Orbital Welding: The Complete Process Guide

This guide covers how orbital welding works, when to use it, how it compares to manual TIG welding, and which industries rely on it. If you’re evaluating orbital welding equipment for sale or hire, this is the right place to start.

What Is Orbital Welding and How Does It Work?

Orbital welding uses the Gas Tungsten Arc Welding (GTAW/TIG) process in most applications, with the key difference being automation. The welding head clamps around the tube joint and rotates mechanically, guided by pre-programmed welding parameters stored in a computer-controlled power source.

The power source does several things simultaneously: it controls arc current, travel speed, pulse timing, and gas switching, and it drives the rotation of the welding head. Because every parameter is set before welding begins and applied identically every time, the process produces a repeatable weld on every joint. Regardless of the operator's skill level for that particular pass.

The Main Components of a TIG Orbital Welding System

A complete orbital welding system typically consists of:

1. Weld head: clamps around the pipe and houses the rotating tungsten electrode; closed heads are used for small diameter tubes, open heads for larger diameters or where filler wire is required
2. Power source/controller: stores welding programmes, controls all parameters, and drives the weld head
3. Shielding gas supply: typically pure argon at 99.995% purity (grade 4.5) for most materials
4. Weld purging system: protects the internal bore of the tube from oxidation during welding
5. Tube preparation tooling: orbital pipe saws or facing tools to ensure square, clean tube ends

Orbital TIG vs Orbital MIG Welding

Most orbital welding uses the TIG (GTAW) process, which is the standard for tube and pipe sizes under 168mm OD and for all high-purity applications. Orbital MIG (GMAW) is used on larger-diameter pipework, where its higher deposition rates make multi-pass welds faster to complete; pipeline construction is the most common example. On very small diameter tubes (under 38mm OD), autogenous orbital TIG welding is common: no filler metal is added, so precise joint preparation and fit-up are essential.

Types of Orbital Welding Joints

Orbital welding is used across the main tube and pipe joint configurations: tube-to-tube and pipe-to-pipe butt welds are the most common, while tube-to-tubesheet welding (joining tubes into the drilled plate of a heat exchanger, condenser, or boiler) is a specialised application with its own dedicated weld head type.

What Shielding Gas Does Orbital Welding Use?

The correct shielding gas choice depends on the material being welded:

• Pure argon (99.995% / grade 4.5) is the standard for most stainless steel, carbon steel, and general alloy tube welding.

• Higher purity argon (99.998% / grade 4.8) is required for reactive metals such as titanium, tantalum, and zirconium — any contamination risk is unacceptable with these materials.

• Argon-hydrogen mixtures (2–5% hydrogen) can increase heat input by 10–20%, improving penetration and welding speed on austenitic stainless steels. However, hydrogen is strictly prohibited with aluminium, titanium, and mild or carbon steel, where it causes porosity and cold cracking.

• Argon-helium mixtures are used where greater energy input is needed without the risks of hydrogen. Helium increases arc voltage and widens the arc column for deeper penetration, and is suitable for aluminium, titanium, and high-conductivity alloys. Because helium is lighter than argon, flow rates need to be two to three times higher to achieve equivalent shielding coverage.

• Argon-helium-nitrogen mixtures are specified for duplex and super duplex stainless steels.

Weld Purging

Weld purging (flooding the tube bore with an inert gas before and during welding) is essential for most orbital TIG applications. Without purging, oxygen and nitrogen on the underside of the weld cause oxidation, porosity, and loss of corrosion resistance. Professional inflatable purge plugs are the correct approach; cardboard discs and improvised solutions are neither reliable nor practical on production work.

How to Prepare Joints for Orbital Welding

Because autogenous orbital TIG welding adds no filler metal in most small-diameter applications, the weld quality depends entirely on the quality of the joint preparation. The tube ends must be square, clean, and perfectly matched. Any gap, burr, or contamination at the joint interface will produce a defective weld that no amount of parameter adjustment can correct.

Orbital pipe saws and facing machines are designed specifically for this task; they produce a square, burr-free face with the surface finish and dimensional accuracy that orbital welding demands. The welding head is then clamped around the prepared joint, the purge is set up if required, and the pre-saved welding programme is selected and run.

For new jobs, weld trials are essential to establish and prove welding parameters before production begins. For repeat jobs, the saved programme reproduces the same weld every time.

What Are the Advantages of Orbital Welding?

Orbital welding was developed to solve specific problems that manual welding cannot reliably address at scale: consistency on small diameter tubes, quality in restricted-access positions, and repeatability across high-volume production runs.

The key advantages over manual TIG welding are:

• Repeatability: every weld is produced to the same parameters; human variation is removed from the process
• Access: the weld head can reach joints that a manual welder physically cannot, including confined spaces and overhead positions
• Weld quality: smoother bead profile, better fusion, greater corrosion resistance, and improved mechanical integrity compared to hand-welded equivalents
• Purity: the controlled arc and enclosed environment produce virtually contamination-free welds, essential for sanitary and high-purity applications
• Speed on high-volume work: once a programme is established, orbital welding is significantly faster than manual TIG on production runs
• Reduced operator dependency: operators don’t need years of manual TIG skill to produce high-quality welds; the skill moves into setup, programming, and quality control

Orbital welding does have limitations: it is not suited to every TIG application, it requires capital investment in equipment, and it needs proper maintenance (tungsten electrode condition, cooling unit cleanliness, cable checks, and annual power source calibration) to deliver consistent results. But for repetitive pipe and tube work in quality-critical environments, it is the most reliable process available.

Orbital Welding vs Manual Welding: Which Is Right for Your Application?

Orbital welding is not a replacement for all manual welding; it is the right choice for specific situations. The question to ask is whether your application involves repetitive tube or pipe joints where consistent quality is non-negotiable.

Choose orbital welding when:

• You’re welding high volumes of tube joints to the same specification
• Weld quality is safety-critical, and failure would be catastrophic or costly (pharmaceutical, aerospace, nuclear, food processing)
• Access is restricted, and a manual welder cannot achieve a complete, consistent weld
• Corrosion resistance, surface purity, or weld integrity must be maintained without variation
• Documentation and traceability of welding parameters are required

Manual TIG welding may be more appropriate when:

• Weld volumes are low, and the capital investment in orbital equipment isn’t justified
• Joint configurations are irregular or non-circular, where a rotating head cannot be applied
• You’re doing welding repair work or one-off fabrications rather than production runs

The learning curve comparison is also worth noting: mastering manual TIG welding to a high standard takes years. An operator can be trained to set up, programme, and run an orbital welding system in a fraction of that time. Though understanding the process well enough to troubleshoot and develop new programmes still requires solid welding knowledge.

Orbital welding is a mechanised process, but it is not a fully autonomous one. Skilled operators are always required; they set up the equipment, qualify welding procedures, check joint preparation, and monitor weld quality. The machine removes variability in manual welding; the operator brings process understanding.

For more information on welding automation, read our complete guide.

Which Industries Use Orbital Welding?

Orbital welding is relied upon wherever tube and pipe joints must meet the highest quality standards, often under regulatory scrutiny. The following industries are its primary users.

Food, Dairy, and Beverage

Stainless steel pipework in food, dairy, and beverage production must have smooth, fully penetrated welds with no crevices where bacteria can accumulate. Regulatory frameworks governing sanitary welding (including EHEDG and 3-A Sanitary Standards) mandate weld surface quality that orbital TIG reliably achieves. Overheating stainless steel during welding causes carbon precipitation and loss of corrosion resistance, and the controlled heat input of orbital welding prevents this.

Pharmaceutical and Biotechnology

Pharmaceutical manufacturing environments are among the most regulated in the world. Systems producing injectable medicines, vaccines, and high-purity fluids, including WFI (Water for Injection) and CIP (Clean in Place) systems, require tube welds with zero crevices, full-bore penetration, and no contamination risk. Orbital TIG is the industry standard for these applications; hand welding these systems to the required standard is, in most cases, not feasible.

Semiconductor Manufacturing

Semiconductor fabrication plants rely on miles of stainless steel tubing to transport toxic and corrosive process gases. Weld purity requirements are among the most stringent of any industry; even microscopic contamination can destroy a chip production batch. Orbital TIG with enclosed weld heads has been the semiconductor industry standard since the early 1980s. Brands such as AMI, Magnatech, and Orbitalum are commonly specified in this sector.

Oil, Gas, and Petrochemical

Offshore platforms, subsea pipelines, and petrochemical plant pipework all involve high-consequence welds where failure causes environmental and capital damage. The oil and gas industry uses orbital welding for both fine-bore instrument tubing and large-diameter pipeline construction. The AMI Model 15, for example, is a pipeline-grade weld head designed for outdoor use in demanding conditions. The consistency of orbital welding improves weld inspection pass rates, which directly reduces pipeline construction time.

Aerospace

The aerospace industry was the first to adopt orbital welding, developed initially for aerospace hydraulic and fuel lines. Aircraft can contain thousands of critical fuel and hydraulic tubes exposed to cyclic loading and thermal stress. Any weld defect in these lines represents a safety hazard. Computer-controlled orbital welding provides the heat input precision and process control that aerospace welding specifications demand.

Power Generation

Boiler tube welding in fossil fuel and nuclear power plants requires orbital welding systems to meet stringent standards in confined spaces. Heat exchangers, superheaters, reheaters, and economisers all involve large numbers of repetitive tube joints in tight configurations (including tube-to-tube sheet joints), exactly the application for which orbital welding was built.

Shipbuilding

Modern ships contain extensive piping systems for cooling, fuel, steam, fire suppression, and ballast. These systems require quality welding in cramped spaces, often in challenging positions. Orbital welding addresses both the access problem and the quality requirement, and is used to meet international naval and commercial shipbuilding codes. Some vessels additionally require welding of exotic alloys, including titanium and high-nickel materials, all within the capability of orbital TIG.

Orbital Welding Equipment: What to Look For

A complete orbital welding system consists of the power source and one or more weld heads. The choice of weld head type depends primarily on the tube or pipe diameter and whether filler wire is required:

Closed weld heads are fully enclosed around the tube, providing maximum shielding gas coverage. They are used for small to medium diameter tubes (typically up to around 170mm OD) and for autogenous welding. They are the standard choice for pharmaceutical, food, semiconductor, and similar sanitary applications.

Open weld heads are used for larger diameters and for applications requiring filler wire addition. They provide access for arc viewing and adjustment during welding.

Pipeline weld heads (such as the AMI Model 15) are designed for larger diameter pipe, often in field conditions, and incorporate dual wire feed capability for multi-pass welding.

Tube-to-tubesheet weld heads are designed specifically for welding tube ends into tubesheets on heat exchangers and similar equipment, centring on the tube bore and rotating the electrode around the joint face.

Westermans stocks new and used orbital welding equipment from leading brands, including AMI, Polysoude, Magnatech, Orbitalum, Axxair, and Swagelok. Equipment is available for outright purchase or hire, with hire particularly suited to project-based work where capital investment is hard to justify. Annual calibration of the power source is recommended to maintain the accuracy that orbital welding demands.

View current orbital welding equipment for sale and hire →

Frequently Asked Questions: Orbital Welding

What is orbital welding?

Orbital welding is an automated arc welding process in which the welding torch rotates 360° around a stationary pipe or tube joint. The process is controlled by a pre-programmed power source that sets and maintains all welding parameters: current, travel speed, pulse timing, and gas flow throughout each weld. In most applications, it uses the TIG (GTAW) process, and it is primarily used for tube and pipe joining in industries where consistent, high-quality welds are essential.

What is the difference between orbital welding and manual TIG welding?

In manual TIG welding, a skilled operator controls the torch position, travel speed, and heat input by hand, producing results that vary with technique and fatigue. Orbital welding removes these variables: a weld head clamps to the joint and rotates mechanically to a fixed programme, producing the same weld every time. Orbital welding is faster on high-volume work, achieves better consistency and purity, and can reach joints that a manual welder cannot access. Manual TIG remains appropriate for low-volume, irregular, or repair work where orbital equipment cannot be set up.

Which industries use orbital welding?

The primary industries using orbital welding are food, dairy, and beverage; pharmaceutical and biotechnology; semiconductor manufacturing; oil, gas, and petrochemical; aerospace; power generation; and shipbuilding. What these sectors share is a need for tube and pipe welds that are repeatable, fully traceable, and free from defects that could cause contamination, leaks, or structural failure.

What are the main advantages of orbital welding for industrial pipe work?

For industrial pipe applications, the key advantages are: repeatable weld quality regardless of operator, access to joints in confined or overhead positions, higher weld purity suited to sanitary and corrosion-critical environments, faster throughput on high-volume production, and the ability to document and qualify welding procedures against specific parameters. For organisations running large numbers of identical joints, orbital welding typically reduces rework rates and improves weld inspection pass rates compared to manual alternatives.

What shielding gas is used in orbital welding?

Pure argon at 99.995% purity (grade 4.5) is the standard for most orbital TIG applications. Higher-purity argon (grade 4.8) is required for reactive metals such as titanium and zirconium. Argon-hydrogen mixtures can increase heat input on austenitic stainless steel but cannot be used with aluminium, titanium, or carbon steel. Argon-helium mixtures provide deeper penetration for high-conductivity materials. Duplex and super duplex steels require argon-helium-nitrogen blends.

Can orbital welding equipment be hired rather than purchased?

Yes. Westermans operates an orbital welding hire fleet, which is well-suited to project-based work, contract jobs, or situations where purchasing a full system isn’t justified by volume. Hire equipment covers both power sources and weld heads. View the orbital welding hire fleet here, or contact the team to discuss requirements for your specific tube diameter and material.

Westermans International has supplied new and used orbital welding equipment globally for over 50 years. The stock includes power sources, weld heads, and complete systems from AMI, Polysoude, Magnatech, Orbitalum, Axxair, and Swagelok, available for sale or hire with worldwide delivery. Browse orbital welding equipment →