How to choose the right material and finish for an ISO 7090 chamfered washer
The material and finish of an ISO 7090 chamfered plain washer must match the operating environment and the fastener assembly. Start with the corrosion risk, temperature, and mechanical load, then confirm the standard dimensions and hardness class.
Material options verified from TaurusFix supply range
TaurusFix supplies ISO 7090 chamfered washers in two material groups:
- Carbon steel – suitable for dry, indoor, or low-corrosion environments when paired with a protective finish.
- Stainless steel – preferred for wet, washdown, marine, or mildly corrosive atmospheres. Stainless washers also avoid galvanic corrosion when used with stainless bolts and nuts.
No specific stainless steel grade (e.g., A2, A4) is listed in the supplied product data. Confirm the exact grade against the project specification or request a material certificate when ordering.
Finish selection for carbon steel washers
Carbon steel ISO 7090 washers typically require a surface finish to resist rust. Common industrial finishes (not verified from TaurusFix data) include:
- Zinc plating (electro‑galvanised) – economical, suitable for indoor use; avoid outdoors unless top‑coated.
- Hot‑dip galvanising – thick zinc layer for outdoor structural applications; may require oversize tapping on nuts due to coating thickness.
- Mechanical zinc (sherardising) – uniform coverage, no hydrogen embrittlement risk; good for high‑strength fasteners.
- Dacromet® / Geomet® – high corrosion resistance without hydrogen risk; often specified in automotive and wind energy.
Important: The TaurusFix product summary does not list specific finishes. When requesting a quotation, state the required finish and, if applicable, the corrosion‑resistance hours (e.g., 720 h salt spray to ISO 9227).
Hardness class and mechanical compatibility
ISO 7090 defines hardness classes that must be matched to the bolt/nut assembly. Typical guidance (not a TaurusFix measured value):
- 100 HV – for bolts up to property class 5.6.
- 200 HV – for bolts up to property class 8.8.
- 300 HV – for bolts up to property class 10.9.
Using a washer that is too soft can lead to embedding and loss of preload. Verify the hardness class on the TaurusFix technical data sheet (TDS) or drawing before ordering.
Dimensional checkpoints for quotation
ISO 7090 washers are chamfered on the outer diameter to reduce edge stress. When preparing a request, confirm:
- Nominal bolt size (M5–M52 from TaurusFix range).
- Inside diameter (d1) tolerance – standard or close‑fit.
- Outside diameter (d2) and thickness (h) per ISO 7090 tables.
- Chamfer angle and width – usually 30°–45°, but check the standard for the specific size.
Always refer to the current ISO 7090 standard or the TaurusFix TDS for exact dimensions.
Quotation checklist for ISO 7090 chamfered washers
Use this checklist to avoid rework when contacting TaurusFix:
- Standard: ISO 7090 (confirm revision).
- Size: M__ (e.g., M12).
- Material: Carbon steel or stainless steel (specify grade if known).
- Finish: Plain, zinc, HDG, or other (state required corrosion resistance).
- Hardness class: 100 HV, 200 HV, or 300 HV (or state bolt property class).
- Quantity: Note MOQ 1000–5000 pcs; smaller batches may be possible—ask.
- Certification: Request material certificate or inspection document if needed.
Next step
Review the ISO 7090 technical data sheet for verified dimensions and hardness options, then submit a quotation request with the checklist above.
