Jian Chen Mould 
Jason Metal Products 
Citric or nitric passivation, batch documentation, copper sulphate test included
Part no.: NV-SUR-8010
| Standard | ASTM A967 (Nitric 1, Nitric 2, Citric 1–3) |
|---|---|
| Materials | 300-series and 400-series stainless, precipitation hardening grades |
| Bath temperature | 20 – 60 °C depending on method |
| Immersion time | 20 – 60 minutes, logged per batch |
| Verification | Copper sulphate test; 24 h humidity test optional |
| Documentation | Batch certificate with method, parameters and result |
| Max part size | 1,200 × 800 × 600 mm |
Passivation removes free iron and exogenous contamination from machined stainless surfaces, restoring the chromium oxide layer that actually provides the corrosion resistance. Machining, tumbling and handling all embed iron; without passivation a 316 part can rust in a humid warehouse.
Citric acid passivation (ASTM A967 Nitric 1 / Citric 2 options) with bath concentration, temperature and immersion time logged per batch. Verification is by copper sulphate test and, where specified, a 24-hour humidity test.
Each batch ships with a certificate stating the method, the bath parameters, the test performed and the result.
No. Passivation removes surface contamination at the atomic scale and typically changes dimensions by less than 0.0005 mm, far below any drawing tolerance.
Citric is safer to handle and dispose of and is now accepted by most specifications including ASTM A967. Nitric is still preferable for 400-series and for parts that were heat treated or heavily machined, where more aggressive iron removal helps.
Send drawings, a part number or a description of the component you need. We reply with a quotation, lead time and tooling assessment — usually within one business day.
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