Stub End

Why Choose Us

Factory Strength

Shanghai KEK Pipeline Technology Co., Ltd. is a reputable AAA listed pipe fittings manufacturer in China, covering an area of 66666㎡ (80000+㎡ in Phase II), with more than 30 technicians and engineers.

Our Certifications

KEK has obtained ISO9001, ISO14001, ISO18001, CE/PED, API certification and TS pressure pipe component special equipment manufacturing license, as well as Russia's EAC continuous certification.

Advanced Equipment

It has a full set of the largest and most advanced equipment in China, including a 4000-ton hydraulic press and a 3000-ton three-way cold extrusion molding machine.

Product Traceability

Product traceability, all products are numbered and indexed by furnace number, production process number, and RT inspection number to ensure the unique traceability of the product.

What is Stub End

A stub end, also known as a lap joint flange, is a type of pipe fitting that is used to connect pipes of different materials or sizes. It is widely used in various industries, such as oil and gas, petrochemicals, and water treatment. The main purpose of a stub end is to provide an efficient and flexible connection between pipes, allowing for easy installation, maintenance, and repair. In this article, we will explore the important aspects of a stub end and its various applications in different industries.

Carbon Steel Stub End
Product Name: carbon steel Stub end
Dimension and Wall Thickness
Seamless: 1/2”~24” (DN15~DN600) SCH5~SCH XXS
End connection：PE or BE
Marking： according to customer’s...
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Lap Joint Stub End Long Pattern
Product Name: Lap joint stub end long pattern
Dimension and Wall Thickness
Seamless: 1/2”~24” (DN15~DN600) SCH5~SCH XXS
End connection：PE or BE
Marking： according to...
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Lap Joint Stub End Short Pattern
Product Name: Lap joint stub end short pattern
Dimension and Wall Thickness：
Seamless: 1/2”~24” (DN15~DN600) SCH5~SCH XXS
End connection：PE or BE
Marking： according to...
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Stainless Steel Stub End
Product Name: Stainless steel Stub end
Dimension and Wall Thickness
Seamless: 1/2”~24” (DN15~DN600 SCH5~SCH XXS
End connection：PE or BE
Marking： according to...
read more
Alloy Steel Stub End
Product Name: Alloy steel Stub end
Dimension and Wall Thickness
Seamless: 1/2”~24” (DN15~DN600) SCH5~SCH XXS
End connection：PE or BE
Marking： according to customer’s...
read more

Benefits of Stub End

Facilitating Easy Installation and Maintenance
Stub Ends are known for their versatility in joining pipes with different outside diameters. This makes them a go-to solution for situations where the connection of pipes with identical diameters is impractical. The ease of installation and maintenance makes Stub Ends a favorite among engineers and technicians.

Providing Flexibility in Piping Systems
The ability to connect pipes of varying sizes adds flexibility to piping systems. This is particularly valuable in industries where process requirements may change, and modifications to the piping layout become necessary. Stub Ends enable quick and efficient adaptations without the need for extensive rework.

Minimizing Stress and Vibration
The loose backing flange of the Stub End allows for rotational movement, reducing stress and vibration in the piping system. This is especially crucial in applications where thermal expansion and contraction are common, ensuring the longevity of the entire piping infrastructure.

Creating Leak-Proof Joints
The welding of the main body of the Stub End to the pipe results in a robust and leak-proof joint. Additionally, the bolted connection with the backing flange enhances the overall integrity of the joint, providing a reliable solution for preventing leaks in critical industrial processes.

Meeting Specific Industry Standards
Stub Ends are available in various materials and specifications, allowing them to meet the diverse standards required in different industries. Whether it's for chemical processing, oil and gas, or water treatment, Stub Ends can be customized to comply with specific project requirements.

Types of Stub End

The type A stub end is used for standard lap joint flange. The lap thickness on the stub end is greater than or equal to the nominal thickness of pipe wall. In addition, the outer corner radius of the type A can receive the lap joint flange. The inside corner is square. Lap usually has a machined serrated face.

The type B stub end is used for standard slip on flanges as lap flanges. The lap thickness on these short ends is greater than or equal to the nominal thickness of pipe wall. Also, the outer corner radius of type B is small enough to receive the slip o flange that can be used as a backup flange. The inner corner is square. Lap usually has a machined serrated face.

The type C stub end can be used for standard lap joint flange and slip on flange. It is flared leaving a rounded edge at the inside diameter of the lap. If necessary, the radius can be made closed to a square. The lap thickness is 75% of the pipe wall. The type C is very short enough to accommodate any backup flange. The lap joint on type C is smooth, and it is not machine.

Application of Stub End

Pipe Connections

Stub ends are commonly used to connect pipes of different materials or sizes. They provide a flexible connection that allows for easy alignment and adjustment during installation. This makes them particularly useful in situations where pipes need to be connected or disconnected frequently, such as in temporary installations or maintenance operations.

Transition Joints

Stub ends are also used as transition joints to connect pipes of different materials. This is particularly useful in situations where the joining of two different materials is required, such as in pipelines carrying different types of fluids or in systems with different operating temperatures. Stub ends provide a smooth transition between the two materials, ensuring a leak-free connection.

Flange Connections

The flange on a stub end allows for easy connection with the flange on the other pipe. This provides a secure and reliable connection that can withstand high pressure and temperature conditions. Stub ends with raised face flanges are often used in applications where a tight seal is required, such as in pipeline systems carrying corrosive or hazardous fluids.

Piping Systems

Stub ends are an integral part of piping systems in various industries, such as oil and gas, chemical, and water treatment. They are used in a wide range of applications, including process piping, fire protection systems, and HVAC (heating, ventilation, and air conditioning) systems. Stub ends provide a reliable and efficient connection that allows for the smooth flow of fluids or gases.

How to Choose Stub End

Corrosion Resistance

The choice of material should be based on its resistance to corrosion, taking into account the type of fluid or gas being transported and the surrounding environment.

Temperature and Pressure Ratings

The material must have suitable temperature and pressure ratings to withstand the operating conditions of the piping system without any deformations or failures.

Chemical Compatibility

Compatibility with the fluids or gases being transported is crucial to avoid any reactions or degradation of the stub end flange material.

Mechanical Strength

The material should possess adequate mechanical strength to withstand the forces and stresses exerted on it during operation, including pressure, vibration, and thermal expansion.

Cost and Availability

Considering the project budget and the availability of the material is important for the overall feasibility of the piping system.

Material of the Stub End

01/

Carbon Steel
Carbon steel is the most widely used material for stub end flanges due to its excellent mechanical properties, affordability, and compatibility with most piping systems. It offers good corrosion resistance and high tensile strength, making it suitable for various applications.

02/

Stainless Steel
Stainless steel is often preferred for stub end flanges in industries where corrosion resistance is crucial. It contains a high percentage of chromium, which forms a protective oxide layer on the surface, providing excellent resistance to rust and corrosion. Stainless steel stub end flanges are commonly used in chemical, food processing, and pharmaceutical industries.

03/

Alloy Steel
Alloy steel stub end flanges are specifically designed to withstand high temperatures and pressures. They are made by adding various alloying elements such as chromium, molybdenum, or nickel to enhance their mechanical properties. Alloy steel stub end flanges find applications in industries such as power generation, oil and gas, and petrochemicals.

04/

PVC (Polyvinyl Chloride)
PVC stub end flanges are suitable for non-corrosive applications where low cost and easy installation are essential. PVC is a lightweight and chemically resistant material, making it ideal for applications involving water, wastewater, and irrigation systems.

05/

HDPE (High-Density Polyethylene)
HDPE stub end flanges are commonly used in piping systems for their excellent resistance to chemicals, abrasion, and corrosion. They are widely used in industries dealing with aggressive fluids or gases, such as mining, water treatment, and chemical processing.

06/

CPVC (Chlorinated Polyvinyl Chloride)
CPVC stub end flanges are known for their high temperature resistance and excellent fire performance. They are commonly used in industries where hot water or corrosive chemicals are involved, such as plumbing, heating, and process piping.

Stub End Installation and Precautions

Proper Stub-End Length

When installing Lap Joint Flanges, the proper length of the stub-end is crucial. The length should be sufficient to provide proper support to the flange and ensure a secure joint.Incorrect stub-end length can result in misalignment and leakage, undermining the efficiency of the system. It's important to adhere to recommended guidelines for stub-end dimensions to avoid potential issues.The two most commonly referenced specifications for stub end companionship to lap joints are the MSS type (short-length pattern) and the ASA type (long-length pattern).

Bolt and Gasket Selection

The selection of bolts and gaskets for Lap Joint Flanges requires careful consideration. Bolts must be of appropriate length to ensure proper engagement and clamping force.Gaskets should be compatible with the materials and operating conditions of the system to prevent leaks. Collaborating with professionals who understand the specific requirements of Lap Joint Flanges can help ensure the right choices are made.

Step-By-Step Guide: How to Properly Install Stub Ends for Stub End

Gather the Necessary Tools and Materials
Before you begin the installation process, make sure you have all the required tools and materials on hand.

Prepare the Pipe Ends
Start by cleaning and preparing the pipe ends where the stub ends will be installed. Ensure that the pipe ends are free of dirt, debris, and any contaminants that could compromise the sealing integrity of the connection. Use a wire brush or emery cloth to remove any corrosion or oxidation from the pipe surface.

Insert the Stub Ends
Slide the stub ends onto the pipe ends, ensuring that they are positioned correctly and securely. The length of the stub end should be sufficient to accommodate the lap joint flange and gasket assembly. Make sure that the stub ends are aligned properly with the pipe ends to prevent misalignment during installation.

Install the Gaskets
Place the appropriate gaskets between the stub ends and lap joint flanges. Ensure that the gaskets are centered and properly seated to provide an effective seal. Use gaskets made from suitable materials compatible with the fluid or gas being transported through the pipeline.

Position the Lap Joint Flanges
Position the lap joint flanges over the stub ends and align them with the pipe ends. Make sure that the flange bolt holes are properly aligned with the bolt holes on the stub ends. Use alignment tools or shims if necessary to achieve proper alignment and ensure a tight fit.

Insert Bolts and Nuts
Insert bolts through the bolt holes on the lap joint flanges and stub ends, securing them in place with nuts. Tighten the bolts evenly and gradually in a crisscross pattern to ensure uniform compression of the gaskets and prevent distortion of the flange faces. Use a torque wrench to tighten the bolts to the specified torque values recommended by the flange manufacturer.

Check for Leaks
Once the bolts are tightened to the correct torque, visually inspect the connection for any signs of leakage. Perform a leak test by pressurizing the pipeline and applying a soap solution to the joint area. If bubbles form, indicating a leak, carefully retighten the bolts as necessary until the leakage stops.

Final Inspection and Testing
After completing the installation, perform a final inspection of the entire connection to ensure that all components are properly installed and secured. Verify that the bolts are tightened to the specified torque and that there are no visible signs of damage or misalignment. Conduct any additional testing or inspections required by applicable regulations or industry standards.

Our Factory

Shanghai KAIKE Pipe Technology Co., Ltd. is a reputable AAA listed pipe fittings manufacturer in China,covering an area of 66666㎡ (80000+ ㎡in stage II) and with technician and engineers more than 30 personal. Kaike Group is made up of Shanghai Kaike Piping Technology, Shanghai Kaike Valve manufacture and one export company Shanghai Chainmill Industry, they are all based in Shanghai, which the economic center of China. KAIKE has reached up to an annual output of pipe fittings of 20,000 tons.KAIKE has the ability to produce by various materials like carbon (low temperature) steel, stainless steel, duplex steel, alloy steel, nickel base alloy and special materials as requested according to GB, SH, Hg, JB, SY, ASME/ANSI, MSS, JIS, DIN, BS,GOST etc.Its main products include BW pipe fittings(SMLS or welded), steel flange, forged pipe fittings as well as prefabricated spools and manifolds,and also can produce according to customers' drawings and requirements.

Certificate

FAQ

Q: What is a stub end?

A: Used in conjunction with a backing flange, a Stub End is, essentially, a short length of pipe with one flared end and one square-cut end, which is welded to a pipe of the same NPS, material grade and schedule. The combination of a Stub End and a backing flange is generally used as an alternative to a standard flange.

Q: What is the difference between stub end and flange?

A: A Stub End adapter slides thru the Flange and is welded to the pipe. The Lap Joint Flange is similar to the Slip On Flange except it is flat across the face and has a radius machined at the bore. This allows it to rotate freely around the Stub for easy alignment to the mating Flange.

Q: What is the difference between MSS and ASA stub ends?

A: The ASA-type stub end is of a longer length and is less common than the MSS type, though it may be more suitable for your application. MSS Type A stub ends are the industry norm and are utilized with standard flat-face lap joint flanges.

Q: How to make a stub end?

A: Stub ends and lap joint flanges can be assembled following this process: The lap flange is slipped over and onto the stub end flange. The stub end flange is then welded onto a pipe spool, using an approved Welding. Procedure specification (WPS), by a qualified welder.

Q: What is the difference between a stub flange and a flange adapter?

A: Flange adapters differ from stub-ends by their overall length. A flange adapter is longer, allowing it to be clamped in a fusion machine similar to a pipe end.Type A and B stub end are similar to forged fittings, such as elbows and tees, and type C stub end are made in customized sizes.

Q: Why is the stub end used?

A: The main function of stub end is to connect pipes together in a piping system along with a stainless steel lap joint flange/backing flange. The stainless steel stub ends are used in conjunction with stainless steel lap joint flanges/backing flanges.

Q: Why a lap flange and stub end would be used instead of a weld neck flange?

A: The lap-joint flange and stub-end assembly are used mainly in piping systems that necessitate frequent dismantling for inspection or routine maintenance. It is also used in the erection of large diameter or hard-to-adjust piping configurations because of its quick bolt hole alignment.

Q: What is the difference between long pattern and short pattern stub ends?

A: Stub end include long or short pattern length. The end of long pattern is also known as ASA Stub Ends. The short end is used with the larger flanges of ANSI 300 and 600. They are commonly used in most sizes ANSI 900 and above.

Q: Is a slip on flange the same as a lap joint flange?

A: lap joint flanges are very similar to a slip-on flange, with the main difference being that it has a curved radius at the bore and face to house a lap joint stub-end. Lap joint flanges and stub-end assemblies are typically used in situations where frequent dismantling is required for for inspection.

Q: How much gap do you need for a slip on flange?

A: "The slip-on flange is positioned so the inserted end of the pipe or fitting is set back or short of the flange face by the thickness of the pipe wall plus 1/8 of an inch. This allows for a fillet weld inside the SO flange equal to the thickness of the pipe without doing any damage to the flange face.

Q: Why is stub used?

A: Stubs are small pieces of code that take the place of another component during testing. The benefit of using a stub is that it returns canned results and answers, making the test easier to write. You can run your tests even if the other component isn't working yet.

Q: What are the different types of stub ends?

A: Stub Ends are available in two lengths, MSS and ANSI. Jero also offers special lengths as required by our customers. MSS - MSS is the standard length Stub End. ANSI - ASA is the long length Stub End.

Q: What is a stub flange?

A: PE Stub Flanges and Backing rings provide a flange connection point in PE pipe systems. Stub flanges are available in a range of pressure classes, with either a short spigot for butt welding or a long spigot for both butt welding or electrofusion welding.

Q: What is the difference between a spigot flange and a slip flange?

A: Spigot Flange – While slip flanges fit over PVC or CPVC pipe, spigot flanges fit into a PVC or CPVC fitting. These are great for giving a slip fitting a flanged end. Like slip flanges, these require solvent cement for installation.

Q: What is the purpose of a stub out in plumbing?

A: Stub outs are greywater collection plumbing which dead ends at a cap. They provide for for easy diversion of graywater to a future graywater system to be made during the construction of a house, without having to install the complete graywater system.

Q: What is the function of a stub flange?

A: HDPE stub flanges are used in piping as part of a fitting for the purpose of redirecting or changing pipes diameter. They are usually produced during the process of casting machinery components and molding.

Q: What is the difference between Type A and Type B stub ends?

A: Under certain design criteria such as temperature or pressure, it is not acceptable to have the joint between stub end and pipe in close proximity with the flange joint, in these applications ANSI types are used. Type A stub ends are used with lap joint flanges. Type B stub ends are used with slip-on flanges.

Q: What is the purpose of a stub end?

Q: What is the difference between a lap flange and a slip on flange?

Q: What type of flange is used with a stub end?

A: Lap Joint Flanges
A Stub end Flange or more commonly called Lap Joint Flanges are used with Stub Ends. A Stub End adapter slides thru the Flange and is welded to the pipe. The Lap Joint Flange is similar to the Slip On Flange except it is flat across the face and has a radius machined at the bore.

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