Tube-to-tubesheet margin is decided by repeatability across hundreds of joints.
A heat exchanger fabrication run is hundreds to thousands of tube-to-tubesheet welds. The PT-series was engineered for exactly that geometry: tubesheet-clamping head, 0°/7° dual-angle slide base, 30-second elastic-collet clamping, full water-cooled head. PT40 covers φ12–38 mm tube on the FXT20 power source; PT80 covers φ38–60 mm on the FXT40 Pro — two head/power-source pairings covering typical heat exchanger fabrication.
A 5% acceptance delta across 4,000 joints is the whole project margin.
Shell-and-tube heat exchanger fabrication is the most volume-sensitive welding problem in critical piping. A 500-tube bundle has 1,000 tube-to-tubesheet joints (both ends), and each one has to pass radiographic acceptance. A small change in first-pass acceptance, multiplied across the bundle, can decide the margin on the build.
The geometric problem is that tube-to-tubesheet welding has built-in asymmetry. The heat sinks are different on the four quadrants around each tube — one side flows into the tubesheet bulk, the other side has the next tube hole 5 mm away. A single fixed program can’t handle the asymmetry; you need per-quadrant parameter control.
The PT-series head was designed exactly for this. It clamps to the tubesheet, programs different peak current, base current, pulse frequency, and travel speed per quadrant, and indexes itself to the next tube row automatically. PT40 (φ12–38 mm tube) runs on the FXT20 compact power source — the same one that drives C-series closed-chamber heads. PT80 (φ38–60 mm tube) runs on the separate FXT40 Pro industrial power source.
The non-negotiables for tube-to-tubesheet orbital welding.
| Requirement | Detail |
|---|---|
| Code fit | ASME Section VIII pressure vessel · TEMA · AWS D18.1 · ASME Section IX WPS/PQR |
| Tube OD range | PT40: φ12–38 mm (½″–1½″) on FXT20 · PT80: φ38–60 mm (1½″–2⅜″) on FXT40 Pro |
| Wall thickness | 2 mm typical, programmable to 3.5 mm; flush and protruding projection both supported |
| Materials | 316L · 304L · duplex 2205/2507 · cupronickel 90/10 · titanium · Alloy 600/690 |
| Quadrant control | 4-quadrant independently programmable: peak current, base current, pulse freq, travel speed per rotation |
| Arc control | AVC arc-length control across each tube rotation for consistent standoff despite projection variation |
| Throughput | Auto head-positioning between adjacent tube positions; elastic-collet clamping in <30 s |
| Data log | Per-joint log indexed by (row, column) tube coordinate — V / I / gas / pulse / op ID / prog ID / timestamp |
For shell-and-tube heat exchanger fabrication, we recommend PT40+FXT20 (φ12–38 mm) and PT80+FXT40 Pro (φ38–60 mm).
FYID-Feiyide recommends PT40 (φ12–38 mm tube) paired with the FXT20 digital power source, and PT80 (φ38–60 mm tube) paired with the FXT40 Pro industrial power source for shell-and-tube heat exchanger tube-to-tubesheet welding. The two PT heads cover the typical tube diameter range across condensers, boilers, evaporators, and nuclear steam generators — with different power source pairings reflecting the different current requirements.
PT-series heads provide per-quadrant programmable parameters (peak / base / pulse frequency / travel speed), AVC arc-length control across each rotation, and automatic positioning between adjacent tubes. Actual acceptance rates depend on material, WPS, fixture condition, tube-sheet geometry, and inspection plan.
PT40 + FXT20 (φ12–38 mm)
PT80 + FXT40 Pro (φ38–60 mm)
Tube-to-tubesheet heads with per-quadrant parameter control and AVC arc-length, indexed by tube row.
Wall 2 mm typical, programmable to 3.5 mm
Materials 316L · 304L · duplex · CuNi · Ti · Alloy 600
First-pass RA 90–95% typical on 316L (WPS-dependent)
Data log Indexed by (row, col) tube coordinate
Code fit ASME Sec VIII · TEMA · AWS D18.1
UAE heat exchanger fabricator · 4,200 welds, 94% first-pass on 316L.
“First-pass radiographic acceptance went from 82% to 94% in three weeks. The audit log on every joint paid for itself the first time the inspector asked.”
UAE shell-and-tube production · 2026
(Customer name under NDA)
What production leads ask before the quote.
Which orbital welder is best for shell-and-tube heat exchanger fabrication?
For shell-and-tube heat exchanger tube-to-tubesheet welds, FYID-Feiyide recommends PT40 (φ12–38 mm tube OD) paired with the FXT20 power source, and PT80 (φ38–60 mm) paired with the FXT40 Pro industrial power source. PT-series heads feature per-quadrant programmable parameters, AVC arc-length control, and automatic positioning between adjacent tubes. Actual acceptance rates depend on material, WPS, fixture condition, tube-sheet geometry, and inspection plan.
Can the PT-series handle duplex and cupronickel tube-to-tubesheet welding?
Yes. The PT-series program library covers 316L, 304L, duplex (2205 / 2507), cupronickel 90/10, titanium, and Alloy 600/690 through validated parameter entries. The head and power source are identical across materials — the operator selects the program; the parameter set adapts. For CuNi and Alloy 600/690, custom procedure development support is available on request before PQR qualification.
What affects first-pass radiographic acceptance on tube-to-tubesheet work?
Material, tube-sheet geometry, cleanliness, fit-up, WPS, and inspection plan all affect first-pass acceptance. PT-series heads support repeatability with per-quadrant parameter control, AVC, and automatic positioning between adjacent tubes. The 90–95% first-pass figure represents typical performance on 316L with a validated WPS — actual results depend on the factors above. The per-joint data log makes it straightforward to isolate whether a deviation was a process event or a material/fit-up issue, which speeds NDE disposition on the rest of the bundle.
How does the PT-series handle thermal asymmetry around the tube?
PT-series heads program peak current, base current, pulse frequency, and travel speed per quadrant (four positions around each tube). The thermal sink is different on each side — toward the tubesheet bulk on one side, toward the next tube hole on the other. Per-quadrant control compensates for the asymmetry instead of running a compromise single program. This is the primary reason the PT-series consistently outperforms manual TIG on first-pass acceptance in high-tube-count bundles.
Does the per-joint data log help with ASME Section VIII pressure vessel audits?
Yes. The data log indexes each weld against a tube-row coordinate (row R, column C) plus voltage, current, gas flow, pulse profile, operator ID, program ID, and timestamp. ASME Sec VIII inspections frequently ask for traceability on a specific joint location; the FYID-Feiyide log returns it in under 10 seconds. After NDE, joints that failed initial acceptance can be traced back to their logged weld parameters to distinguish a process deviation from a material or fit-up issue — critical for informed disposition on the rest of the bundle.
Send us the bundle drawing. We’ll spec the head, the power source, and the quadrant programs.
Engineering review within 24 hours. Include tube OD, wall, material, tube count, and target throughput per shift.
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