Northern Manufacturing fabricates sanitary stainless steel equipment for food, beverage, pharmaceutical, and personal care processors: vessels, CIP skids, hygienic conveyors, and process piping where preventing contamination is the whole job. Product-contact welds are full-penetration GTAW, ground and blended crevice-free. Surface finishes are held to the Ra your specification calls out. Every assembly runs through our 40,000 sq ft stainless-only production space in Oak Harbor, Ohio, and finishes with pickling and passivation per ASTM A380/A967 in our 55-foot spray booth.
60+ AWS-certified welders. ISO 9001:2015 certified (AVU Registrations). Welding procedures qualified per ASME BPVC Section IX for P8 austenitic stainless, with welder qualifications to AWS D1.6. Material traceability by heat number from mill cert to final assembly.
What We Build for Sanitary Service
- Mixing tanks, vessels, and bioreactor bodies. Custom-fabricated stainless containers with smooth, crevice-free interior surfaces for mixing, holding, or cultivating sensitive product.
- CIP skids and skid-mounted process systems. Clean-in-place systems and other pre-assembled modules built on a portable stainless frame, fabricated and fit as a unit before shipment.
- Hygienic conveyors and augers. Screw conveyors and material handling frames designed for washdown exposure and built so bulk product moves without hanging up in corners or seams.
- Sanitary process piping and valve manifolds. GTAW-welded stainless piping, tubing runs, and valve clusters for hygienic fluid transfer.
- Custom hoppers, chutes, and transitions. Sheet and plate fabrications with smooth interior surfaces for product flow and cleanability.
Crevice-Free Welding for Product-Contact Surfaces
A sanitary weld failure does not look like a structural weld failure. A microscopic crevice from undercut, overlap, or incomplete penetration becomes a harbor for bacteria, and the resulting biofilm survives CIP cycles that clean every other surface in the system. That risk is fabrication-controlled, so it is where our process is strictest.
Product-contact welds at Northern are full-penetration GTAW (TIG), made by welders qualified per ASME BPVC Section IX for P8 austenitic stainless. Interior weld surfaces are ground and blended to eliminate crevices, then verified by visual and borescope inspection. Every joint carries a WPS reference on the weld map, so your quality team can trace any weld on the assembly back to the qualified procedure and the welder who made it.
Holding a Specified Ra
Surface roughness on product-contact stainless determines cleanability and bacterial adhesion, not appearance. We control finish from forming through final delivery: controlled grinding and polishing sequences hold specified Ra values, with common finishes running from #4 satin to mirror polish depending on the service. Where the specification requires it, measured Ra verification ships in the documentation package.
After mechanical finishing, assemblies are pickled and passivated per ASTM A380 and ASTM A967 in our 55-foot spray booth. Pickling strips weld heat tint and the chromium-depleted layer underneath it; passivation restores the chromium-oxide layer that gives stainless its corrosion resistance. Whole assemblies go through in one pass, so there is no sectioning and re-welding after treatment.
Material Selection for Cleaning Chemistry
Most sanitary equipment is 316L, and for good reason: the molybdenum addition resists the chloride pitting that acidic products and caustic cleaning agents cause in 304L. But the right grade depends on your process chemistry, and we will tell you when the answer is not the default.
| Grade | When to specify it |
|---|---|
| 304L | Frames, supports, and non-contact surfaces in dry or low-chloride environments |
| 316L | Product-contact surfaces, tanks, piping, and CIP systems; the sanitary workhorse |
| AL-6XN | High-chloride process or cleaning chemistry, especially warm chlorides where 316L pits |
| Hastelloy C-22 / C-276 | Aggressive mixed-acid or reducing-acid service beyond what super-austenitic grades handle |
We stock 316L plate from 20-gauge through 1 inch with 2-day availability from our distributor network; heavy plate through 2 inches is available within 5 days. Specialty grades like AL-6XN are sourced per project.
Contamination Control by Separation
Free iron on sanitary stainless is a latent defect. Particles embedded by shared grinding wheels or carbon-steel fixtures pass visual inspection at shipment, then corrode in service and seed pitting in the stainless around them.
Northern runs sanitary work through a 40,000 sq ft stainless-only production space. Tooling, abrasives, clamps, and work tables in that room never touch carbon steel. Free-iron verification per ASTM A380 is performed on critical-service assemblies before passivation, and the passivation certificate ships with the equipment.
Documentation Built for Your Audit
Sanitary buyers do not just need clean equipment, they need proof of it. Every project ships with a turnover package assembled under our ISO 9001:2015 quality system:
- Material Test Reports (MTRs) traced by heat number from mill cert to final assembly
- Weld maps with WPS references for every joint, plus welder continuity logs
- Surface finish (Ra) verification where the specification requires it
- Pickling and passivation certification per ASTM A380/A967
- Dimensional inspection reports to your drawing tolerances
- Certificate of Conformance (CoC) to your purchase order requirements
When a customer audit or regulatory inspection asks how a weld was made or where the material came from, the answer is already in the binder.
