Background and Problem
Stainless steel cutlery manufacturing involves multiple stages of mechanical working — pressing, grinding, buffing, and polishing — each of which applies lubricants, compounds, and heat to the metal surface. After the final polishing stage, stainless steel cutlery should present a bright, uniform, corrosion-resistant surface.
The client was experiencing 9% rejection at final inspection — a mix of yellowish discolouration, white oxide deposits, and early rust spots appearing within 48–72 hours of final polishing. These defects were not present immediately after polishing but developed during the inspection and staging period before packing.
REFA’s audit identified two compounding problems. First, the cleaning after polishing was removing buffing compound but leaving a thin, oxygen-depleted surface layer that was not adequately passivated — the chromium oxide layer that gives stainless steel its corrosion resistance was not fully restored after the buffing process. Second, tap water was being used for the final rinse, and chloride-containing tap water was accelerating surface attack on the incompletely passivated surface.
REFA Solution
Step 1: REFA Stainless Steel Degreaser
Removes buffing compound, polishing oil, and handling contamination completely. Formulated to be free of ammonia (no stress corrosion risk) and compatible with 304 and 316 grade stainless steel.
Step 2: REFA Passivation Treatment
Dilute nitric acid-based passivation treatment that restores the chromium oxide passive layer after mechanical working and buffing. This step is the critical missing element in the client’s original process — without passivation, the disrupted passive layer from polishing never fully reforms, leaving the surface vulnerable to rapid oxidation.
Step 3: DM Water Final Rinse
Replaces tap water — eliminates chloride ion contamination of the freshly passivated surface.
Results
Surface rejection rate reduced from 9% to under 0.8% within 3 production cycles of the process change.
- Export rejection claims: eliminated in the 8 months following process change
- Middle East distributor: order volume increased by 30% — citing improved and consistent quality
- Passivation test (ASTM A967 copper sulphate test): 100% pass rate vs. 64% previously
- Annual saving from rejection elimination: estimated Rs. 7.2 lakhs
- REFA stainless steel cleaning and passivation process adopted as standard across all production lines
Looking for stainless steel degreasers and passivation chemicals for cutlery and cookware manufacturers?
Contact REFA Chemical Industries Pvt. Ltd. — Greater Noida | Our founder brings 25+ years of industrial chemical expertise to every solution we supply. Call or WhatsApp for free samples and technical consultation.