance results in improved flow efficiency compared to 1D or 1.5D bends. Additionally, longer bend radii help minimize turbulence, especially when compared to standard fittings.

When planning your piping project, it's essential to assess whether traditional 1D or 1.5D bends can effectively meet your requirements. If there are any doubts, it's advisable to consider using 3D or 5D bends to optimize your system's performance.

10 applications where 3D bends are used

In any project using metal pipes, there are likely to be a few places where the pipe has to go around a corner, or has to be bent to follow a certain contour. In many cases, with proper planning and a good design, these bends can be made using pre-fabricated elbows, which come in popular angles like 45 or 90 degrees and several common bend radii, typically referred to as either short or long-radius bends.

Sometimes, however, a custom bend will be required to make the pipe fit precisely around an obstacle or to follow a curve perfectly. Pipe can be custom-bent with presses or more complex machines using one of several common methods, including ram bending, rotary draw bending, compression bending and three roll bending, among others. Separate dies are typically required for each size of pipe and each different bend radius, except on more complex machines.

So what are 3D bends and what are they for?

A 3D bend is a bend in which the radius of the curve is equal to 3 times the diameter of the pipe. It is a smoother bend than a 1.5D bend, which looks almost like a regular 90-degree right angle, but it is a sharper bend than a 5D bend, which looks like a smooth arc between two perpendicular pieces.

Here are a few of the places where you will commonly find 3D bends being used:

Automotive Exhaust Systems

Both manufacturer-supplied and custom exhaust systems for cars and trucks often feature a wide assortment of bends to maneuver around various obstacles on the underside of the car, such as the engine, transmission, cross-members and the fame. Most vehicle exhausts feature custom compound beds, and the fabricators generally prefer smoother curves, like 3D bends or even 5D bends, because they reduce the turbulence and back-pressure inside the exhaust system, and that can help increase an engine’s performance.

Automotive Roll Cages

Off-roading can be a very competitive sport, or, more simply, an expensive hobby. One of the many dangers when rock-crawling, mudding or generally pushing a vehicle beyond its limits, is the possibility of rolling the vehicle over. To prevent injury and damage to the vehicle, a quality roll cage is an absolute necessity. Many roll cages are custom formed from metal pipe, often chromoly steel, using an assortment of bends, including the common 3D bend. Each piece is bent, cut and welded together to make a complete roll cage that is both durable and aesthetically pleasing.

Structural Frames

3D bends are very common in structural frames of all kinds. These can range from the frames of custom automobiles, to the frames of buildings, or even airplanes or spacecraft. Often, to build a structural frame, pipe is bent, cut and welded together to make a strong skeleton, and then sheet metal is attached via screws or welds to create a completed assembly, which is both extremely strong and resistant to the elements. When built using aluminum, titanium or certain alloys, it can also be lightweight and corrosion-resistant.

Furniture

Many types of furniture incorporate tubular steel and 3D bends for either structural or aesthetic purposes. Tables frequently use tubular steel legs, with bends where they meet the tabletop to provide support. Metal chairs, couches and futons with tubular frames often use similar bends to provide a nice gentle curve that is both pleasing to the eye and structurally rigid. Shelving units can also incorporate custom bends, either for decoration or for structural integrity.

Fencing

The 3D bend is also quite common in fencing, for both decorative and structural uses. It is seen extensively in galvanized chain-link fencing, especially to add a gentle curve to gates and other decorative items, or in custom-designed fencing. Pipe is also used regularly in fencing for cattle, horses and other livestock, as well as for domestic pets, and often decorative touches are added that require custom bends.

Plumbing

In the plumbing industry, 3D bends are quite common. They are incorporated anywhere that standard elbows cannot be relied upon to bypass obstacles or to change the angle of the pipe. In pipes that contain high-viscosity liquids or fluids that require reduced turbulence, the smoother 3D bend is often preferable to sharper bends. Custom bends are used in plumbing of all kinds, from the pipes in your home, to the pipes in chemical plants, food processors or refineries.

Wiring Conduit

Wiring conduit is designed to protect electrical cables from the weather, accidental damage and other dangers. When wiring conduit is required on an electrical job, often it must be bent to go around corners or other obstacles. Typically, smoother curves like 3D or 5D bends are used instead of sharp curves, because it makes it much easier to fish the wire through the conduit after it is installed. Electricians usually carry their own tools to bend small-diameter conduit, though for larger-diameter versions, they may require custom bending services.

Pipelines

Gas and oil pipelines, like any plumbing system, often use 3D bends in many places along their lengths. Unlike typical household pipes, however, these are typically much larger, and require some serious machinery to do custom bends. Gentle bends help the high-viscosity oil flow through the pipes easier, and they help natural gas flow smoother, reducing pipe fatigue and the chance of leaks.

Hand Rails

An often-overlooked area where 3D bends are used is in the hand rails for stairways or walkways, as well as the safety rails used to provide handicap access. Custom bends are often used to follow curves, go around corners or to provide mounting points at each end of the pipe. Sometimes the bends are also used strictly for decorative purposes.

Art Projects

In many art projects, tubular steel is used to create a frame, upon which the artist builds the rest of the piece. Custom bends are often used to create gentle-flowing lines and other aesthetic features, which many times are covered up by other materials. The frame creates a strong base for the rest of the piece, and determines its overall shape.

If you have a project that calls for 3D bends, it often may not be feasible to buy the equipment to produce them yourself. The tools can be prohibitively expensive, and they require a significant amount of training and practice to operate them properly. Fortunately, there are services available that will custom-bend pipe to your exact specifications, saving you the expense and the hassle of buying your own equipment.

What’s a pipe bend?

Bend on process

Bend on process

A pipe bend is the generic term for what is called in piping as an “offset” – a change in direction of the piping. A bend is usually meant to mean nothing more than that there is a “bend”– a change in direction of the piping (usually for some specific reason) – but it lacks specific, engineering definition as to direction and degree. Bends are usually custom-made (using a bending machine) on site and suited for a specific need.

Pipe bends typically have a minimum bending radius of 1.5 times pipe radius (R). If this bending radius is less than 1.5R, it is called Elbow. Reference to any international / industry standard need to be traced. 1.5, 3 and 4.5 R are the most common bending radii in industry.

A pipe bend typically flows smoother since there are not irregular surfaces on the inside of the pipe, nor does the fluid have to change direction abruptly.

The most basic difference of them is the elbow relatively short than bend, R = 1D to 2 D is elbow More than 2D is bend. In the production process, cold bends can use Bending Machine to bend by ready-made straight bend. One-time completed also don’t need second corrosion. But elbow need manufacturers make to order, to do anti-corrosion, order cycle is long. Elbow price is higher than bend. But cost performance is much higher than bend. It is well-known that bend do not have anticorrosive processing is easy damaged, but the price is cheap so are  used very much in some demand which not very high engineering.

Pipe bends are used in many industries, including chemical, oil and gas, electric, metallurgy and shipbuilding. Pipe bends function as structural passageways to facilitate the transfer of substances, such as water and fuel. Some have a short radius while others have a long radius. Long radius bends give less frictional resistance and allow for less pressure drop when compared to short radius bends. When selecting the type of pipe bend, it’s important to choose one that is compatible to the application.

The Radii of Bend Pipes

Bend pipes come in all types of radii, including 3D bends, 4D bends, 5D bends, 8D bends and 10D bends. The radius in 5D bends is five times the nominal diameter. With a 10-inch diameter pipe, the radius of the centerline of the bend would be 50 inches. Pipe bending for the specified radii is both art and science. And with today’s modern machines and advanced software, pipe bending is highly precise. With the right machine, lubrication, tooling and material, achieving the perfect bend is a sure thing.

The Differences Between Bends and Elbows

Although the words bends and elbows are often used as synonyms, there are some differences. Bend is a term for any offset of direction in the piping while elbow is an engineering term. Elbows have limitations to angle, bend radius and size. Most angles are either 45 degrees or 90 degrees. All other offsets are specifically pipe bends. And while elbows have sharp corners, bends never do. The most basic different between a bend and an elbow is the radius of curvature. Bends have a radius more than twice the diameter, and elbows have a radius of curvature between one and two times the size of the pipe’s diameter. All elbows are bends, but not all bends are elbows.

Induction Bending for Creating 5D Bends

Induction bending is one of the means of bending pipes for 5D and other bends. Local heating, using high-frequency induced electrical power, is applied. An induction coil is placed around the pipe and heats a circumferential area of the pipe at a temperature between 850 to 1100 degrees Celsius. When the right temperature is reached, the pipe moves through an induction coil while an arm applies the bending force. There are many benefits to induction bending. It allows for large radii for smooth flow of fluid, reduces the number of welds in a system and fabricates bends quickly. With faster production, efficiency is ramped up. It’s also a clean process, as no lubrication is needed, and water is recycled.

Ram-Type Bending

Ram-type bending is an old and effective bending method for bending pipes, including 4D bends and 5D bends. This method is often used in muffler shops. It’s also one of the least expensive ways to bend pipe. A hydraulically driven ram forces the pipe against pivot blocks or rollers. Often, a ram tool is used to produce a concave surface and to prevent stretching on the exterior of the bend. The only downside is that ram-type bending is not as controllable as other methods.

Roll Bending

Roll bending is commonly used for pipes in the construction industry. Rolls are positioned vertically or horizontally to produce very large radii. The pinch-style roll bender is one of the machine types used for roll bending. A tube feeds between the lower and upper roll to produce the wanted bend angle. Some applications may require an additional roll to guide the tube outward when the coil is being formed.

Mandrel Bending

The mandrel bending pipe method is effective when the least amount of deformation is desired. The pipe is supported with a mandrel support to bend the pipe. The pipe is drawn through a counter bending die for further bending. This method of pipe bending is used in the manufacture of heat exchanger tubing, dairy tubing and exhausts like turbocharger and custom made ones. This method produces a non-deformed diameter every time.

Rotary Draw Bending

Rotary draw bending is often used for bending pipe when a constant diameter and good finish are desired. The pipe is drawn through a stationary counter-bending die onto a fixed radius former die. It’s used for roll cages, stock car chassis and other types of pipes.

Centerline Radius, Outside Diameter and Wall Thickness

Centerline radius, outside diameter and wall thickness are important variables with bending pipe methods. Plus, every pipe schedule has a nominal wall thickness. And since wall thickness can vary, any variations need to be accounted for. Other bending variables include the neutral line, outside bend radius and inside bend radius. Pipes experience spring back after bending. The harder the pipe and small the bend’s centerline radius, the more spring back, which results in radial growth. Copper pipes have less radial growth than steel pipe due to its less spring back. In pipe bending, consistency, size and quality of the weld seam matter for centerline radius, outside diameter and wall thickness. When these are right, the perfect bend can be created.

Material Used for 5D Bends, 6D Bends and Others

Common materials used for pipes and pipe bends include carbon, stainless steel, titanium, aluminum and cast iron. There are also plastic pipes of various grades. It’s important to select the right material for the right application, including the pipe fittings. Pipe fitting materials include aluminum, brass, bronze, cast iron, vitrified clay and many others. Pipe fittings must satisfy many criteria. The materials must be compatible with the fluids being transported, different pressure levels and fluctuating temperatures. Materials should also conform to certain standards like DIN, ASME, NPT and BSP. Surface finish is also important, and pipe fittings should have a corrosion-resistant property.

In some fields, the schedule 40 and schedule 80 are used for pipes. However, there are many other schedules due to increased pressure demands. The schedule of a pipe refers to its pressure rating. The higher the schedule, the higher pressure it can have. As the schedule increases, the wall thickness increases. When choosing pipe bends, it is critical to consider the schedule of the pipe. Schedule 80 is often used for heavy-duty while schedule 40 is often used for light-duty. Be sure to choose the appropriate schedule for the pipe bend, and it will be a perfect match.

Bend geometry Figure. Flow in a standard, long-radius bend is illustrated here, with typical flow patterns, wear points and reacceleration zone shown

Bend geometry

Pipe bends can take a variety of different geometries, which can have a significant influence on particle impact angle. Basic long-radius bends are the most commonly used because they provide the most gradual change in direction for solids, and because the angle of impact on the pipe wall is relatively small, which helps to minimize the risk of attrition or erosion.

Common-radius bends are made by bending standard tubes or pipes (Figure). The radius of curvature, RB, may range from 1 to 24 times the tube diameter, D. Common-radius bends can be loosely classified as follows: Elbow (RB /D = 1 to 2.5); Short radius RB /D = 3 to 7; Long-radius (RB /D = 8 to 14; Long sweep (RB /D = 15 to 24).

Pressure drop associated with bends

As particle impacts occur, particularly against bends, there will be a significant reduction in particle velocity. These particles will then have to be re-accelerated back to their terminal velocity, which will add significantly to the pressure drop — and hence, energy loss — for the conveying system. This is particularly true after short-radius bends.

The pressure drop in a bend depends on the ratio of bend radius to pipe diameter, the gas velocity, Ug, and the internal roughness, k, of the pipe. When a two-phase, gas-solid suspension undergoes a directional change in a pipeline, the bend naturally acts as a segregator of the two phases. Centrifugal forces act on the particles, concentrating them near the outer wall of the bend. Friction coefficients within the bend will be different than those in the adjacent straight sections.

Size

The bend is used to change the direction of run of pipe.it advantage is can matach long distance transition requirements,so it is commonly that bends dimension according to customer design.

Constants for Pipe Bends:

Formula:L = R x BL = Length of pipe requiredR = Radius of bendB = Constant from table used to find “L”L =30 x 1.5705 =47.115 in.or 47-1/8”

Standards accord to:

  • ASME B16.9
  • ASME B16.28
  • ANSI/ASME B16.25
  • MSS SP-97

Pressure: SCH5 to SCH160

Bending radius(R): R=3D, 5D, 7D and 12D
Bending angle (θ):15°, 30°, 45°, 60°, 90°, 135°, 180°

Outer diamete(D): D≤1800mm
Wall thickness(T): T≤120mm
Straight Length (L): The length between two ends general from 300mm-1500mm

Example: Find the length of pipe required to make a 90 bend with a radius of 30"

Pipe bend design
Nominal pipe Outside Diameter at Bevel Center to End
DN size D1 D2 C M
Series A Series B Series A Series B
20×15 26.9 25 21.3 18 29 29
25×20 33.7 32 26.9 25 38 38
25×15 33.7 32 21.3 18 38 38
32×25 42.4 38 33.7 32 48 48
32×20 42.4 38 26.9 25 48 48
32×15 42.4 38 21.3 18 48 48
40×32 48.3 45 42.4 38 57 57
40×25 48.3 45 33.7 32 57 57
40×20 48.3 45 26.7 25 57 57
40×15 48.3 45 21.3 18 57 57
50×40 60.3 57 48.3 45 64 60
50×32 60.3 57 42.4 38 64 57
50×25 60.3 57 33.7 32 64 51
50×20 60.3 57 26.9 25 64 44
65×50 76.1(73) 76 60.3 57 76 70
65×40 76.1(73) 76 48.3 45 76 67
65×32 76.1(73) 76 42.4 38 76 64
65×25 76.1(73) 76 33.7 32 76 57
80×65 88.9 89 76.1(73) 76 86 83
80×50 88.9 89 60.3 57 86 76
80×40 88.9 89 48.3 45 86 73
80×32 88.9 89 42.4 38 86 70
90×80 101.6 - 88.9 - 95 92
90×65 101.6 - 76.1(73) - 95 89
90×50 101.6 - 60.3 - 95 83
90×40 101.6 - 48.3 - 95 79
100×90 114.3 - 101.6 - 105 102
100×80 114.3 108 88.9 89 105 98
100×65 114.3 108 76.1(73) 76 105 95
100×50 114.3 108 60.3 57 105 89
100×40 114.3 108 48.3 45 105 86
125×100 139.7 133 114.3 108 124 117
125×90 139.7 - 101.6 - 124 114
125×80 139.7 133 88.9 89 124 111
125×65 139.7 133 76.1(73) 76 124 108
125×50 133 60.3 57 124 105
150×125 168.3 159 139.7 133 143 137
150×100 168.3 159 114.3 108 143 130
150×90 168.3 - 101.6 - 143 127
150×80 168.3 159 88.9 89 143 124
150×65 168.3 159 76.1(73) 76 143 121
200×150 219.1 219 168.3 159 178 168
200×125 219.1 219 139.7 133 178 162
200×100 219.1 219 114.3 108 178 156
200×90 219.1 - 101.6 - 178 152
200×200 273 273 219.1 219 216 208
200×150 273 273 168.3 159 216 194
200×125 273 273 139.7 133 216 191
200×100 273 273 114.3 108 216 184
300×250 323.9 325 273 273 254 241
300×200 323.9 325 219.1 219 254 229
300×150 323.9 325 168.3 159 254 219
300×125 323.9 325 139.7 133 254 216
350×300 355.6 377 323.9 325 279 270
350×250 355.6 377 273 273 279 257
350×200 355.6 377 219.1 219 279 248
350×150 355.6 377 168.3 159 279 238
400×350 406.4 426 355.6 377 305 305
400×300 406.4 426 323.9 325 305 295
400×250 406.4 426 273 273 305 283
400×200 406.4 426 219.1 219 305 273
400×150 406.4 426 168.3 159 305 264
450×400 457.2 478 406.4 426 343 330
450×350 457.2 478 355.6 377 343 330
450×300 457.2 478 323.9 325 343 321
450×250 457.2 478 273 273 343 308
450×200 457.2 478 219.1 219 343 298
500×450 508 529 457.2 478 381 368
500×100 508 529 406.4 426 381 356
500×350 508 529 355.6 377 381 356
500×300 508 529 323.9 325 381 346
500×250 508 529 273 273 381 333
500×200 508 529 219.1 219 381 324
550×500 559 - 508 - 419 406
550×450 559 - 457 - 419 394
550×400 559 - 406 - 419 381
600×550 610 - 559 - 432 432
600×550 610 630 508 530 432 432
600×450 610 630 457 480 432 419
650×600 660 - 610 - 495 483
650×550 660 - 559 - 495 470
650×500 660 - 508 - 495 457
700×650 711 - 660 - 521 521
700×600 711 720 610 630 521 508
700×550 711 - 559 - 521 495
750×700 762 - 711 - 559 546
750×650 762 - 660 - 559 546
750×600 762 - 610 - 559 533
800×750 813 - 762 - 597 584
800×700 813 820 711 720 597 572
800×650 813 - 660 - 597 572
850×800 864 - 813 - 635 622
850×750 864 - 762 - 635 610
850×700 864 - 711 - 635 597
900×850 914 - 864 - 673 660
900×800 914 920 813 820 673 648
900×750 914 - 762 - 673 635
950×900 965 - 914 - 711 711
950×850 965 - 864 - 711 698
950×800 965 - 813 - 711 686
1000×950 1016 - 965 - 749 749
1000×900 1016 1020 914 920 749 737
1000×8500 1016 - 864 - 749 724
1000×1000 1067 - 1016 - 762 711
1050×950 1067 - 965 - 762 711
1050×900 1067 - 914 - 762 711
1100×1050 1118 - 1067 - 813 762
1100×1000 1118 1120 1016 1020 813 749
1100×950 1118 - 965 - 813 737
1150×1100 1168 - 1118 - 851 800
1150×1050 1168 - 1067 - 851 787
1150×1000 1168 - 1016 - 851 775
1200×1150 1220 - 1168 - 889 838
1200×1100 1220 1220 1118 1120 889 838
1200×1050 1220 - 1067 - 889 813

Reference

Just before the final delivery, our merchandise are stringently checked by a team of quality analyzers on varied parameters, which guarantee their flawlessness and durability. In addition, clients can avail these goods from us at competitive rates.

ASTM

JIS

EURO

FAQ FAQ

Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe. Pipes and pipe fittings are made of a variety of materials, depending on the fluid or gas being transported. Most pipe fittings tend to be either threaded or able to slip over the pipes they connect. Whether you are using steel pipes of PVC pipes, a chemical solvent is required to create a seal between the pipe and the fittings.

Measure the required length of the pipe to be installed, keeping in mind the extra length required where the pipe will be inserted into the fitting. Mark this length on the pipe.

How to Calculate a Pipe Bend?

Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe. Pipes and pipe fittings are made of a variety of materials, depending on the fluid or gas being transported. Most pipe fittings tend to be either threaded or able to slip over the pipes they connect. Whether you are using steel pipes of PVC pipes, a chemical solvent is required to create a seal between the pipe and the fittings.

Measure the required length of the pipe to be installed, keeping in mind the extra length required where the pipe will be inserted into the fitting. Mark this length on the pipe.

Bevelled Ends

The ends of all buttweld fittings are bevelled, exceeding wall thickness 4 mm for austenitic stainless steel, or 5 mm for ferritic stainless steel. The shape of the bevel depending upon the actual wall thickness. This bevelled ends are needed to be able to make a “Butt weld”.

Welding Bevel acc.to ASME / ANSI B16.9 and ASME / ANSI B16.28

ASME B16.25 covers the preparation of buttwelding ends of piping components to be joined into a piping system by welding. It includes requirements for welding bevels, for external and internal shaping of heavy-wall components, and for preparation of internal ends (including dimensions and dimensional tolerances).

Beveld end

Our in-hourse R&D team developed bevel ends equipment are good using in thickness 2mm to 20mm pipe fittings, guarantee high efficiency and high quality.

These weld edge preparation requirements are also incorporated into the ASME standards (e.g., B16.9, B16.5, B16.34).

ASME B16.25 (BUTT WELD ENDS)

ASME B16.25 sets standards for the preparation of the ends of components that need to be welded together.

Cut square or slight chamfer, at manufacturer’s option for :

Buttweld Fittings general

A pipe fitting is defined as a part used in a piping system, for changing direction, branching or for change of pipe diameter, and which is mechanically joined to the system.

There are many different types of fittings and they are the same in all sizes and schedules as the pipe.

ASME / ANSI B16.9 dimension

ASME B16.9 Standard covers overall dimensions, tolerances,ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1⁄2 through NPS 48 (DN 15 through DN 1200).

Download PDF
Nominal Outside Diameter 90° Elbows 45° Elbows 180° Returns
Pipe Size
Long Radius Short Radius Long Radius Long Radius
(inches) (mm) (inches) Center to Face Center to Face Center to Face Radius Center to Center Back to face
(inches) (inches) (inches) (inches) (inches) (inches)
1/2 21.3 0.84 1.5 5/8 2 1.875
3/4 26.7 1.05 1.125 7/16 2.25 1.6875
1 33.4 1.315 1.5 1 7/8 3 2.1875
1.25 42.2 1.66 1.875 1.25 1 3.75 2.75
1.5 48.3 1.9 2.25 1.5 1.125 3 4.5 3.25
2 60.3 2.375 3 2 1.375 4 6 4.1875
2.5 73 2.875 3.75 2.5 1.75 5 7.5 5.1875
3 88.9 3.5 4.5 3 2 6 9 6.25
3.5 101.6 4 5.25 3.5 2.25 7 10.5 7.25
4 114.3 4.5 6 4 2.5 8 12 8.25
5 141.3 5.563 7.5 5 3.125 10 15 10.3125
6 168.3 6.625 9 6 3.75 12 18 12.3125
8 219.1 8.625 12 8 5 12 24 16.3125
10 273.1 10.75 15 10 6.25 15 30 20.375
12 323.9 12.75 18 12 7.5 18 36 24.375

Tolerances of Welded Fittings

NOMINAL PIPE SIZE NPS ANGULARITY TOLERANCES ANGULARITY TOLERANCES
Size Off Angle Q Off Plane P
½ to 4 0.03 0.06
5 to 8 0.06 0.12
10 to 12 0.09 0.19
14 to 16 0.09 0.25
18 to 24 0.12 0.38
26 to 30 0.19 0.38
32 to 42 0.19 0.5
44 to 48 0.18 0.75

All dimensions are given in inches. Tolerances are equal plus and minus except as noted.

  1. Out-of-round is the sum of absolute values of plus and minus tolerance.
  2. This tolerance may not apply in localized areas of formed fittings where increased wall thickness is required to meet design requirements of ASME B16.9.
  3. The inside diameter and the nominal wall thicknesses at ends are to be specified by the purchaser.
  4. Unless otherwise specified by the purchaser, these tolerances apply to the nominal inside diameter, which equals the difference between the nominal outside diameter and twice the nominal wall thickness.

The ASME B16.9 pipe fittings can be used under the jurisdiction of the ASME Boiler & Pressure Vessel Code (BPVC) as well as the ASME Code for pressure piping. Referencing pressure ratings of flanges per ASME B16.5, they can be designated as Classes 150, 300, 600, 900, 1500 and 2500. The allowable pressure ratings for ASME B16.9 pipe fittings may be calculated as for straight seamless pipe of equivalent material in accordance with the rules established in the applicable sections of ASME B31 Code for pressure piping.

Design of Fittings

The design of butt welding pipe fittings made to ASME B16.9 shall be established by one of the following methods: (a) mathematical analyses contained in pressure vessel or piping codes; (b) proof testing; (c) experimental stress analysis with hydrostatic testing to validate experimental results; (d) detailed stress analysis with results evaluation.

Standard Marking

Generally, ASME B16.9 pipe fittings shall be marked to show the following details: “trademark + material grade + wall thickness + size + heat number”. For example, “M ASTM A234 WP5 SCH80 6″ 385“. When steel stamps are used, care shall be taken so that
the marking is not deep enough or sharp enough to cause cracks or to reduce the wall thickness of the fitting below the minimum allowed.

Material & Manufacture

The ASME B16.9 fittings may be made from an extensive range of mateirals covering (1) carbon and low-alloy steels in accordance with ASTM A234 and ASTM A420; (2) austenitic and duplex stainless steels in accordance with ASTM A403 and ASTM A815; (3) nickel alloys in accordance with ASTM B366; (4) aluminum alloys in accordance with ASTM B361; and (5) titanium alloys in accordance with ASTM B363.

ASME B16.9

Pipe Fittings Dimensions Tolerance as per ASME B16.9:

Sizes 1/2″ – 48″

  • ASME / ANSI B16.9 Butt Weld Elbow – Long Radius
  • ASME / ANSI B16.9 Butt Weld Elbow – Short Radius
  • ASME / ANSI B16.9 Butt Weld Reducing Elbow
  • ASME / ANSI B16.9 Butt Weld 45° Elbow
  • ASME / ANSI B16.9 Butt Weld Fabricated Tee
  • ASME / ANSI B16.9 Butt Weld Reducer
  • ASME / ANSI B16.9 Butt Weld Concentric Reducer
  • ASME / ANSI B16.9 Butt Weld Eccentric Reducer
  • ASME / ANSI B16.9 Butt Weld 3D Elbow
  • ASME / ANSI B16.9 Butt Weld Stub Ends
  • ASME / ANSI B16.9 Butt Weld Cross
  • ASME / ANSI B16.9 Butt Weld Reducing Cross
  • ASME / ANSI B16.9 Butt Weld Tees
  • ASME / ANSI B16.9 Butt Weld End Cap
  • ASME / ANSI B16.9 Butt Weld Coupling
  • ASME / ANSI B16.9 Butt Weld Pipe Nipple
  • ASME / ANSI B16.9 Butt Weld 5D Elbow
  • ASME / ANSI B16.9 Butt Welded Pipe Fittings
Reducer applications

Applications

A steel pipe reducer is a component used in the pipelines to reduce its size from large to small bore in accordance to the inner diameter.

The length of the reduction here is equal to an average of the smaller and larger pipe diameters. Here, the reducer can be used as a diffuser or a nozzle. The reducer helps in meeting the existing piping of varied sizes or hydraulic flow of the piping systems. The usage of a steel reducer is carried out in the chemical factories and power plants. It makes the piping system reliable and compact. It safeguards the piping system from any kind of adverse impact or thermal deformation. When it is on the pressure circle, it prevents from any type of leakage and is easy to install. The nickel or chrome coated reducers extends the product life, useful for high vapor lines, and prevents corrosion.

  • Pipe Reducer
  • Hydraulic system
  • Pneumatic system
  • Pharmaceutical fittings
  • Air brake fittings
  • Gas fittings
  • Refrigerant fittings
  • Changing the piping diameter
  • Handling the expansion, misalignment or vibration problem
Standard Standard

Standard

Pipe fitting dimensions are in either metric or Standard English.

Because pipe fitting covers Pipe Fitting Dimensions several aspects, only the most common pipe fitting sizes can be given here. The most applied version is the 90° long radius and the 45° elbow, while the 90° short radius elbow is applied if there is too little space. The function of a 180° elbow is to change direction of flow through 180°. Both, the LR and the SR types have a center to center dimension double the matching 90° elbows. These fittings will generally be used in furnesses or other heating or cooling units.

Some of the standards that apply to buttwelded fittings are listed below. Many organizations such as ASME, ASTM, ISO, MSS, etc. have very well developed standards and specifications for buttwelded fittings. It is always up to the designer to ensure that they are following the applicable standard and company specification, if available, during the design process.

Some widely used pipe fitting standards are as follows:

ASME: American Society for Mechanical Engineers
This is one of the reputed organizations in the world developing codes and standards.
The schedule number for pipe fitting starts from ASME/ANSI B16. The various classifications of ASME/ANSI B16 standards for different pipe fittings are as follows:

ASTM International: American Society for Testing and Materials
This is one of the largest voluntary standards development organizations in the world. It was originally known as the American Society for Testing and Materials (ASTM).

AWWA: American Water Works Association

AWWA About – Established in 1881, the American Water Works Association is the largest nonprofit, scientific and educational association dedicated to managing and treating water, the world’s most important resource.

ANSI: The American National Standards Institute

ANSI is a private, non-profit organization. Its main function is to administer and coordinate the U.S. voluntary standardization and conformity assessment system. It provides a forum for development of American national standards. ANSI assigns “schedule numbers”. These numbers classify wall thicknesses for different pressure uses.

MSS STANDARDS: Manufacturers Standardization Society
The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry is a non-profit technical association organized for development and improvement of industry, national and international codes and standards for: Valves, Valve Actuators, Valve Modification, Pipe Fittings, Pipe Hangers, Pipe Supports, Flanges and Associated Seals

Difference between “Standard” and “Codes”:

Piping codes imply the requirements of design, fabrication, use of materials, tests and inspection of various pipe and piping system. It has a limited jurisdiction defined by the code. On the other hand, piping standards imply application design and construction rules and requirements for pipe fittings like adapters, flanges, sleeves, elbows, union, tees, valves etc. Like a code, it also has a limited scope defined by the standard.

Factors affecting standards: “Standards” on pipe fittings are based on certain factors like as follows:

BSP: British Standard Pipe

BSP is the U.K. standard for pipe fittings. This refers to a family of standard screw thread types for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread. This has been adopted internationally. It is also known as British Standard Pipe Taper threads (BSPT )or British Standard Pipe Parallel (Straight) threads (BSPP ). While the BSPT achieves pressure tight joints by the threads alone, the BSPP requires a sealing ring.

JIS: Japanese Industrial Standards

This is the Japanese industrial standards or the standards used for industrial activities in Japan for pipe, tube and fittings and published through Japanese Standards Associations.

NPT: National Pipe Thread

National Pipe Thread is a U.S. standard straight (NPS) threads or for tapered (NPT) threads. This is the most popular US standard for pipe fittings. NPT fittings are based on the internal diameter (ID) of the pipe fitting.

BOLTS & NUTS

We are manufacturer of Flange bolts & Nuts and supply high quality

AN: Here, “A” stands for Army and “N” stands for Navy

The AN standard was originally designed for the U.S. Military. Whenever, a pipe fitting is AN fittings, it means that the fittings are measured on the outside diameter of the fittings, that is, in 1/16 inch increments.

For example, an AN 4 fitting means a fitting with an external diameter of approximately 4/16″ or ¼”. It is to be noted that approximation is important because AN external diameter is not a direct fit with an equivalent NPT thread.

Dash (-) size

Dash size is the standard used to refer to the inside diameter of a hose. This indicates the size by a two digit number which represents the relative ID in sixteenths of an inch. This is also used interchangeably with AN fittings. For example, a Dash “8” fitting means an AN 8 fitting.

ISO: International Organization for Standardization

ISO is the industrial pipe, tube and fittings standards and specifications from the International Organization for Standardization. ISO standards are numbered. They have format as follows:

“ISO[/IEC] [IS] nnnnn[:yyyy] Title” where

General standard

Standard Specification
ASTM A234 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Moderate and High Temperature Service
ASTM A420 Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
ASTM A234 WPB ASTM A234 WPB refers to a specific grade of carbon steel pipe fittings, which are widely used in pressure piping and pressure vessel fabrication for service at moderate and elevated temperatures.
ASME B16.9 ASME B16.9 Standard covers overall dimensions, tolerances,ratings, testing, and markings for factory-made wrought buttwelding fittings in sizes NPS 1⁄2 through NPS 48 (DN 15 through DN 1200).
ASME B16.28 ASME B16.28 Standard covers ratings, overall dimensions, testing, tolerances, and markings for wrought carbon and alloy steel buttwelding short radius elbows and returns.
MSS SP-97 MSS SP-97 Standard Practice covers essential dimensions, finish, tolerances, testing, marking, material, and minimum strength requirements for 90 degree integrally reinforced forged branch outlet fittings of buttwelding, socket welding, and threaded types.
ASTM A403 Standard Specification for Wrought Austenitic Stainless Steel Piping Fittings.

Wide variety for all areas of application

DIN EN ASME
St 35.8 I
St 35.8 III
15 Mo 3
13 CrMo 4 4
10 CrMo 9 10
St 35 N
St 52.0
St 52.4
P235GH-TC1
P235GH-TC2
16Mo3
13CrMo4-5
10CrMo9-10
X10CrMoVNb9-1
P215NL
P265NL
L360NB
L360NE
P355N
P355NL1
P355NH
WPB
WPL6
WPL3
WPHY 52
WP11
WP22
WP5
WP9
WP91
WP92

Delivery

Inspection

Visual Inspection is conducted on fittings to check any surface imperfections. Both fittings body and weld are checked for any visible surface imperfections such as dents, die marks, porosity, undercuts, etc. Acceptance as per applicable standard.

ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers
ASTM A234 WPB eccentric reducers

Packing

For packing of carbon steel flanges with painting,we would use the bubble wrap to protect the painting.For flanges without painting or oiled with long-term shipment,we would suggest client to use the anti-tarnish paper and plastic bag to prevent the rust.

【H】 Ceramic lined pipe

Ceramic lined pipe is made through self-propagating high-temperature synthesis (SHS) technique.

【H】 Cast basalt lined steel pipe

Cast basalt lined steel pipe is composed by lined with cast basalt pipe, outside steel pipe and cement mortar filling between the two layers.

【H】 Ceramic Tile Lined Pipes

Ceramic tile lined pipes have very uniform coating of specially formulated ceramic material that is affixed to the inner of the pipe.

【H】 Rare earth alloy wear-resistant pipe

The material of the rare earth alloy wear-resistant pipe is ZG40CrMnMoNiSiRe, which is also the grade of rare earth alloy steel.

【H】 Tubes Erosion Shields

Tubes Erosion Shields are used to protect boiler tubing from the highly erosive effects of high temperatures and pressures thereby greatly extending tube life.

【H】 ASTM A213 T91 Alloy Tube

The ASTM A213 T91 seamless tubes are primarily used for boiler, superheater, and heat-exchanger.