STAINLESS STEEL FLAT WASHERS 200HV ISO 7089

Flat Washers 200HV ISO 7089 — ISO 7089 is the current international reference for the everyday metric flat washer - the direct replacement for DIN 125B in the unchamfered form - and its 200HV designation refers to the Vickers hardness the washer material is guaranteed to meet, a minimum level intended to ensure it can withstand normal bolted-joint bearing pressure without excessive deformation. That hardness class is what separates it from the 300HV washers used under higher property-class fasteners, and it is the detail worth checking whenever a joint is being tightened to a higher preload than typical general assembly, since an under-hardened washer can crush or dish under load rather than doing its job of spreading it evenly. As the standard-series washer, ISO 7089 is the default specification for general mechanical, structural, and engineering assembly across most industries - the washer to reach for unless something about the joint (a chamfer requirement, extra bearing area, or a smaller footprint) points to one of its siblings instead. ISO 7090 is functionally identical but chamfered on one face, specified wherever the washer needs to sit flush against a filleted or radiused bearing surface; ISO 7092 trades some bearing area for a smaller outside diameter where clearance is tight; and ISO 7093-1 goes the other way, offering a wider bearing footprint for soft materials or oversized holes. Grade selection is where real cost decisions get made: A2 (304-equivalent) stainless covers the overwhelming majority of general indoor, outdoor, and washdown applications without issue, and it is the sensible default. A4 (316-equivalent) is worth the extra spend specifically where the joint faces sustained chloride exposure - coastal and marine equipment, de-icing salt, swimming pool plant, or chemical processing - since A2 will eventually pit in those conditions while A4's molybdenum content resists it. Choosing correctly means matching the bore to the bolt diameter, confirming 200HV hardness suits the joint's preload, and deciding whether a chamfered or unchamfered edge is actually required.

FAQs
When would 300HV hardness be needed instead of 200HV?
Where the joint is tightened to a higher preload than standard property-class bolts generate, typically alongside high-tensile fastener grades; check the fastener grade against the washer's rated hardness before assuming 200HV is adequate.

How does ISO 7089 differ from ISO 7090?
ISO 7089 is unchamfered on the outer edge, while ISO 7090 has a chamfer. Functionally they perform the same role; the difference is primarily in edge finish.

Is ISO 7089 the same as DIN 125?
ISO 7089 is dimensionally equivalent to DIN 125B (unchamfered) and has effectively replaced it as the current international reference, though DIN 125 is still commonly quoted commercially.