Description
Plain Washer M6 A4 Stainless Steel ISO 7089 — BOLTON SKU 60104.
About the Plain Washer M6 A4 Stainless Steel ISO
This Plain Washer M6 A4 Stainless Steel item is a normal-series flat washer manufactured to ISO 7089, the international standard for plain washers of product grade A with hardness class 200 HV. For the M6 size, ISO 7089 defines a 6.4 mm clearance hole, 12 mm outside diameter and 1.6 mm nominal thickness, giving a bearing surface roughly twice the fastener diameter to spread clamping load into the joint face. The washer distributes load under an M6 bolt head or nut, protects softer joint surfaces from marking as the fastener is torqued, and bridges slightly oversized clearance holes. It is made of A4 austenitic stainless steel — the acid-resistant, molybdenum-alloyed grade in the 316 family — which offers higher resistance to chlorides and corrosive media than A2, making it the usual specification for marine, coastal and chemically exposed assemblies.
Key specifications
| Standard | ISO 7089 (plain washers, normal series, hardness 200 HV) |
|---|---|
| Nominal size | M6 |
| Inside diameter | 6.4 mm |
| Outside diameter | 12 mm |
| Thickness | 1.6 mm |
| Material | A4 austenitic stainless steel (316 type) |
Typical applications
A4 flat washers of this size are fitted under M6 bolt heads and nuts wherever the joint faces need protection and the environment is corrosive — deck and exterior hardware, coastal and offshore installations, wash-down equipment and chemically exposed plant. In mixed-material joints they also help isolate the bearing face from galling and surface damage during torquing.
Supplied by BOLTON Technical Equipment Supplies against request for quotation. Add this item to your RFQ basket to request pricing, lead time and documentation requirements (e.g. CoC, datasheets or test reports where applicable).
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