STAINLESS STEEL LARGE SERIES FLAT WASHERS 200HV ISO 7093-1

Large Series Flat Washers 200HV ISO 7093-1 — ISO 7093-1 sits at the opposite end of the same 200HV washer family from ISO 7092 - a wider outside diameter than the normal ISO 7089 washer for a given bolt size, specified wherever the joint needs a bigger bearing footprint than the standard series provides. That is typically because the clearance hole is larger than normal, the clamped material is softer or lower-strength than steel, or the design simply calls for extra load spreading to reduce local bearing stress on the surface underneath. It shares the 200HV hardness classification and general form of ISO 7089, but it is a distinct standard with its own outside diameter and thickness table for the large series, rather than simply a bigger version of the same drawing, so sizes should be checked against ISO 7093-1's own tables rather than assumed to scale directly from ISO 7089. It plays a broadly similar role to DIN 9021, another large-diameter washer standard, but the two should not be treated as interchangeable without checking the specific outside diameter and thickness each calls for, since they are governed by separate dimensional tables. Where a connection is genuinely structural - designed and certified to structural steelwork practice - DIN 7989 remains the more directly applicable standard even though ISO 7093-1 also offers a large bearing area. Grade selection follows the same logic as the rest of the ISO 200HV series: A2 (304-equivalent) stainless is the correct default for general, outdoor, and washdown applications, while A4 (316-equivalent) earns its extra cost specifically in coastal, marine, or chemically exposed environments, where a large-diameter A2 washer would otherwise present more surface area for chloride-driven pitting to take hold. To specify correctly, match the bore to the bolt diameter and confirm the joint's clamped material or hole condition genuinely calls for the extra bearing area the large series provides, rather than defaulting to it where the normal series would do.

FAQs
How does ISO 7093-1 compare to DIN 9021?
Both provide a larger-than-standard outside diameter for load spreading, but they are governed by different standards with their own dimensional tables, so the two should not be assumed interchangeable without checking.

When is the large series worth the extra material cost over the normal series?
Specifically where the clamped material is soft, the hole is oversized, or bearing stress is marginal on the normal series; for typical steel-on-steel joints in good condition, the normal series is usually sufficient and more economical.

How do I choose the correct ISO 7093-1 washer?
Match the bore to the bolt diameter and specify the large series where the clamped material or hole condition requires additional load-spreading area beyond the normal series.