Chemical processing environments punish material mistakes. Concentrated acids eat through carbon steel in weeks. Chloride-bearing streams cause stress corrosion cracking in the wrong stainless grades. Mixed-acid conditions attack weld zones that looked perfect during hydro test but fail within months of service. Northern Manufacturing has fabricated chemical processing equipment in corrosion-resistant alloys since 1951, and we understand what these environments demand from both the material and the fabricator.

We build reactor vessels, heat exchangers, piping systems, storage tanks, scrubbers, and mixing vessels for chemical plants, refineries, and specialty chemical producers across the country. Every project starts with the same question: what is this equipment going to contact, at what temperature, and for how long?

Equipment We Fabricate for Chemical Processing

Chemical processing covers a broad range of equipment, and the fabrication challenges vary by application. Northern regularly builds:

• Reactor vessels and process tanks: Tight-tolerance shell courses, nozzle reinforcements, and internal baffles fabricated with ASME-qualified welding procedures. Weld integrity is non-negotiable when operating with corrosive media.
• Heat exchangers: Tube-to-tubesheet welds in corrosion-resistant alloys, where joint geometry and heat input control determine whether the unit lasts two years or twenty.
• Piping systems and spools: Prefabricated pipe spools with full weld documentation, NDE, and fit-up verification before they ship to the job site.
• Storage tanks and process tanks: From small batch tanks to large-capacity vessels, built to the corrosion allowances and surface finish requirements the application demands.
• Scrubbers and pollution control equipment: Gas-contact surfaces that face some of the most aggressive chemical conditions in any plant. Material selection here separates equipment that performs from equipment that gets replaced.
• Mixing vessels and agitator tanks: Internal surface finish, baffle welding, and nozzle placement all affect process performance. We work from your engineering drawings or collaborate on design-assist projects.

Why Material Selection Drives Everything in Chemical Service

The wrong alloy in a chemical environment is not a maintenance problem. It is a safety problem, a production problem, and an insurance problem. Three failure modes account for most chemical equipment corrosion issues:

Chloride stress corrosion cracking (SCC) is the most common reason standard 304 and 316 stainless fails in chemical plants. Even trace chloride levels at elevated temperatures can initiate cracking in austenitic grades. Duplex 2205 offers roughly twice the yield strength of 316L with far superior chloride SCC resistance, making it the standard choice for chloride-bearing chemical streams.

Acid attack destroys the passive layer that gives stainless steel its corrosion resistance. Concentrated sulfuric, hydrochloric, and hydrofluoric acids require alloys specifically engineered for those environments. Hastelloy C-276 handles reducing acids, oxidizing acids, and chloride-contaminated acid mixtures that would destroy conventional stainless grades. For mixed-acid environments where both oxidizing and reducing conditions exist, Hastelloy C-22 provides broader resistance across a wider pH range.

Pitting and crevice corrosion targets weld zones, gasket surfaces, and any geometry that traps stagnant fluid. AL-6XN (a super-austenitic 6% molybdenum alloy) resists pitting in warm chloride solutions where 316L fails, and it welds with conventional GTAW techniques that our team runs daily.

Grade Recommendations by Application

Material selection always depends on the specific chemistry, temperature, and concentration your equipment will see. That said, decades of chemical processing fabrication have established clear starting points:

• 316L: Mild chemical environments, food-grade chemical processing, pharmaceutical intermediates. Good general corrosion resistance at moderate temperatures.
• Duplex 2205: Chloride-bearing streams, caustic solutions, process water with elevated chlorides. Higher strength allows thinner wall sections, reducing weight and material cost.
• Duplex 2507: Severe chloride environments, hot seawater, high-pressure chemical lines where 2205 is marginal.
• Hastelloy C-276: Concentrated acids (sulfuric, hydrochloric, phosphoric), wet chlorine gas, chloride-contaminated acid streams.
• Hastelloy C-22: Mixed-acid environments, oxidizing-reducing transitions, pharmaceutical process vessels exposed to multiple chemical streams.
• AL-6XN: Severe chloride pitting conditions, warm brackish water, chemical plant utility systems where 316L pits.

Our team works with all of these alloys regularly. If you are not sure which grade fits your application, we can review your process conditions and recommend options based on what we have seen work (and fail) in similar service.

Fabrication Challenges Specific to Chemical Equipment

Building equipment for chemical service is not the same as building structural stainless. The fabrication itself introduces risks that a general shop may not account for:

Weld integrity in corrosive service: Every weld in a chemical vessel is a potential failure point. The heat-affected zone has different metallurgy than the base metal, and in corrosive service, that difference matters. Our welding team includes 60+ AWS-certified welders with qualified procedures for every alloy we run. Our CWI and ASNT Level III NDE technicians verify weld quality to the code and standard your project requires.

Contamination control: A single carbon steel particle embedded in a stainless surface will rust and initiate crevice corrosion. In chemical service, that small defect becomes a leak path. Northern operates a dedicated stainless-only production space where no carbon steel enters. Your chemical processing equipment is fabricated, ground, and finished without exposure to carbon contamination.

Surface finish requirements: Many chemical applications specify interior surface finishes (measured in Ra) that affect cleanability, product purity, and corrosion resistance. We control surface finish through mechanical polishing, bead blasting with stainless media, and chemical treatment. Our 55-foot pickling and passivation booth handles oversized assemblies that other shops send out, keeping your project under one roof and one quality system.

Positive Material Identification (PMI): When your spec calls for C-276 and someone accidentally welds a 316 nozzle, the consequences in acid service are catastrophic. We verify alloy identity with PMI testing on incoming material and completed assemblies, so the material certs match what is actually in your equipment.

What Northern Brings to Chemical Processing Projects

Chemical processing equipment fabrication requires a shop that understands corrosion metallurgy, not just welding procedures. Northern Manufacturing is an ISO 9001:2015 certified stainless steel fabricator with ASME-qualified welding procedures across the full range of corrosion-resistant alloys. Our 160,000 sq ft facility includes dedicated stainless-only production space, in-house pickling and passivation, and a quality program built for code work in critical-service applications.

We have fabricated equipment for chemical plants, petrochemical facilities, specialty chemical producers, and EPC firms managing capital projects in corrosive environments. Whether you need a single reactor vessel in Hastelloy or a full equipment package in duplex, we have the alloy experience, welding certifications, and quality infrastructure to deliver it.

Have a chemical processing project? Request a quote and tell us what you are building, what it contacts, and what code governs the work. We will take it from there.