Why Finish Selection Matters
Surface finish affects corrosion resistance, appearance, assembly behavior and inspection requirements. For hardened washers, finish selection also needs attention to hydrogen embrittlement risk. DJ WASHERS confirms coating by standard, size, hardness target, application and export packing requirement during RFQ.
| Finish | Typical Use | RFQ Notes |
|---|---|---|
| Plain / bright | Indoor or temporary protected use | Confirm oiling, packing and rust-prevention requirement. |
| Black oxide | Dark appearance and light protection | Often paired with oiling or controlled packing. |
| Electro-zinc plating | General machinery and warehouse stock | Specify color, thickness expectation and packing. |
| Hot-dip galvanizing | Outdoor and construction environments | Check standard, washer size and coating fit before order. |
| Zinc-aluminum / Dacromet type coating | Structural or vibration-related washer RFQs | Useful where corrosion and hardened-part risk must be reviewed. |
| Mechanical zinc | Hardened parts where hydrogen embrittlement risk is a concern | Confirm feasibility by washer standard and size. |
Hydrogen Embrittlement Note
For hardened structural washers, spring lock washers and wedge-lock washer pairs, buyers should not choose coating only by appearance. The RFQ should state hardness target, standard and service environment so coating can be reviewed safely.
Finish By Product Type
- Flat washers: plain, black oxide, zinc, hot-dip galvanizing and zinc-aluminum options by RFQ.
- Structural washers: finish must match EN 14399-6, DIN 6916, ASTM F436 or drawing requirements.
- DIN 25201 wedge-lock washers: washer pairs often require finish review before bulk order.
- Custom stamping parts: geometry and assembly surfaces affect coating choice.
What To Include In The RFQ
Send the standard, size, material, hardness target, expected finish, corrosion requirement, quantity and packing method. If the finish is tied to a project specification, attach that specification or summarize the requirement clearly.