STAINLESS STEEL CHAMFERED FLAT WASHERS 200HV ISO 7090

Chamfered Flat Washers 200HV ISO 7090 — ISO 7090 shares its bore, outside diameter, thickness range, and 200HV hardness classification with ISO 7089 - the only real difference is a small bevel machined into one face at the outer edge. That chamfer exists mainly for a cleaner finish and to seat properly against a filleted or radiused bearing face, such as under a bolt head or nut where the transition into the shank is not perfectly square; without it, the washer's inner edge can foul on that radius and rock rather than sitting flat. It also removes a sharp outer edge, which is a minor but genuine benefit during handling and assembly. The chamfer has minimal effect on load-bearing performance in itself, since it only removes a small amount of material at the outer edge - the hardness class and overall dimensions still govern how the washer performs under load far more than the edge finish does. That makes ISO 7090 the natural choice specifically where the joint geometry benefits from the chamfer - filleted bolt heads, radiused shoulders, or where a drawing simply specifies the chamfered form - while the plain ISO 7089 remains the more general default elsewhere. As with its unchamfered sibling, grade selection is where the meaningful decision sits: A2 (304-equivalent) stainless is the correct default for the large majority of general, outdoor, and washdown applications, while A4 (316-equivalent) is worth specifying only where the joint faces genuine chloride or chemical exposure - coastal structures, marine equipment, or process plant handling aggressive cleaning agents - since that is where A2's corrosion resistance eventually runs out and A4's molybdenum content earns its higher price. To choose correctly, match the bore to the bolt diameter, confirm the drawing calls for a chamfered edge rather than defaulting to it automatically, and check that 200HV hardness is adequate for the fastener grade and preload involved.

FAQs
Does the chamfer face a particular direction when fitted?
Yes - the chamfered face should sit against the bolt head or nut radius it is designed to clear, with the flat face bearing against the clamped component.

Does the chamfer affect load-bearing performance?
It has minimal effect since it removes only a small amount of material at the outer edge; the hardness class and overall dimensions govern performance more than the chamfer itself.

How does ISO 7090 differ from ISO 7089?
The two share the same bore, outside diameter, and thickness ranges; the only functional difference is that ISO 7090 has the chamfered edge, while ISO 7089 does not.