Northern Manufacturing fabricates custom stainless and high-nickel alloy equipment for power generation facilities, refineries, chemical processing plants, and EPC firms managing capital projects in corrosive environments. Materials range from standard austenitic grades (304, 316L) through duplex (2205, 2507) and into high-nickel alloys (Hastelloy C-276, C-22, AL-6XN) for aggressive chemical service. All welding is performed in our 40,000 sq ft stainless-only production space in Oak Harbor, Ohio.
60+ AWS-certified welders. ISO 9001:2015 certified (AVU Registrations). ASME BPVC Section IX qualified welding procedures for P8 (austenitic), P10H (duplex), P43 (Hastelloy), and P45 (AL-6XN). CWI on staff. In-house pickling and passivation per ASTM A380/A967.
Equipment We Build for Power, Energy, and Chemical
- Exhaust ductwork. Large-diameter stainless ductwork for power generation exhaust systems. Factory dry-fit against mating sections before shipment to eliminate forced alignment on site.
- Reactor internals and process vessels. Internal baffles, trays, distribution piping, and vessel components in corrosion-resistant alloys matched to the process chemistry.
- Process piping and spools. Prefabricated pipe spools with full weld documentation, NDE, and dimensional verification. Alloys selected for the service temperature and chemical exposure.
- Heat exchanger components. Tube-to-tubesheet welds in corrosion-resistant alloys where joint geometry and heat input control determine equipment lifespan.
- Structural components and platforms. Stainless structural work for process environments where carbon steel corrodes under chemical exposure or washdown conditions.
- Scrubbers and air-quality equipment. Gas-contact surfaces fabricated in high-nickel or duplex alloys for sustained acid-dew-point exposure.
Material Selection for Chemical and High-Temperature Service
Material selection in power and chemical processing is driven by the specific chemistry, temperature, and pressure your equipment will see. Decades of fabrication in these environments have established clear starting points:
| Grade | Best for | Why |
|---|---|---|
| 316L | Mild chemical environments, moderate temperatures | Good general corrosion resistance; cost-effective baseline |
| Duplex 2205 | Chloride-bearing streams, caustic solutions | 2x yield strength of 316L; resists chloride SCC |
| Duplex 2507 | Severe chloride, hot seawater, high-pressure lines | Superior pitting resistance where 2205 is marginal |
| Hastelloy C-276 | Concentrated acids (sulfuric, HCl, phosphoric), wet chlorine gas | Resists both oxidizing and reducing acids |
| Hastelloy C-22 | Mixed-acid environments, oxidizing-reducing transitions | Broader corrosion resistance than C-276 in mixed chemistries |
| AL-6XN | Severe chloride pitting, warm brackish water | Super-austenitic with 6% molybdenum for pitting resistance |
Northern has qualified welding procedures and production experience across all of these alloys. If you are not sure which grade fits your application, we can review your process conditions and recommend options.
Welding High-Nickel and Duplex Alloys
High-nickel alloys and duplex stainless punish fabrication shortcuts. Each family has specific metallurgical constraints that standard welding procedures do not address:
Duplex (2205, 2507): Excessive heat input destroys the 50/50 austenite-ferrite balance, creating brittle sigma phase. We control interpass temperature and use matching filler (ER2209 for 2205, ER2594 for 2507) with ferrite measurement on production weldments.
Hastelloy (C-276, C-22): These alloys are susceptible to hot cracking and segregation in the weld metal. We use low-heat-input GTAW with tight bead-width control and matching filler (ERNiCrMo-4 for C-276, ERNiCrMo-10 for C-22).
AL-6XN: The high molybdenum content makes AL-6XN prone to microsegregation during welding. We use overmatching filler (ERNiCrMo-3) to maintain corrosion resistance in the weld zone.
Contamination Control and Surface Restoration
Cross-contamination between carbon steel and corrosion-resistant alloys is a failure mode, not a cosmetic issue. In chemical service, embedded iron particles initiate crevice corrosion at the contamination site.
Northern operates a 40,000 sq ft stainless-only production space with dedicated tooling, grinding wheels, and work surfaces. Post-weld pickling per ASTM A380 restores the passive layer. PMI (positive material identification) confirms alloy identity on incoming material and on completed weldments.
Quality Documentation
- Material Test Reports (MTRs) with full heat traceability
- Weld maps with WPS/PQR references
- PMI records (positive material identification) for alloy verification
- NDT reports (RT, UT, PT, or MT as specified)
- Ferrite measurement records for duplex welds
- Dimensional inspection and fit-up verification
Featured Project: Power Generation Exhaust Ductwork
A power generation facility needed replacement exhaust ductwork with large-diameter sections that had to mate to existing in-plant flanges during a scheduled outage. Field labor was the expensive constraint: every hour of forced alignment on site drove six-figure impact.
Northern factory dry-fit every assembly against its mating section before release. Field crews installed the duct run without rework, with sections dropping into position on the first attempt.
