How to weld olets?

Welding Olets have become crucial in various industrial applications, particularly in the oil, gas, and petrochemical industries. These fittings enable seamless branching connections between pipelines while maintaining their integrity and ensuring a leak-free operation. This article will provide a detailed understanding of how to weld outlets, including the materials required, the best practices, and essential safety measures.

What is an olet?

An olet (also known as an outlet) provides a branch from a large diameter pipeline to a small diameter pipeline. The pipeline welded onto the branch pipe is called the main pipe, and the pipeline welded onto the branch pipe is called the branch pipe. It has outstanding advantages such as safety and reliability, cost reduction, simple construction, improved medium flow channels, series standardization, and convenient design and selection. It is increasingly widely used in high-pressure, high-temperature, large-diameter, and thick wall pipelines, replacing traditional branch pipe connection methods.

Types of Olets

The different types of olets include Weldolet, Sockolet, Thredolet, Sweepolet, Latrolet, Flangolet, Nipolet, Coupolet, Elbolet, Insert Weldolet, and Brazolet.
1. Weldolet
A Weldolet is a type of branch connection used in the piping industry. It is designed for connecting a smaller pipe to a larger pipe using a welding process. This ensures a strong, leak-proof connection, making it ideal for high-pressure applications.
2. Sockolet
Sockolet connections attach a smaller pipe to a larger pipe by inserting the smaller pipe into the larger pipe and securing it with a socket weld. This type of olet is suitable for moderate pressure and temperature applications.
3. Thredolet
A Thredolet type of olet creates a threaded connection between two pipes. This connection is made by threading the smaller pipe into the larger pipe, allowing for easy assembly and disassembly.
4. Sweepolet
Sweepolet fittings are designed to create a smooth, sweeping connection between a branch pipe and a run pipe. This design helps minimize turbulence and pressure drop in the piping system, making sweepolets suitable for high-velocity applications.
5. Latrolet
A Latrolet is a branch connection that provides a 45-degree lateral connection between two pipes. This type of olet is ideal for situations where space is limited or a specific angle is required.
6. Flangolet
Flangolets are used to create a flanged connection between two pipes. This type of olet is designed with a flange on one end and a weld bevel on the other, allowing for easy installation and removal.
7. Nipolet
A Nipolet combines a Weldolet and a Nipple, providing a threaded or socket-weld connection between two pipes. Nipolets are used when a full-sized olet is not necessary or space is limited.
8. Coupolet
Coupolets are used to create a coupling connection between two pipes. This type of olet is designed with a threaded or socket-weld connection on one end and a weld bevel on the other, making it easy to install and remove.
9. Elbolet
An Elbolet is an olet designed to connect a smaller pipe to a larger pipe at a 90-degree angle. This type of olet is ideal for situations where a specific angle is required, or space is limited.
10. Insert Weldolet
Insert Weldolet is a unique branch connection designed to be inserted into the main pipe and welded in place. This type of olet provides a strong, leak-proof connection and is suitable for high-pressure applications.
11. Brazolet

A Brazolet is an olet that creates a brazed connection between two pipes. This connection is made by heating the pipes and applying a filler metal, which cools and forms a strong bond.

How to Weld Olets: A Comprehensive Guide to Mastering the Technique

Welding various types of olets, such as weldolets, sockolets, thredolets, sweepolets, latrolets, flangolets, nipolets, coupolets, elbolets, insert weldolets, and brazolets, requires proper preparation, alignment, and welding techniques. By following the steps outlined in this comprehensive guide, you can ensure secure and efficient connections for your pipeline projects.

Welding materials and equipment

Before beginning the welding process, ensure you have the following materials and equipment:

• Olets: Select the appropriate size and material based on the pipeline’s specifications.
• Run pipe: The primary pipeline onto which the weldolets will be attached.
• Branch pipe: The secondary pipeline connected to the run pipe through the weldolet.
• Welding machine: Choose the right welding machine for the specific material and thickness of the pipes.
• Electrodes: Select the appropriate welding electrodes based on the pipes’ materials.
• Safety gear: Wear welding gloves, a welding helmet, safety glasses, and appropriate clothing.

Preparation

Before welding, it’s essential to prepare the surfaces of both the run pipe and olet. Follow these steps:

• Inspect the olet: Ensure the olet is free of defects, such as cracks, and is the correct size and material for the application.
• Clean the surfaces: Remove any dirt, rust, or oil from the surfaces of the run pipe and weldolet using a wire brush or grinder.
• Align the weldolet: Place the olet onto the run pipe, ensuring proper alignment and contact between the surfaces.
• Tack weld: Apply a few tack welds to secure the olet on the run pipe.

Welding Process

Follow these steps for welding the olets to the run pipe:

• Choose the welding technique: Depending on the pipe’s material and thickness, select the appropriate welding technique, such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW), or gas tungsten arc welding (GTAW).
• Weld the root pass: Start by welding the root pass, which is the first layer of the weld. Maintain a consistent arc length and travel speed to ensure proper penetration and fusion.
• Weld the remaining passes: After completing the root pass, weld the remaining passes using the same welding technique. The number of passes depends on the thickness of the pipe and weldolet.
• Inspect the weld: Inspect the weld for any defects, such as porosity, cracks, or lack of fusion. If necessary, use non-destructive testing methods like ultrasonic testing or radiographic testing.

Post-Welding Procedures

Once the welding is complete, follow these steps to ensure the connection’s quality and longevity:

• Clean the weld: Remove any slag, spatter, or other debris from the weld using a wire brush or grinder.
• Post-weld heat treatment: Depending on the material, post-weld heat treatment (PWHT) may be necessary to relieve stress and improve the weld’s mechanical properties.
• Coating and corrosion protection: Apply the appropriate coating and corrosion protection measures, such as painting or galvanizing, to protect the weld and surrounding areas from environmental factors and potential damage.

Safety Considerations

While welding olets, it is vital to follow safety precautions to minimize the risk of accidents and injuries. Here are some essential safety tips to consider:

• Personal Protective Equipment (PPE): Always wear appropriate PPE, including welding gloves, a welding helmet with a suitable shade, safety glasses, and flame-resistant clothing.
• Ventilation: Ensure proper ventilation in the welding area to prevent the buildup of harmful gases and fumes.
• Fire safety: Keep a fire extinguisher nearby, and remove any flammable materials from the welding area.
• Electrical safety: Inspect the welding equipment for any damage or wear and ensure all connections are secure to prevent electric shock hazards.
• Proper posture: Maintaining a comfortable and stable body position while welding reduces the risk of fatigue and strain injuries.

How to Weld Weldolets

Weldolets are the most common type of olet used for branch connections, offering a stable and secure connection. To weld a weldolet:

In general, the fitting is welded with a CJP groove weld with a reinforcing fillet weld. The CJP groove weld is flush to the edge of the first bevel if there is a compound bevel. The size of the reinforcing fillet is dependent on the specific pressure piping code specified by the Owner.
As far as the problem with the run pipe becoming oval and excessively distorted, the fewer weld passes to achieve the required weld size the better. Distortion is related to the number of weld beads. The more weld beads, the greater the distortion. You could try pre-cambering the run pipe before cutting the hole for the integrally reinforced branch fitting.
The branch fitting should be hand contoured by grinding to ensure a uniform root opening all around the branch fitting before tacking it into position. Most of the fittings are sized by the manufacturer to fit a range of run pipe diameters if the contractor takes the time needed to properly contour the fitting before welding it to the run pipe. Some contractors do not take the step of properly hand fit the branch fitting and then they complain when they don’t achieve the required CJP groove weld.

• Clean the surfaces: Ensure that the surface of the pipe and the weldolet is free from dirt, oil, or any contaminants.

• Align the weldolet: Position the weldolet on the run pipe, aligning the beveled edge with the pipe’s surface.

• Tack weld: Tack weld the weldolet, ensuring it remains aligned and level.

• Complete the weld: Using a suitable welding process, such as SMAW, GMAW, or GTAW, complete the weld around the entire circumference of the weldolet.

How to Weld Sockolets

Sockolets are used for smaller branch connections and feature a socket that fits over the end of the branch pipe. To weld a sockolet:

Prepare the branch pipe: Cut the end at a 45-degree angle and deburr the edge.

Clean the surfaces: Clean the sockolet and branch pipe surfaces to ensure proper fusion.

Insert the branch pipe: Slide the branch pipe into the sockolet’s socket, ensuring a snug fit.

Weld the connection: Using a suitable welding process, weld the joint between the branch pipe and the sockolet.

How to Weld Thredolets

Thredolets feature threaded connections and are often used for smaller pipe sizes or in applications where welding is impractical. To weld a thredolet:

• Thread the pipe: Cut threads on the end of the branch pipe, ensuring they match the threads of the thredolet.

• Apply thread sealant: Apply a suitable thread sealant to the threads of the branch pipe and thredolet.

• Thread the connection: Screw the branch pipe into the thredolet, ensuring a tight and secure connection.

How to Weld Sweepolets

Sweepolets offer a smooth flow transition from the run pipe to the branch pipe due to their curved shape. To weld a sweepolet:

• Clean the surfaces: Clean the surfaces of the run pipe and sweepolet, ensuring proper fusion.

• Align the sweepolet: Position the sweepolet on the run pipe, aligning its contour with its surface.

• Tack weld: Tack weld the sweepolet, ensuring it remains aligned and level.

• Complete the weld: Weld the entire circumference of the sweepolet using an appropriate welding process.

How to Weld Latrolets

Latrolets are used for lateral connections, allowing for a 45-degree branch connection. To weld a latrolet:

• Clean the surfaces: Ensure that the surfaces of the run pipe and latrolet are free from dirt, oil, or any contaminants.

• Align the latrolet: Position the latrolet on the run pipe, aligning its beveled edge with its surface.

• Tack weld: Tack weld the latrolet, ensuring proper alignment and levelness.

• Complete the weld: Using a suitable welding process, weld the entire circumference of the latrolet to the run pipe.

How to Weld Flangolets

Flangolets are used to connect pipes to flanged connections. To weld a flangolet:

• Clean the surfaces: Clean the surfaces of the flangolet and the pipe, removing any dirt, oil, or contaminants.

• Align the flangolet: Position the flangolet onto the pipe, ensuring proper alignment with the flanged connection.

• Tack weld: Tack weld the flangolet, ensuring it remains aligned and level.

• Complete the weld: Weld the flangolet to the pipe using an appropriate welding process, ensuring a secure connection.

How to Weld Nipolets

Nipolets are used for branch connections where welding directly to the run pipe is not desired. To weld a nipolet:

• Prepare the branch pipe: Cut the branch pipe to the desired length and deburr the edge.

• Clean the surfaces: Clean the nipolet and branch pipe surfaces, ensuring proper fusion.

• Insert the branch pipe: Slide the branch pipe into the nipolet’s socket, ensuring a snug fit.

• Weld the connection: Using a suitable welding process, weld the joint between the branch pipe and the nipolet.

How to Weld Coupolets

Coupolets connect pipes to couplings, providing a secure and stable connection. To weld a coupolet:

• Clean the surfaces: Clean the surfaces of the coupolet and the pipe, removing any dirt, oil, or contaminants.

• Align the coupolet: Position the coupolet onto the pipe, ensuring proper alignment with the coupling.

• Tack weld: Tack weld the coupolet, ensuring it remains aligned and level.

• Complete the weld: Weld the coupolet to the pipe using an appropriate welding process, ensuring a secure connection.

How to Weld Elbolets

Elbolets are used for 90-degree branch connections, providing a secure and stable connection. To weld an elbolet:

• Clean the surfaces: Clean the elbolet and run pipe surfaces, ensuring proper fusion.

• Align the elbolet: Position the elbolet on the run pipe, aligning its beveled edge with the pipe’s surface.

• Tack weld: Tack weld the elbolet, ensuring proper alignment and levelness.

• Complete the weld: Using a suitable welding process, weld the entire circumference of the elbolet to the run pipe.

How to Weld Insert Weldolets

Insert weldolets are designed for high-pressure applications, providing a secure connection. To weld an insert weldolet:

• Clean the surfaces: Clean the surfaces of the insert weldolet and the run pipe, ensuring proper fusion.

• Align the insert weldolet: Position the insert weldolet on the run pipe, aligning its beveled edge with the pipe’s surface.

• Tack weld: Tack weld the insert weldolet, ensuring proper alignment and levelness.

• Complete the weld: Using a suitable welding process, weld the entire circumference of the insert weldolet to the run pipe, ensuring a secure connection.

How to Weld Brazolets

Brazolets are used for branch connections where brazing is the preferred method of joining. To weld a brazolet:

• Clean the surfaces: Clean the brazolet and the run pipe surfaces, ensuring proper fusion.

• Align the brazolet: Position the brazolet on the run pipe, aligning its beveled edge with its surface.

• Apply brazing flux to the joint between the brazolet and the run pipe.

• Heat the joint: Using a brazing torch, heat the joint until the flux becomes fluid and transparent.

• Apply filler metal: Apply the brazing filler metal to the joint, allowing it to flow into the joint by capillary action.

• Cool the joint: Allow the joint to cool naturally, forming a strong and secure connection.

I have a couple of questions regarding the use of a weldolet:

1. Are there any advantages of using a weldolet compared to a sweepolet?

WOL is cheaper and more commonplace to fabricate, and now that the patent has expired, they can be purchased from several different suppliers in many materials.

2. Are there any situations when one (weldolet or sweepolet) would be preferential?

If you have high loads, vibrations, or other forces on the branch or a thin wall pipe and your fitting size is > 50% of the run pipe, sweepolets may help. AFAIK, sweepolets are a custom fitting supplied by Bonney Forge. As they form part of the pipe, they need to be specifically manufactured to the same OD, wt, and material grade as the pipe; hence, they are unavailable “off the shelf.”

3. Any fabrication/operating issues with either?

Fabrication is relatively straightforward for both, and the operation is identical.

4. Any other methods of introducing a flushing branch onto the main pipe?

There is also a “weldoflange” made by Promat, up to 2″ branch size, which combines a standard flange with a weldolet as a single forged item avoiding one or two small welds. You could also use a reducing tee, which is quite unlikely for a pig trap.

More information on the main runner pipe is 168.3mm OD (6″), wall thickness is 12.7mm.

The flushing pipe is 2″.

It is more curiosity than anything for my own benefit. First time I have come across using WOLS and SOLS in a design.

The “weldoflange” is another option.

However, from my experience, I know these are very expensive. On a recent shell job, we purchased 1″ or 1.1/2″ of these weldoflanges. I called them flageolets.

They cost around 700 euros a piece, which is by far more than one would buy a weldolet + flange + pipe and weld those together.

Nipolets could be another solution to reduce one weld (the weld connecting the WOL to the adjacent pipe fitting).