6 ASME Steam Generators for TSMC Semiconductor Fabs: How Lmart Earned a Long-Term Supplier Role with Air Products

Lmart delivered six large-format PHG830 steam generators across three phased orders for TSMC’s advanced-node semiconductor fabs in Taiwan — all to ASME U Stamp, all in Inconel 825, all on schedule.

Customer	Air Products and Chemicals, Inc.
End User	TSMC (Taiwan Semiconductor Manufacturing Company)
Project Location	Tainan Science Park, Taiwan
Phases Covered	TSMC F22 Train 2 / F22 Train 3 / Zone 29-1
Equipment	Steam Generator — PHG830 × 6 units
Unit Weight	5,200 kg each
Shell Dimensions	DN1772 × THK10 × L4482 mm
Design Code	ASME Section VIII Div. 1 — U Stamp
Shell Material	SB424 N08825 (Inconel 825) / Duplex 2205
Tube Material	N08825 (Inconel 825)
Application	Ultra-high-purity industrial gas supply for chip manufacturing

Customer Background and Industry Context

TSMC is the world’s largest contract semiconductor foundry, producing the advanced chips that power smartphones, AI accelerators, and high-performance computing systems. Its fabs operate at process nodes as tight as 3nm and 5nm, requiring manufacturing environments with essentially zero tolerance for contamination, vibration, or process interruption.

Industrial gas is the lifeblood of semiconductor fabrication. Hydrogen, nitrogen, and specialty gases are consumed in enormous volumes across deposition, etching, and cleaning processes — and they must be delivered continuously, at controlled purity, without a single unplanned interruption. TSMC’s gas supply contracts go to a small number of established global suppliers. Air Products is one of those partners, operating dedicated on-site gas generation and purification systems adjacent to TSMC’s fab buildings.

The equipment that bridges high-pressure gas supply to fab-side process conditions — including steam generators used in thermal management and gas conditioning — must meet the same reliability standard as the fab itself. A failure in gas supply infrastructure can halt production lines, resulting in wafer losses measured in millions of dollars per hour.

TSMC’s fabs are not built in one phase. The company expands capacity continuously, adding production trains as demand grows. This phased construction model creates a specific procurement challenge: suppliers must deliver precision-matched equipment across multiple orders separated by months or years, with no variation in quality or dimensional tolerances between units.

Challenges and Engineering Pain Points

Zero-Downtime Infrastructure

Semiconductor fabs run 24 hours a day, 365 days a year. The gas supply systems feeding them are expected to match that availability. Any steam generator entering this supply chain must be designed for long service life with no unplanned maintenance windows. This places exceptional demands on material selection, weld quality, and tube bundle integrity — not just for the first unit, but for every unit in a multi-phase delivery.

Ultra-Clean Process Environment

Inconel 825 was specified for both shell and tube materials — not because it was the cheapest option, but because it is the right metallurgical answer for this service environment. The alloy’s resistance to stress corrosion cracking, pitting, and crevice corrosion in high-purity process fluids is well established. Any deviation in material certification, heat number traceability, or surface finish at the tube-to-tubesheet joint is unacceptable.

Phased Delivery Across Multiple Orders

The three purchase orders — F22 Train 2 (1 unit), F22 Train 3 (3 units), and Zone 29-1 (2 units) — were placed at different times, tied to TSMC’s rolling fab construction schedule. Each delivery had to arrive in coordination with civil and mechanical completion milestones at the fab site.

Dimensional and Quality Consistency Across All 6 Units

When Air Products commissions multiple identical units in a single system — or when they replicate a proven design across expansion phases — dimensional and functional consistency is mandatory. Tube bundle geometry, nozzle orientation, shell thickness, and hydrotest results must be reproducible to the same standard unit after unit.

Why Air Products Selected Lmart

Lmart was not chosen speculatively for this project. The relationship was established on the basis of demonstrated capability in large-format ASME pressure vessel fabrication, and the selection was reinforced through performance on each successive order.

ASME U Stamp authorization. Air Products’ global engineering standards require ASME Section VIII Div. 1 certification for vessels in this service category. Lmart holds active ASME U Stamp authorization, with an in-house Authorized Inspector program and full ASME documentation package.

Large-diameter vessel capability. The PHG830 shell at DN1772mm (approximately 1.77 meters diameter) places these vessels in a size range that challenges many fabricators. Lmart’s workshop infrastructure — plate rolling, shell alignment, and post-weld heat treatment capacity — handles this diameter without constraint.

Proven Inconel 825 fabrication. Working with SB424 N08825 plate and tube requires qualified WPS/PQR documentation, trained welders with active certifications, and a quality system that tracks heat numbers from raw material receipt to final inspection.

Repeat-build reliability. When Air Products placed the second and third orders, the answer they needed was confirmation that the same drawings, the same qualified procedures, and the same manufacturing team would produce units indistinguishable from the first. Lmart delivered that assurance.

Engineering and Manufacturing Solution

The PHG830 is a large-format shell-and-tube steam generator optimized for continuous-duty industrial gas conditioning service. At 5,200 kg per unit and 4,482mm overall length, it represents the upper end of the standard PHG product range.

Material strategy. Shell construction uses SB424 N08825 plate with Duplex 2205 in structural transition zones, combining Inconel 825’s corrosion resistance with the mechanical strength of duplex stainless. The full tube bundle is N08825, maintaining a consistent corrosion-resistant surface throughout the heat transfer circuit.

Why Inconel 825? Material Selection Rationale

Property	316L SS	Inconel 825 (N08825)	Inconel 625 (N06625)
SCC Resistance	Poor — fails in chloride environments	Excellent	Superior
Pitting Resistance (PREN)	~25	~33	~51
Max Service Temp	~450 °C	~540 °C	~650 °C
Weldability	Excellent	Good — requires qualified WPS	Good — requires qualified WPS
Relative Material Cost	1×	3–4×	6–8×
Typical Application	General chemical service	H&sub2;/syngas, high-purity gas, sulfuric acid	Subsea, ultra-high corrosion

For this service — high-purity hydrogen generation with mixed acid condensate — Inconel 825 provides the required corrosion resistance at roughly half the cost of Inconel 625, making it the engineering-optimal choice.

Tube bundle design. The bundle geometry is optimized for the thermal cycling inherent in steam generation service — start-up, load variation, and controlled shutdown sequences that create differential expansion between shell and tubes.

Standardized manufacturing for repeat builds. After the first unit (F22 Train 2), Lmart locked the manufacturing package: WPS/PQR documentation, nozzle schedules, weld maps, heat treatment records, and dimensional inspection reports. Each subsequent unit was produced against the same locked package, with serialized traceability.

ASME documentation. Each unit shipped with a complete ASME U Stamp data package: Manufacturer’s Data Report (Form U-1), National Board registration number, hydrostatic test certificate, material traceability records, and final dimensional inspection report.

Project Execution, Quality Control, and Delivery

Production across the three orders was managed to respect the independence of each purchase order while leveraging the efficiency of sequential manufacturing. The first unit established the full production baseline.

Key QC milestones for each unit:

• Incoming material verification: heat number confirmed against MTR, PMI spot check on N08825 plate and tube
• Dimensional check at shell roll, before and after longitudinal seam weld
• Full radiographic examination of all butt welds per ASME requirements
• Tube-to-tubesheet joint pull test and visual inspection
• Hydrostatic pressure test witnessed by Authorized Inspector
• Final dimensional survey against certified drawings
• ASME U Stamp application by AI following Data Report sign-off

Delivery timing for each phase was coordinated with Air Products’ logistics and site construction schedules. Vessels were shipped under sea freight with appropriate crating and corrosion protection for tropical climate transit to Taiwan.

Results and Business Impact

Six PHG830 steam generators were delivered across three purchase orders, all conforming to the same design standard, all carrying ASME U Stamp certification, and all delivered on schedule to match TSMC’s fab expansion milestones at Tainan Science Park.

These units are now operating in active gas conditioning service supporting TSMC’s advanced node production — including fabs running at 3nm and 5nm process nodes that represent the global frontier of semiconductor manufacturing.

For Lmart, the Air Products relationship has established Lmart as a qualified, repeat-trusted manufacturer for semiconductor gas infrastructure — a customer segment with sustained capital investment, high technical standards, and a strong preference for suppliers who have proven they can perform repeatedly across multi-phase projects.

Customer Voice

Air Products placed three consecutive repeat orders with Lmart over a four-year period for identical equipment serving the same end user — the strongest form of supplier endorsement in capital equipment procurement.

“The documentation package, the material traceability, and the consistency between units gave our commissioning team exactly what they needed.”

— Air Products project engineering team (paraphrased from order review feedback)

Note: Lmart respects client confidentiality. Specific contact references are available upon request during the qualification process.