ASME Steam Generator for ArcelorMittal Brazil: Inconel 825 & Duplex 2205 in High-Temperature Steel Plant Service

End User	ArcelorMittal — world’s largest steel producer
Procurement Client	Air Products
Project	Arcelor Brazil Project
Equipment	1× Steam Generator
Weight	1,560 kg
Dimensions	DN762 × THK10 × L2285 mm
Design Standard	ASME Section VIII Division 1 — U Stamp
Shell Material	SB424 N08825 (Inconel 825) / Duplex 2205
Tube Material	N08825 (Inconel 825)
Application	Industrial gas & hydrogen supply for steel production
Destination	Brazil (Espírito Santo state complex)

Supporting the World’s Largest Steelmaker with Code-Compliant, Corrosion-Resistant Process Equipment

Customer Background: Gas Infrastructure at the Heart of Steel Production

ArcelorMittal is the world’s number-one steelmaker by output, with major integrated steel complexes across Europe, the Americas, and Africa. Its Brazilian operations — centered on the Tubarão and Serra complexes in Espírito Santo — represent some of the largest flat steel production facilities in South America, supplying automotive, construction, and energy-sector customers across the continent.

Industrial gases are a critical utility in integrated steelmaking. Oxygen drives blast furnace combustion and electric arc furnace (EAF) efficiency. Nitrogen provides inert blanketing for sensitive process streams. Hydrogen is central to Direct Reduced Iron (DRI) and Hot Briquetted Iron (HBI) production — technologies that reduce carbon intensity versus conventional blast furnace routes. With decarbonization pressure building across the global steel industry, hydrogen demand at sites like ArcelorMittal Brazil is only growing.

Air Products, one of the world’s largest industrial gas companies, operates on-site gas generation and supply infrastructure at major steel complexes worldwide. For the Arcelor Brazil project, Air Products required a steam generator capable of sustaining reliable process performance in the aggressive thermal and chemical environment typical of steel plant gas installations — and it needed to meet ASME code requirements accepted in Brazil’s industrial regulatory framework.

The Challenge: Corrosive Service, Continuous Duty, Long-Distance Export

Supplying process equipment to a steel plant is not the same as supplying to a chemical plant or a marine application. Steel facilities impose a uniquely demanding combination of conditions:

Corrosive gas exposure. Steel plant off-gases — blast furnace gas, coke oven gas, and converter gas — contain hydrogen sulfide, sulfur dioxide, ammonia, chlorides, and other aggressive species. Any steam generator operating within or adjacent to these streams must resist corrosion at both the tube-side and shell-side surfaces over a multi-year service life without intervention.

Continuous, uninterrupted operation. Integrated steel production runs 24 hours a day, 365 days a year. An unplanned shutdown in the gas supply system cascades immediately into production losses worth millions of dollars per day. Air Products’ engineering standards for equipment placed in this environment demand verified material integrity, weld quality, and test documentation — not just compliance on paper.

ASME certification for South American export. Brazil recognizes ASME Section VIII Division 1 as the accepted pressure vessel code for industrial gas applications, and Air Products’ global procurement policy requires ASME U Stamp certification regardless of the manufacturing origin. Sourcing from China means the manufacturer must hold an active ASME Certificate of Authorization, maintain the quality management system required for National Board registration, and produce full Data Reports — a level of documentation that disqualifies most Chinese fabricators before the project even begins.

Ocean freight to South America. Equipment shipped from Jiangsu to Brazilian ports faces a transit time of five to seven weeks, port handling at Santos or Vitória, and overland transport to the site. The packaging must protect precision flange faces, nozzle connections, and tube-bundle integrity against humidity, salt air, mechanical shock, and compression loading throughout the journey.

Why Air Products Chose Lmart

Air Products had worked with Lmart on multiple prior projects before the Arcelor Brazil award, spanning steam generators, heat exchangers, and pressure vessels across different geographic markets. That history established a documented track record across several key dimensions.

Active ASME U Stamp authorization. Lmart holds a current ASME Certificate of Authorization for Section VIII Division 1 pressure vessels, maintained under the continuous audit program required by the ASME Boiler and Pressure Vessel Committee. Air Products’ engineering team could rely on Lmart’s ASME quality system — including Authorized Inspector oversight, documented design calculations, and National Board-registered Data Reports — as a known quantity rather than an unknown risk.

Demonstrated experience with high-alloy and corrosion-resistant materials. Lmart’s production history in N08825 (Inconel 825), Duplex 2205, and similar alloys is verifiable through prior Air Products project records. Welding of nickel alloys and duplex stainless steels requires qualified procedures, trained welders, and controlled interpass temperature management that not all ASME shops can execute consistently.

Commercial and logistical reliability. On-time delivery and accurate export documentation are table stakes for an international gas company procuring from China. Lmart’s track record with Air Products on prior shipments — including CRN-registered equipment for Canada and ASME units for Korea — gave the procurement team confidence that the Brazil unit would arrive on schedule and with complete paperwork.

Engineering Solution: Material Selection for Steel Plant Service

The selection of SB424 N08825 (Inconel 825) for both the shell and the tubes reflects a deliberate engineering decision for the expected service environment.

Inconel 825 (UNS N08825) is a nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. Its composition is specifically engineered for resistance to sulfuric acid, phosphoric acid, hydrogen sulfide, and chloride-bearing environments — exactly the contaminant profile found in steel plant gas streams. The alloy maintains corrosion resistance across a wide temperature range and is significantly more resistant to stress corrosion cracking than austenitic stainless steels such as 316L. For tube material in a heat exchanger or steam generator where the tube-side fluid carries aggressive gas species, N08825 is the standard solution in gas supply infrastructure at integrated steel facilities.

Duplex 2205 was specified for structural components of the shell assembly where its combination of high yield strength and corrosion resistance provides a cost-effective structural solution for non-wetted or moderately exposed surfaces. Duplex 2205 offers approximately twice the yield strength of 316L stainless steel, allowing reduced wall thickness without compromising pressure containment under the thermal cycling inherent in steam generation service.

The equipment geometry — DN762 shell diameter, 10 mm wall thickness, 2,285 mm overall length — was established through Lmart’s engineering review of the process duty specified by Air Products, including operating pressure, steam generation rate, and fluid inlet conditions. Design calculations were performed per ASME Section VIII Division 1 requirements and reviewed by the Authorized Inspector prior to fabrication release.

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.

Execution and Quality Control

Fabrication of the Arcelor Brazil steam generator followed Lmart’s ASME quality program from raw material receipt through final shipping:

Material traceability. All SB424 N08825 plate and tube material was procured with certified mill test reports traceable to the heat number, verified against ASME material specifications, and recorded in the project quality dossier. Duplex 2205 components were similarly certified and segregated during storage to prevent cross-contamination.

Welding qualification. Welding Procedure Specifications (WPS) and Procedure Qualification Records (PQR) for N08825-to-N08825 and dissimilar-metal welds were reviewed and approved before production welding commenced. Welder qualification records were verified current for all operators assigned to the vessel.

Non-destructive examination. Radiographic testing (RT) was performed on all full-penetration pressure boundary welds in accordance with the ASME Section VIII Division 1 requirements applicable to the vessel’s design classification. Liquid penetrant testing (PT) was applied to accessible weld surfaces including nozzle attachment welds on the N08825 components.

Hydrostatic pressure test. The completed vessel was hydrostatically tested at 1.3 times design pressure — the ASME minimum test multiplier — with the Authorized Inspector (AI) present throughout the test. Test pressure, duration, and result were recorded in the Manufacturer’s Data Report (Form U-1).

Packaging for ocean export. Flange faces were protected with plywood blanks and foam padding. Nozzle openings were capped and taped. The vessel was mounted on a custom timber cradle rated for the 1,560 kg lifting and transport loads, with steel banding and corner protectors. A desiccant pack and humidity indicator were placed inside the shell before the end caps were fitted, providing a measurable record of moisture ingress during transit.

Results: Operational Steam Supply at the ArcelorMittal Complex

The steam generator was delivered to the ArcelorMittal Brazil site on schedule, cleared Brazilian customs with complete ASME documentation, and was commissioned as part of Air Products’ gas supply infrastructure at the complex. The unit entered service supporting the industrial gas and hydrogen supply systems that underpin steel production at the facility.

For Air Products, the outcome confirmed that Lmart could execute a high-alloy, ASME-certified vessel for a demanding end-user environment and deliver it reliably to South America — a combination of technical capability and logistical execution that narrows the qualified supplier pool considerably.

Customer Voice

Air Products selected Lmart for this project based on demonstrated capability and placed the order through a competitive qualification process — the strongest form of supplier endorsement in capital equipment procurement.

“The Lmart team understood from the start that this wasn’t a standard carbon steel job. The material handling, weld procedures, and NDT coverage for the N08825 components were all correct the first time, and the ASME documentation package was clean and complete. That made the Authorized Inspector sign-off and the Brazilian import process straightforward. The unit arrived in good condition and went into service without issues.”

— Site Engineer, Air Products (Arcelor Brazil Project) (paraphrased from project review feedback)

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