FYID Automated Tube-to-Tubesheet Orbital Welding System | PT40/PT80 Heads with FXT20 Digital Power Supply

Automated Tube-to-Tubesheet Orbital TIG Welder for Boilers, Heat Exchangers, and Nuclear Equipment — Φ12 mm to Φ38 mm Tube OD, All-Position Autogenous GTAW

The FYID-Feiyide PT40 is a purpose-built automated orbital GTAW (TIG) welding head for tube-to-tubesheet seal welds — the circumferential butt-end joint connecting individual heat exchanger or boiler tubes to the tubesheet face. Paired with the FXT20 programmable power source (5 A – 200 A DC), the PT40 forms a complete tube-to-tubesheet automatic welding system covering tube outer diameters from Φ12 mm to Φ38 mm, in carbon steel, stainless steel, and titanium alloy, without filler wire.

The PT40 welding head weighs 3 kg and measures 300 × 150.5 × 143.5 mm — dimensioned specifically to extend into the tube box of a heat exchanger or boiler drum and reach interior tubesheet joints that are inaccessible to conventional tube-to-tubesheet welding equipment. The elastic collet clamping mechanism completes radial and axial dual positioning in three steps (insert, lever, lock) without manual support, reducing clamping time from the industry norm of 5 minutes to under 30 seconds per joint. A single operator can manage multiple PT40 heads simultaneously on large-tubesheet fabrication runs.

The DC servo motor drive provides stepless rotation speed from 0.6 rpm to 12 rpm with full closed-loop control — the same drive architecture used in the FXT20 Pro-C U-bend system — ensuring consistent rotation speed through flat, vertical, and overhead positions without the speed deviation that stepper-motor systems exhibit in overhead passes. The full water-cooled design (gear shaft, turntable, and tungsten electrode holder all water-cooled, flow ≥600 ml/min) sustains 100 A at 70% duty cycle for extended multi-head production runs without torch degradation.

For tube-to-tubesheet joints in larger tube diameters (Φ38 mm – Φ80 mm) or applications requiring filler wire or fillet weld geometry, contact FYID-Feiyide's applications engineering team for special welding head and modification kit options.

PT40 + FXT20 System Specifications — Welding Head and Power Source

PT40 Tube-to-Tubesheet Welding Head

FXT20 Power Source (paired with PT40)

Dual-angle slide base and gas nozzle configuration

The PT40 standard configuration includes a 0°/7° dual-angle slide base and Φ25 mm / Φ38 mm dual-specification gas nozzles. Switching between the 7° electrode angle (for Φ12 mm – Φ28 mm tube) and the 0° angle (for Φ25 mm – Φ38 mm tube) requires component replacement — no separate head is needed. This single-head multi-range design covers the full Φ12 mm – Φ38 mm diameter range that represents the mainstream tube size in economizer, superheater, shell-and-tube heat exchanger, and steam generator fabrication, reducing redundant equipment investment in shops that run mixed tube-size production.

Industry Applications for the PT40 Tube-to-Tubesheet Automated Welding System

Industrial Boiler Manufacturing — Economizer and Superheater Tube-to-Tubesheet Seal Welds

Power station and industrial boilers contain economizer and superheater sections where hundreds to thousands of carbon steel tubes are seal-welded to drum headers or tubesheets. These joints operate under continuous thermal cycling at temperatures of 300°C – 600°C and pressures of 5 MPa – 25 MPa, making the tube-to-tubesheet seal weld one of the highest-consequence joints in the boiler assembly. A single failed seal weld causes steam or water leakage into the flue gas path — a shutdown event that in large utility boilers costs operators hundreds of thousands of dollars per day in lost generation capacity.

Manual tube-to-tubesheet welding in boiler drums has two persistent quality problems. First, the drum interior geometry forces the welder into constrained positions for tubes in the lower and side tube rows, producing posture-dependent quality variation between the top-of-drum tubes (flat welding, easiest) and the side and bottom tubes (vertical and overhead, most difficult). Second, in large boiler drums with tube counts exceeding 500, weld quality naturally degrades across a shift as operator fatigue accumulates. The PT40's all-position DC servo rotation produces the same weld profile at every tube position regardless of the welder's access angle — the head is inserted and locked into each tube, the program runs automatically, and the operator repositions to the next tube.

The 30-second elastic collet clamping mechanism sustains production throughput on high-tube-count boiler drums. The 100 A / 70% duty cycle water-cooled design supports continuous multi-shift production without thermal degradation. Compatible materials: carbon steel (SA-210, SA-192), stainless steel (SA-213 TP304, TP316). Tube OD Φ12 mm – Φ38 mm. Relevant code: ASME Section I (Power Boilers), EN 12952.

Shell-and-Tube Heat Exchanger Fabrication — All-Position Tube-to-Tubesheet Seal Welding

Shell-and-tube heat exchangers in petrochemical, refinery, and chemical process service are fabricated to ASME Section VIII Div. 1, TEMA, or GB/T 151, all of which require tube-to-tubesheet joints to be either expanded, seal-welded, or both (strength-welded). For services where tubesheet joints must be leak-tight under process pressure — high-pressure hydrocarbon service, toxic fluid service, or high-differential-pressure designs — seal welding is mandatory. In a typical process heat exchanger with 200 to 600 tubes, the seal welding scope represents the single largest welding labor input in the fabrication sequence.

The PT40 reduces the labor variable in this scope to head positioning and program selection. Once the program for a given tube OD and material is stored in the FXT20's 200-group parameter library, every production weld in that specification is executed identically — current profile, rotation speed, pre-flow, post-flow — with no operator-to-operator or shift-to-shift variation. The FXT20's built-in printer generates a weld report for each joint, creating the per-tube weld record that supports ASME Section VIII Manufacturer's Data Report documentation and third-party inspection sign-off. For heat exchangers in lethal service (ASME Section VIII UW-2), where full radiographic inspection of all welds is mandatory, the PT40's weld consistency directly reduces radiographic rejection rates and re-weld scope.

Compatible tube OD: Φ12 mm – Φ38 mm. Materials: carbon steel, stainless steel (304, 316L), duplex stainless (2205), titanium alloy. Relevant standards: ASME Section VIII Div. 1, TEMA C/B/R, GB/T 151.

Nuclear Power Equipment — Steam Generator Tube-to-Tubesheet Precision Welding

Nuclear steam generators contain tens of thousands of thin-wall Alloy 600 or Alloy 690 tubes seal-welded to the primary-side tubesheet. These joints are among the most safety-critical welds in nuclear power plant construction: they form the boundary between primary coolant (radioactive) and secondary steam, and any through-wall defect is a radiological release pathway. Nuclear steam generator tube-to-tubesheet welding is qualified under ASME Section III (Nuclear Components) with WPS/PQR documentation, weld record traceability to tube heat number and tubesheet location, and 100% inspection by either liquid penetrant or eddy current.

The PT40's DC servo closed-loop drive and full water-cooled design were selected for nuclear applications because they eliminate the two primary sources of weld variability in this joint: rotation speed deviation across the full 360° (addressed by servo closed-loop) and torch degradation from thermal cycling across a high-count production run (addressed by full water cooling). The FXT20's per-weld data logging — current, rotation speed, arc voltage, zone index, timestamp — produces the weld parameter traceability record required by nuclear quality programs (10 CFR 50 Appendix B, ASME NQA-1). For nuclear auxiliary piping girth welds rather than tube-to-tubesheet joints, see the FXT40 Pro with K-series heads.

Compatible materials: Alloy 600, Alloy 690, 316L stainless steel, carbon steel. Tube OD Φ12 mm – Φ38 mm. Relevant standards: ASME Section III, ASME Section IX, NQA-1, 10 CFR 50 Appendix B.

Chemical and Petrochemical Reactor Equipment — Corrosion-Resistant Tube-to-Tubesheet Welding

Shell-and-tube condensers, reboilers, and reactor feed/effluent exchangers in chemical and petrochemical service often use corrosion-resistant tube materials — titanium Grade 2, duplex stainless steel 2205, or high-alloy stainless — to resist process-side corrosion from acids, chlorides, or hydrogen sulfide. These alloys are significantly more sensitive to heat input variation than carbon steel: titanium requires full inert gas coverage during welding (atmospheric oxygen contact above approximately 400°C produces embrittlement), and duplex stainless requires controlled heat input to maintain the austenite-ferrite phase balance that provides its corrosion resistance.

The PT40's programmable multi-segment current control allows the FXT20 to ramp current precisely through arc initiation, steady-state, and decay phases on each pass — maintaining heat input within the narrow process window for duplex stainless phase balance and providing the pre-flow and post-flow argon timing that titanium requires. For titanium tube-to-tubesheet joints, the argon shielding volume provided by the PT40 head covers the weld zone during the full cycle. The 3 kg head weight allows one operator to manage multiple heads on large-bundle condensers without the ergonomic fatigue that conventional 8 kg – 15 kg bore welding heads impose on operators working inside vessel shells.

Compatible materials: titanium Grade 2, duplex stainless 2205, 316L, 904L. Tube OD Φ12 mm – Φ38 mm. Relevant standards: ASME Section VIII, ASME B31.3, API 660 (shell-and-tube heat exchangers).

Air Conditioning and Refrigeration — Evaporator and Condenser Tube Bundle Seal Welding

Large-tonnage water-cooled chillers and industrial refrigeration systems use flooded evaporators and shell-and-tube condensers where copper-nickel, titanium, or stainless steel tubes are expanded and seal-welded into carbon steel or stainless steel tubesheets. In high-efficiency chiller designs for district cooling, process cooling, and data center chilled water plant, the tube count per heat exchanger ranges from 200 to over 1000 tubes, all requiring individual tube-to-tubesheet seal welds.

For stainless steel tube-in-stainless tubesheet applications in this sector — driven by the shift to refrigerants with higher operating pressures (R-32, R-454B, R-744) that demand stronger tube materials — the PT40 provides the same consistent seal weld quality across a 1000-tube bundle that it provides on a 50-tube laboratory heat exchanger. The 30-second clamping cycle means a single operator can complete a 500-tube bundle in a structured production schedule without the fatigue accumulation that would progressively degrade manual weld quality across the same scope. For the U-bend return joints in U-tube bundle evaporators rather than straight tube-to-tubesheet connections, see the FXT20 Pro-C U-bend orbital welder.

Compatible tube: stainless steel (304, 316L), titanium Grade 2. Tube OD Φ12 mm – Φ38 mm. Relevant standards: ASHRAE 15, ASME Section VIII, EN 378.

PT40 Tube-to-Tubesheet Orbital Welder — Frequently Asked Questions

What tube diameters does the PT40 cover, and does it require a separate head for each diameter?

The PT40 covers tube outer diameters from Φ12 mm to Φ38 mm in a single head. The standard configuration includes a 0°/7° dual-angle slide base and Φ25 mm / Φ38 mm dual-specification gas nozzles. Tubes from Φ12 mm to Φ28 mm use the 7° electrode angle; tubes from Φ25 mm to Φ38 mm use the 0° electrode angle. Switching between diameter ranges requires component replacement within the same head — no separate PT40 unit is needed for the full Φ12 mm – Φ38 mm range. For tube OD above Φ38 mm (up to Φ80 mm), special welding heads or modification kits are available on request.

How does the PT40 access tube-to-tubesheet joints inside a boiler drum or heat exchanger shell?

The PT40 head measures 300 × 150.5 × 143.5 mm and weighs 3 kg — designed to pass through the manway or access opening of a boiler drum or heat exchanger shell and extend to interior tubesheet tube rows. The 180° handle-triggered elastic collet clamps radially and axially into the tube socket in under 30 seconds without manual support. The FXT20 power source connects via 8-metre standard flexible cables, giving the operator a full working radius from the access point. For very large drums where cable length is a constraint, longer cable options are available on request.

What is the difference between the PT40 tube-to-tubesheet welder and the FXT20 Pro-C U-bend welder?

The PT40 performs butt-end tube-to-tubesheet welds — the joint where the tube end face meets the tubesheet face. The tube is inserted through the tubesheet hole (flush or slightly proud of the tubesheet face) and the weld runs circumferentially around the tube end, joining tube to tubesheet. This is the standard seal weld geometry in boilers, shell-and-tube heat exchangers, and steam generators.

The FXT20 Pro-C with C12–C25 U-bend heads performs socket fillet welds between an inserted U-bend tube and a straight tube — the return-bend joint geometry in U-tube bundle heat exchangers and liquid cooling manifolds. These are different joint geometries requiring different head designs and are not interchangeable.

Does the PT40 require filler wire for tube-to-tubesheet seal welds?

No. The PT40 is designed for autogenous (no-filler) tube-to-tubesheet seal welds, where the weld is formed entirely by melting the base metal of the tube and tubesheet face. This is the standard process for seal welds in heat exchangers and boilers where the tube is expanded into the tubesheet hole (strength from expansion) and the weld provides sealing rather than structural load-carrying. For applications requiring filler-wire strength welds or fillet weld geometry, contact FYID-Feiyide's applications team for special head configurations.

What weld documentation does the PT40 + FXT20 system produce for ASME and nuclear quality programs?

The FXT20 power source logs current, rotation speed, arc voltage, zone index, and timestamp for every weld cycle. The built-in micro printer generates a printed weld report per joint on demand; USB export enables unlimited data archiving. This output supports: ASME Section I and Section VIII Manufacturer's Data Report weld records, ASME Section III nuclear component documentation, NQA-1 and 10 CFR 50 Appendix B traceability requirements, and per-tube weld records for boiler and heat exchanger third-party inspection sign-off. The 200-group parameter library ensures every production weld replicates the qualified WPS parameters exactly.

How long does clamping and setup take per tube joint, and how many joints can one operator complete per shift?

The elastic collet clamping mechanism completes radial and axial positioning in under 30 seconds per joint — three steps (insert, lever, lock) without manual support or adjustment tools. Once the program is selected for the tube specification, the weld cycle runs automatically. On a standard boiler tube-to-tubesheet run with Φ25 mm carbon steel tube, one operator with one PT40 head typically completes 80 to 120 joints per 8-hour shift, including clamping, weld cycle, head removal, and repositioning time. With two PT40 heads running from a single FXT20 power source (in sequence), throughput increases proportionally.

For tube OD confirmation, tubesheet layout review, or WPS/PQR support for ASME Section I, Section VIII, or Section III qualification, contact FYID-Feiyide's applications engineering team. The PT40 welding head is available individually for operations already running the FXT20 power source. Special head configurations for tube OD Φ38 mm – Φ80 mm, filler wire welding, or non-standard tubesheet geometries are available on request with a 15–20 working day lead time.