What is orbital welding? How does orbital welding machine work?

Orbital welding is an automated welding process that uses specialized equipment to rotate the welding arc 360 degrees around a stationary workpiece, typically a pipe or tube. This process is called “orbital” because the welding arc orbits the workpiece. It is a highly precise and controlled method, often used in industries where weld quality and consistency are critical, such as in aerospace, semiconductor manufacturing, pharmaceuticals, and food and dairy industries.

The process involves using a machine that holds the welding head in place while the workpiece remains stationary. The welding parameters, such as the speed of the arc’s rotation, the heat input, and the shielding gas composition, are all programmatically controlled, which allows for high repeatability and consistency in the welds. This level of control makes orbital welding an ideal choice for applications where manual welding might not achieve the required precision or where access is limited.

Orbital welding is particularly advantageous for welding pipes and tubes in situ, such as in piping systems where the welds need to be of high integrity and free from defects like porosity or cracks, to ensure the system’s reliability and safety.

The orbital welding equipment are designed to automate the welding process, ensuring precision, consistency, and quality in welds, especially for tubular and piping systems.

Key components of an orbital welding equipments include:

1. Power Supply: The power supply for an orbital welding system is a specialized unit that not only provides the necessary current for welding but also controls various aspects of the welding process, such as arc voltage, current, and pulse parameters. It is often programmable to allow for the precise control of welding parameters for different welding applications.
2. Welding Head: The welding head is a critical component that houses the welding torch. It is designed to move around the pipe or tube, providing 360-degree weld coverage. There are different types of welding heads for different applications, including those for narrow spaces or specific diameters of pipes and tubes.
3. Wire Feeder (if applicable): In processes that require filler material, a wire feeder is used to feed the welding wire at a controlled rate into the weld pool. The wire feeder is synchronized with the movement of the welding head and the power supply parameters.
4. Shielding Gas Apparatus: Shielding gas is essential in protecting the weld pool from atmospheric contamination. The shielding gas apparatus includes a gas supply, regulators, and flow meters to ensure a consistent and appropriate flow of gas over the weld pool during the welding process.
5. Cooling System: High-intensity welding processes generate significant heat, which can damage equipment. Many orbital welding systems include a cooling system, often a water-cooling mechanism, to maintain the welding head and other components at safe operating temperatures.
6. Control System: The control system is the “brain” of the orbital welding system, allowing the operator to set and adjust welding parameters such as travel speed, arc gap control, and heat input. Advanced systems come with pre-programmed welding schedules or allow for custom programming to accommodate various welding specifications.
7. Camera and Monitoring System (optional): For high precision applications and to enhance quality control, some orbital welding systems are equipped with cameras and monitoring systems. These allow operators to closely monitor the welding process in real-time, often remotely, to ensure the weld quality meets the required standards.
8. Track or Guide System: This component supports the welding head and guides its movement around the pipe or tube. The design of the track or guide system ensures smooth, consistent motion that is crucial for achieving uniform welds.

9. Facing tubing machine

Facing tubing, also known as tube squaring or tube facing, is a critical preparatory process in industries where tubes and pipes are used, especially in high-purity or high-integrity welding applications such as semiconductor, biopharmaceutical, and aerospace industries. The process involves preparing the ends of tubes or pipes to ensure they are perfectly square and smooth before welding. This preparation is crucial for achieving high-quality, leak-free orbital welds.

Key aspects of facing tubing include:

• Squaring the Ends: The primary goal of facing is to ensure that the end of the tube or pipe is cut perpendicular to its axis. This squaring is essential for creating a proper alignment between adjoining tube or pipe ends, which in turn ensures a uniform weld bead and optimal weld strength.
• Removing Burrs: The facing process removes any burrs or irregularities from the tube end. Burrs can create points of weakness in the weld, potentially leading to cracks or leaks.
• Cleaning the Surface: Facing also involves cleaning the end of the tube or pipe to remove any oxides, dirt, or contaminants. A clean, oxide-free surface is crucial for achieving good weld quality, as contaminants can lead to weld defects like porosity or inclusions.
• Creating a Bevel (if required): For certain welding applications, a bevel may need to be created on the tube end to accommodate the welding process. This bevel, or chamfer, is designed to ensure proper penetration and fusion of the weld.

Tools and Equipment:

Facing tubing is performed using a range of tools and equipment, from simple hand tools for small jobs to sophisticated, automated machines for large-scale or high-precision applications. These tools ensure the process is carried out efficiently and accurately, providing the best possible preparation for welding.

Importance:

The quality of the weld in tubing applications is highly dependent on the quality of the tube end preparation. Inadequate preparation can lead to weld defects, reduced weld strength, and potential failures in service. Therefore, facing tubing is an essential step in the preparation of tubes and pipes for welding, particularly in applications where the purity and integrity of the weld are paramount.

      10 Purge gas panel in orbital welding

In orbital welding, a purge gas panel plays a crucial role in ensuring the quality and integrity of the weld, especially in materials like stainless steel, titanium, and other alloys that are sensitive to oxidation. The primary function of the purge gas panel is to control and supply an inert or semi-inert gas, typically argon or a mixture of argon and hydrogen, to the welding zone to protect it from atmospheric contamination during the welding process.

Components and Functions:

1. Gas Supply: The purge gas panel is connected to a source of high-purity inert gas, commonly argon, which is used to displace air and moisture from the weld area and the backside of the weld.
2. Regulators and Flow Meters: The panel is equipped with regulators and flow meters to control the pressure and flow rate of the purge gas. Precise control of gas flow is crucial to ensure adequate protection of the weld pool without causing turbulence that could introduce contaminants or interfere with the welding process.
3. Valves: Valves control the delivery of the purge gas to various zones, such as the welding torch for shielding the weld pool and the backside of the weld to prevent oxidation. These valves may be manually or automatically operated, depending on the system’s sophistication.
4. Gas Lines and Fittings: High-quality gas lines and fittings are used to transport the purge gas from the panel to the welding zone. These components are designed to be leak-proof to prevent the ingress of air and to ensure consistent gas flow.
5. Monitoring and Alarm Systems: Advanced purge gas panels may include sensors and alarm systems to monitor gas flow, pressure, and purity. These systems provide real-time feedback and can alert the operator to any issues that could compromise weld quality, such as low gas flow or leaks.
6. Purge Chambers or Enclosures (if applicable): For certain applications, the welding area may be enclosed in a chamber or bag that is then filled with purge gas to ensure a completely inert atmosphere.

Importance:

The use of a purge gas panel in orbital welding is critical for several reasons:

• Preventing Oxidation: The inert gas environment prevents the oxidation of the weld pool and the heat-affected zone, which is particularly important for materials that are prone to oxidation at high temperatures.
• Improving Weld Quality: A clean, inert atmosphere contributes to the formation of smooth, defect-free welds with optimal mechanical properties.
• Enhancing Purity: In industries such as semiconductor manufacturing, pharmaceuticals, and food processing, maintaining the purity of the weld is essential to prevent contamination of the products that will pass through the tubing or piping.
• Compliance with Standards: Many industries have strict standards and specifications for welding, which often include requirements for gas purity and welding atmosphere. The purge gas panel helps ensure compliance with these standards.

Overall, the purge gas panel is an essential component of the orbital welding system, ensuring that the welding environment is controlled and optimized for producing high-quality, consistent, and contamination-free welds.

Orbital welding is a specialized technique used primarily for the welding of pipes and tubes with a high degree of precision and consistency. This automated process involves a welding head that rotates, or orbits, around a stationary workpiece, creating uniform, high-quality welds. The process is highly controlled and programmable, making it ideal for applications in industries where weld quality is critical, such as in the semiconductor, pharmaceutical, aerospace, and food and beverage sectors.

Key Techniques in Orbital Welding:

1. Preparation: Proper preparation of the tube or pipe ends is critical. This includes precise cutting, facing, and cleaning to ensure the ends are square, smooth, and free of contaminants. The alignment of the tubing is also crucial to ensure a uniform weld.
2. Fixturing: The workpieces are clamped into position using specialized fixtures designed to hold them securely and maintain alignment during the welding process. This is essential for achieving consistent welds.
3. Purge Gas Setup: Before welding begins, the interior of the pipes or tubes is often purged with an inert gas, such as argon, to displace oxygen and prevent oxidation of the weld pool and the heat-affected zone. The use of a purge gas panel allows for precise control of the gas flow and pressure.
4. Program Selection and Parameter Setting: Orbital welding machines are equipped with programmable logic controllers (PLCs) that allow the operator to select from pre-programmed weld schedules or to input custom parameters. These parameters include welding current, arc voltage, travel speed, heat input, and gas flow rates.
5. Welding Process: The welding head, equipped with a tungsten electrode (in the case of TIG welding), is positioned around the pipe. Once activated, the head rotates around the pipe, creating an arc that melts the base material and any filler material to form the weld. The process is shielded by an inert gas to protect the weld pool from atmospheric contamination.
6. Monitoring and Quality Control: Many orbital welding systems are equipped with sensors and cameras that allow for real-time monitoring of the weld process. This enables immediate adjustments and quality control during the welding operation.
7. Cooling: Depending on the welding parameters and the materials being welded, a cooling system may be used to control the temperature of the welding head and the workpiece, preventing overheating and ensuring the integrity of the weld.

Advantages of Orbital Welding:

• Consistency and Reproducibility: The automated nature of orbital welding ensures that each weld is performed with the same parameters, leading to high consistency and repeatability.
• High Quality: The precision control over welding parameters results in high-quality welds with excellent mechanical properties and minimal defects.
• Efficiency: Orbital welding can be faster than manual welding, especially for repetitive tasks or in difficult-to-access areas.
• Reduced Operator Error: The automation of the welding process minimizes the chances of human error, which can be a significant factor in manual welding.
• Versatility: Orbital welding systems can be adapted for a wide range of tube and pipe diameters and materials.

Orbital welding requires specialized equipment and skilled operators who understand how to program and adjust the machine’s settings for different welding tasks. Despite the initial investment in equipment and training, the benefits of high-quality, consistent welds make it a preferred method in many high-tech and critical-application industries.

In orbital welding, the finishing of a welding joint involves several steps to ensure the weld is of high quality, meets the required specifications, and has a smooth and clean appearance. The process is highly automated, and the finishing quality is largely determined by the precision of the welding parameters and techniques used during the welding process.

Here’s how welding joints are typically finished in orbital welding:

1. Welding Process Execution:

• The orbital welding process itself is designed to produce a clean and smooth weld bead. High-quality orbital welding systems use precise control over welding parameters such as heat input, travel speed, and arc stability to create uniform welds with minimal spatter and defects.

2. Visual Inspection:

• After welding, the first step in finishing is a visual inspection to ensure the weld bead is uniform and free from visible defects such as cracks, undercuts, or porosity.

3. Non-Destructive Testing (NDT):

• Depending on the application’s criticality, non-destructive testing methods such as radiographic (X-ray) testing, ultrasonic testing, or dye penetrant inspection may be employed to detect any subsurface defects or inconsistencies within the weld.

4. Post-Weld Cleaning:

• Any discoloration or oxidation (often seen as a rainbow-like effect) around the weld area, particularly in stainless steel and other corrosion-resistant materials, is cleaned to restore the material’s corrosion resistance. Cleaning can be done using chemical passivation agents, mechanical polishing, or a combination of both, depending on the requirements.

5. Interpass Cleaning (if applicable):

• For multi-pass welds, where more than one layer of weld metal is deposited, interpass cleaning is performed between passes to remove any oxides or contaminants, ensuring a clean surface for subsequent weld layers.

6. Dressing and Grinding (if necessary):

• Although orbital welds are typically smooth and may not require dressing, any excess material or irregularities at the weld toe can be ground or polished to achieve the desired finish and contour. However, this is done sparingly to avoid reducing the weld’s integrity.

7. Final Inspection and Testing:

• A final inspection is conducted to ensure the weld meets all specified criteria, including dimensional tolerances and surface finish. Additional tests, such as pressure tests or leak tests, may be performed as required by the application standards.

8. Documentation:

• Comprehensive documentation of the welding parameters, inspection results, and any testing performed is maintained for quality assurance and traceability.

The aim in finishing a weld joint in orbital welding is to ensure that the weld is not only structurally sound

Inspecting a welding joint is a critical process to ensure the integrity, strength, and compliance of the weld with relevant standards and specifications. Various inspection methods, both non-destructive and destructive, can be employed depending on the requirements of the project and the nature of the welded materials. Here’s a general guide on how to inspect a welding joint:

Visual Inspection

1. Surface Examination:
   • Start with a visual inspection of the weld surface for any visible signs of defects such as cracks, porosity, undercutting, incomplete fusion, or spatter. Good lighting and sometimes magnification tools are essential for this step.
2. Weld Profile:
   • Check the weld profile for proper alignment, size, and contour. Ensure the weld has been properly shaped and meets the dimensional requirements specified in the welding procedure.
3. Weld Toe and Throat:
   • Inspect the transition from the weld metal to the base metal. The weld toe should be smooth and uniform, without any sharp notches that can be stress concentrators.

Non-Destructive Testing (NDT)

1. Liquid Penetrant Testing (LPT):
   • Suitable for detecting surface-breaking defects on non-porous materials. The surface is coated with a visible or fluorescent dye, which is drawn into surface-breaking defects by capillary action. After a specified dwell time, the surface is cleaned, and a developer is applied to draw out the dye from any defects, making them visible.
2. Magnetic Particle Testing (MPT):
   • Used for ferromagnetic materials to detect surface and slightly subsurface defects. The area is magnetized, and ferrous particles are applied. The particles accumulate at discontinuities, indicating the presence of defects.
3. Ultrasonic Testing (UT):
   • High-frequency sound waves are introduced into the material, and reflections from defects or discontinuities are analyzed. UT can detect both surface and subsurface defects and is useful for assessing the depth of defects.
4. Radiographic Testing (RT):
   • Uses X-rays or gamma rays to produce a radiograph of the weld, showing internal discontinuities. RT is effective for detecting porosity, inclusions, cracks, and voids inside the weld.
5. Eddy Current Testing:
   • Utilizes electromagnetic induction to detect surface and near-surface defects. It’s particularly useful for conducting inspections on coated surfaces without needing to remove the coating.

Destructive Testing

1. Tensile Testing:
   • A sample from the welded joint is pulled apart to determine the tensile strength of the weld. It helps in assessing whether the weld meets the required strength specifications.
2. Bend Tests:
   • The welded sample is bent to a specific angle to evaluate its ductility and soundness. Cracks or breaks on the tension side of the bend indicate weld defects.
3. Macroetching:
   • A cross-section of the weld is polished and etched with acid to reveal the weld’s internal structure. This test is useful for assessing weld penetration, fusion, and the presence of internal defects.

Final Evaluation

• Compare the findings from the inspections and tests against the acceptance criteria defined in the welding procedure specification (WPS) and relevant standards (e.g., ASME, AWS, ISO).
• Document the inspection results thoroughly, including descriptions and locations of any defects found. This documentation is crucial for quality control, traceability, and future reference.

It’s important to select the appropriate inspection methods based on the weld’s intended use, the criticality of the weld, and the types of materials welded. Additionally, inspections should be carried out by certified inspectors or professionals trained in the specific testing

Orbital welding is a highly specialized and automated welding process that finds application across various industries where precision, repeatability, and high-quality welds are essential. Some of the key applications of orbital welding include:

Aerospace Industry

• Fuel and Hydraulic Lines: Ensures leak-proof connections in critical systems.
• Engine Components: Provides high-integrity welds capable of withstanding extreme temperatures and pressures.

Semiconductor Industry

• Gas and Chemical Delivery Systems: Ensures ultra-high purity connections to prevent contamination in the manufacturing process of semiconductors.
• Process Piping: Used in the construction of cleanrooms and controlled environments where contamination must be minimized.

Pharmaceutical and Biotechnology Industries

• Process Piping Systems: Ensures sterile connections for the transportation of liquids and gases, critical in the manufacturing of pharmaceuticals and biotechnological products.
• Water for Injection (WFI) Systems: Requires high-purity welds to prevent contamination.

Food and Beverage Industry

• Process Lines: Ensures sanitary welds for pipelines that transport food and beverage products, maintaining hygiene standards.
• Packaging Equipment: Provides reliable welds in machinery used for packaging food and beverages, ensuring product integrity.

Nuclear Industry

• Cooling Systems: Delivers high-quality welds required for the safety and reliability of nuclear reactor cooling systems.
• Fuel Rod Fabrication: Ensures precise and consistent welds for the assembly of nuclear fuel rods.

Chemical Processing Industry

• Corrosive Fluid Handling Systems: Provides corrosion-resistant welds for pipes and containers used in the handling and storage of aggressive chemicals.
• Pressure Vessels and Reactors: Ensures the integrity of welds on vessels and reactors that operate under high pressure and temperature conditions.

Oil and Gas Industry

• Offshore Piping Systems: Delivers durable and reliable welds for pipelines and structures in corrosive marine environments.
• Downhole Instrumentation: Ensures high-quality connections for the reliable operation of equipment used in drilling and exploration.

Power Generation Industry

• Boiler Tubing: Provides consistent and strong welds required for the construction and maintenance of boilers.
• Heat Exchanger Tubing: Ensures the efficiency and reliability of heat exchangers through high-quality welds.

Automotive Industry

• Fuel Systems: Ensures the integrity of fuel lines and systems critical for vehicle safety.
• Exhaust Systems: Provides durable welds able to withstand high temperatures and corrosive gases.

Orbital welding’s ability to produce consistent, high-quality welds in difficult-to-access areas or where manual welding might not be feasible makes it an invaluable process in industries where weld integrity, precision, and reliability are paramount.

Orbital welding systems are produced by a range of manufacturers who specialize in welding equipment and technologies. These companies offer a variety of orbital welding products, including power sources, welding heads, and complete automated systems tailored for specific industry needs. Some of the prominent manufacturers in the orbital welding industry include:

1. Swagelok:
   • Known for their high-quality fluid system products, Swagelok also offers a range of orbital welding equipment, including power supplies, welding heads, and accessories designed for precision and reliability in critical applications.

1. AMI (Arc Machines, Inc.):
   • AMI is a leading manufacturer of orbital welding equipment, known for their advanced welding systems used in a variety of industries, including aerospace, semiconductor, pharmaceutical, and more.
2. Magnatech:
   • Specializes in the design and manufacture of orbital welding equipment for tube and pipe welding, with a focus on user-friendly interfaces and high-quality welding results.
3. Polysoude:
   • Polysoude is renowned for their expertise in TIG and plasma welding technologies, offering a wide range of orbital welding equipment and automated welding solutions for demanding industrial applications.
4. Fronius:
   • Fronius is a globally recognized company that provides innovative welding technologies, including orbital welding systems that are known for their performance and reliability.
5. ESAB:
   • A global leader in welding and cutting equipment and consumables, ESAB offers orbital welding solutions that cater to various industry requirements.
6. Lincoln Electric:
   • Known for their comprehensive range of welding and cutting products, Lincoln Electric also offers orbital welding systems designed for high-quality welds in challenging environments.
7. Techsouth Inc.:
   • Techsouth Inc. is known for producing portable orbital welding equipment, including power sources and welding heads, suitable for a variety of on-site applications.

When selecting an orbital welding system, it’s important to consider the specific requirements of your application, including the materials to be welded, the precision needed, the environment in which the welding will take place, and any industry-specific standards that must be met. Each manufacturer offers unique features and benefits, so reviewing the specifications, support, and service options from multiple suppliers can help in choosing the best system for your needs.