Northern Manufacturing fabricates custom food-grade stainless steel equipment for food and beverage OEMs, equipment integrators, and processing plants. Primary material: 316L stainless steel. Primary welding process: GTAW (TIG) to produce crevice-free sanitary welds that pass 3-A and ASME BPE inspection. All work runs through our 40,000 sq ft stainless-only production space in Oak Harbor, Ohio, where dedicated tooling, consumables, and welders prevent carbon steel cross-contamination on every assembly.
60+ AWS-certified welders. ISO 9001:2015 certified (AVU Registrations). ASME BPVC Section IX qualified welding procedures for P8 austenitic stainless. In-house pickling and passivation per ASTM A380/A967 in a 55-foot spray booth.
Equipment We Build for Food and Beverage
Northern regularly fabricates the following for food and beverage applications:
- Mixer housings and agitator vessels. 316L construction with crevice-free interior welds, tight flatness tolerances on mating flanges, and surface finishes specified to the customer’s sanitary standard.
- Sanitary process tanks. Batch tanks, hold tanks, and CIP (clean-in-place) vessels built to 3-A or ASME BPE design requirements. Interior weld surfaces ground and blended to eliminate crevices.
- CIP skids and wash systems. Skid-mounted stainless assemblies with piping, valving, and tank integration, fabricated as a unit and tested before shipment.
- Conveyor frames and structural supports. Stainless structural work for processing lines where washdown exposure demands corrosion resistance from the frame, not just the product-contact surfaces.
- Custom hoppers, chutes, and transitions. Sheet and plate fabrications with smooth interior surfaces for product flow and cleanability.
Why 316L for Food Contact
304L handles most food processing environments, but 316L is the standard choice for equipment that contacts acidic foods, brines, high-chloride cleaning agents, or sustained moisture. The molybdenum addition in 316L improves resistance to chloride pitting and crevice corrosion, which matters in equipment that is regularly cleaned with caustic or acid solutions.
| Grade | Chloride tolerance | Typical application | Cost vs. 304L |
|---|---|---|---|
| 304L | Low-moderate chloride, dry environments | Structural frames, ductwork, non-contact surfaces | Baseline |
| 316L | Moderate-high chloride, wet/acidic | Product-contact surfaces, tanks, piping, CIP systems | ~15-20% premium |
We stock 316L plate from 20-gauge through 1 inch in standard sheet sizes, with 2-day availability from our distributor network. Heavy plate (1-1/4 inch through 2 inches) is available within 5 days.
Sanitary Welding: GTAW for Crevice-Free Joints
Food-grade fabrication lives or dies at the weld. A weld bead with undercut, overlap, or incomplete penetration creates a crevice where bacteria colonize and cleaning solutions cannot reach. For product-contact surfaces, Northern specifies full-penetration GTAW (TIG) welding with autogenous or matching filler rod to produce smooth, crevice-free joints that pass visual and borescope inspection.
All welding procedures are qualified per ASME BPVC Section IX for P8 austenitic stainless. Welders hold active qualifications to AWS D1.6 (Structural Welding Code for Stainless Steel) and are recertified on a continuous cadence. When your drawing calls out a specific WPS, procedure qualification records and welder continuity logs are available on request.
Surface Finish and Passivation
Surface finish on food-contact stainless is not cosmetic: it determines cleanability, bacterial adhesion, and corrosion resistance. Northern controls surface finish from forming through final delivery.
- Mechanical finishing. We hold specified Ra (roughness average) values through controlled grinding and polishing sequences. Common finishes range from #4 satin to mirror polish, depending on the application.
- Pickling and passivation. Post-weld pickling removes heat tint and restores the chromium oxide passive layer that gives stainless its corrosion resistance. Our 55-foot spray booth handles entire assemblies in one pass per ASTM A380 and ASTM A967. No sectioning, no re-welding after treatment.
- Electropolishing. For applications requiring the lowest possible surface roughness and maximum corrosion resistance, we coordinate electropolishing as a controlled finishing step.
Contamination Control
Carbon steel contamination on food-grade stainless is not a cosmetic defect. Free iron particles embedded during grinding, forming, or handling initiate surface corrosion that can contaminate product and fail sanitary audits.
Northern operates a 40,000 sq ft stainless-only production space. Tooling, grinding wheels, clamps, work tables, and consumables are dedicated to stainless. No carbon steel work runs in this space. Free-iron verification per ASTM A380 is performed on critical-service assemblies before passivation.
Quality Documentation
Every food and beverage project ships with a documentation package built for your quality audit:
- Material Test Reports (MTRs) traced by heat number from mill cert to final assembly
- Weld maps with WPS references for every joint
- Welder continuity logs confirming active qualification status at time of fabrication
- Dimensional inspection reports per your drawing tolerances
- Pickling and passivation certification per ASTM A380/A967
- Certificate of Conformance (CoC) to your purchase order requirements
Extended documentation available on request: PMI (positive material identification) records, radiographic testing reports, ferrite content measurement, and surface roughness (Ra) verification.
Featured Project: Mixer Housing for a Food and Beverage OEM
A food and beverage equipment OEM was seeing stainless weld joints fail in the field within months. Root cause: the previous fabricator had not adjusted joint geometry for the sanitary service environment. Northern redesigned the weld joints for full-penetration GTAW, formed the housings to 0.030-inch flatness tolerance, and pickled and passivated per ASTM A380 in our 55-foot booth.
Result: zero NCRs, passed radiographic inspection on first submission. The customer returned with repeat orders and specified Northern as the sole fabricator for that housing family.
