A Wisconsin stainless fabricator used IronKit to generate a bid for a food-grade 316L stainless steel conveyor frame. The owner specified sanitary weld requirements (crevice-free joints, full penetration where food contact), passivation per ASTM A967, and material certifications for every heat of material used. IronKit's stainless bid template captured all these requirements in the scope section — protecting the shop from post-delivery disputes about surface finish and certification requirements.
Frequently Asked Questions
What are sanitary weld requirements for food-grade stainless?
Sanitary welds must be: (1) full penetration — no crevices where bacteria can harbor; (2) smooth profile — flush or slightly concave, no undercut or overlap; (3) passivated — ASTM A967 to remove surface iron and restore the chrome oxide layer; (4) traceable — mill certifications for every heat of material. These requirements are specified by USDA, FDA, and food plant owners.
Why does 316L cost more than 304 stainless?
316L contains 2–3% molybdenum which gives significantly better chloride corrosion resistance. In food applications where chloride sanitizers (bleach, etc.) are used, 316L is the standard. It costs approximately 15–20% more than 304 per pound. For non-food applications in mild environments, 304 is adequate and cheaper.
What is ASTM A967 passivation and is it required?
ASTM A967 passivation involves immersing stainless in nitric acid or citric acid solution to remove surface iron contamination and thicken the chrome oxide passive film. For food-grade stainless, it's required. For structural stainless, it's not required but recommended in corrosive environments. Cost: $0.15–$0.30/square foot for shop passivation.
Does IronKit include passivation as a line item?
Yes. IronKit's stainless bid template adds passivation as a separate line item when you check "food-grade" or "sanitary application" in the generator. You can specify ASTM A967 Method 1 (nitric), Method 2 (citric), or per the customer's preferred specification.