Eliminating field corrosion complaints for a Dutch fastener distributor

The situation

A Rotterdam distributor was receiving site complaints about surface rust on installed A4 bolts in coastal and indoor-pool projects. The root cause was inconsistent passivation at the previous supplier, invisible on incoming inspection.

What was done

• 1The requirement was re-specified against a measurable acceptance test before any price was discussed — in this case warranty claims per million bolts installed measured on incoming goods, not on a supplier’s own paperwork.
• 2Process control was changed to hold that measurement: standard at DIN 933 (ISO 4017 equivalent), size at M6 × 30 mm.
• 3Evidence was tied to each lot so the buyer could verify the claim rather than trust it. That is why the programme ran 120 days: the first 6 lots were used to prove stability before volume was released.

Evidence you can ask to see

Neutral salt spray test reports to ASTM B117 per lot, heat-number and mill certificate linkage, buyer warranty claim statistics

These are buyer-side or third-party records, not supplier marketing. Where a document is commercially sensitive we will ask the buyer for permission before sending it, and say so rather than sending a redacted page that proves nothing.

The part involved