Orbital welding puts a mechanized head around a fixed tube joint and lets the torch do the traveling. Every weld identical, every parameter recorded — the process behind semiconductor, pharmaceutical, and nuclear piping.
Orbital welding is TIG — or occasionally plasma — mechanized onto a ring that clamps around the pipe or tube. The head rotates the electrode around the stationary joint while the power source runs a programmed sequence: pre-flow, upslope, weld current, downslope, post-flow.
Because the arc is machine-controlled and the parameters are recorded, every weld is essentially identical — and every weld is documented. That traceability is why ultrapure and safety-critical lines are orbital by specification. The operator's job becomes preparation: square cuts, tight fit-up, clean metal, and a proper purge.
Stainless tube, autogenous orbital TIG — the daily bread.
| Tube OD | Wall | Amps | RPM | Purge cfh |
|---|---|---|---|---|
| 1/4 in | 0.035 in | 35–55 | 2–3 | 3–5 |
| 1/2 in | 0.049 in | 55–75 | 1.5–2.5 | 5–8 |
| 1 in | 0.065 in | 75–100 | 1–2 | 8–12 |
| 2 in | 0.083 in | 100–130 | 0.8–1.2 | 12–18 |
| 3 in | 0.120 in | 130–160 | 0.6–1 | 18–25 |
| Property | Manual TIG | Orbital |
|---|---|---|
| Consistency | Operator-dependent | Programmed, identical |
| Documentation | Manual | Automatic data log |
| Speed per weld | Slow | Minutes, repeatable |
| Skill needed | Years of hand practice | Procedure discipline |
| Access | Tight spaces hard | Head fits, you're fine |
Orbital power supply with programmed sequences, gas control, and data logging.
Browse power sources →Clamped heads for small bore, open-frame heads for pipe — one per tube size range.
Browse torches →Purge dams, argon regulators, and an oxygen meter — the root quality control.
Square, burr-free cuts are non-negotiable — cutting and facing tools do it right.
Weld data transfer, barcode labelers, and borescopes for root inspection.
Carousels and tube trailers move work to the weld station for production runs.
Browse automation →The whole point of orbital is that position doesn't matter — the head orbits the joint wherever it is.
The tube stays put, the head orbits — field welding in place, all positions at once.
The tube rotates under a fixed torch — shop bench welding at production speed.
Heads fit where hands can't — behind cabinets and inside skids.
The program handles gravity — amperage profiles are tuned per orientation.
Orbital technique lives in the program and the setup — six moves that make the difference.
Filler-free full-penetration welds on thin-wall tube — clean, fast, and spec-friendly.
Programs pulse or step current around the orbit — hotter at the bottom, cooler at the top.
Adds filler for thick walls and gap bridging — wire speed synced to the program.
The head overlaps the start point and downslopes — a clean closure is the mark of good programming.
Thick-wall pipe gets root plus fill passes, each with its own program segment.
Plasma heads for heavy-wall pipe — deeper penetration, thicker single-pass welds.
The machine is consistent — when orbital welds go wrong, it's almost always preparation or purge.
Appearance
Pits in the bead or root — gas trapped in the frozen weld.
Causes
Contaminated tube ends, purge oxygen too high, or a bad gas seal.
Prevention
Degrease, meter the purge, and tape the joint gas-tight.
Appearance
Cold line along the root — the two tube ends never fully melted together.
Causes
Gap too small, current too low, or rotation too fast.
Prevention
Check gap and program — the fix is in the procedure.
Appearance
A groove where the head closes the orbit — the overlap zone.
Causes
Downslope too fast or overlap current too high.
Prevention
Tune the closure segment — slope and overlap current.
Appearance
Bright flecks in the weld — tungsten touched the puddle.
Causes
Stick-out too long or the tungsten set too low into the joint.
Prevention
Set stick-out against the tube radius and re-dress the point.
Appearance
Bead running off the seam — the weld hugs one tube side.
Causes
Joint not centered in the head or tube OD mismatch.
Prevention
Center the joint, check alignment with the head gauge.
Appearance
Grey or rainbow root — the purge failed somewhere.
Causes
Oxygen above the limit, dams leaking, or flow too low.
Prevention
Meter oxygen, seat the dams, verify flow before arc start.
Appearance
The root pushes through the bore — a proud internal bead.
Causes
Gap too wide or purge pressure pushing the puddle inward.
Prevention
Tighten the gap and drop purge pressure a touch.
Appearance
Crack at the weld closure — the crater froze shrunken.
Causes
Downslope too steep or no crater-fill segment.
Prevention
Program a gentle slope-out with a filler step.
The documents behind orbital quality — most orbital work is done to one of these.
| Standard | Covers |
|---|---|
| ASME BPE | Bioprocessing equipment — the sanitary orbital rulebook |
| AWS D18.1 | Welding of austenitic stainless steel tube in sanitary applications |
| ASME B31.3 | Process piping — orbital allowed for code lines |
| ASME Section VIII | Pressure vessels — tube attachments and heat exchangers |
| ASME Section IX | Welding qualification for pressure equipment |
| ISO 14732 | Qualification of welding operators — mechanized processes |
| EN 13480 | European industrial piping rules |
| ASME B31.1 | Power piping — boiler and plant tube welds |
All-in-one machine settings helper for a fast orbital starting point.
Amps and orbit speed — the number that controls penetration and heat.
Set purge flow and read the gas usage your orbital cell needs.
Match wire to base metal for cold-wire and heavy-wall passes.
What amps and orbit speed fit thin tube vs heavy-wall pipe.
See head setup, purge checks, and overlap control on real tube.
Watch the setup sections — head centering, purge metering, and program loading — on real metal.
Watch VideosA shop-floor cheat sheet with the parameter table, purge limits, and gas quick reference.
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