DIN 7989-2 Washers for Steel Structures

DIN 7989-2 specifies turned flat washers of product grade A for structural steelwork. These washers are intended for bolted steel connections and are used beneath compatible structural bolts, screws, or nuts to provide a defined bearing surface between the fastener assembly and the connected steel member. The standard specifies metric sizes from M10 through M30, with an 8 mm nominal thickness across the size range.

The most distinctive feature of DIN 7989-2 is its product grade A classification and turned manufacturing form. Unlike a generic thick flat washer, the washer dimensions are controlled according to the requirements for product grade A, including defined dimensional tolerances, thickness variation, and flatness requirements. The standard specifies a hardness class of 100 HV, with Vickers hardness HV 10 in the range of 100 to 250.

The turned construction is particularly relevant to the dimensional definition of the product. The standard establishes controlled hole and outside-diameter dimensions for each nominal thread size. For example, the M24 version has an inside diameter range of 26 to 26.52 mm, an outside diameter range of 43 to 44 mm, and a nominal thickness of 8 mm. This dimensional control gives the washer a clearly defined geometry for structural fastening assemblies.

DIN 7989-2 washers are commonly described as washers for steel structures, structural flat washers, or turned flat washers for steel construction. Their primary application is structural steelwork and other bolted steel assemblies where the specified product grade, washer dimensions, and mechanical properties are required.

One important characteristic of DIN 7989-2 is its position within the DIN 7989 series: Part 2 specifies product grade A, while DIN 7989-1 covers product grade C. The distinction is significant because product grade A provides tighter dimensional requirements and a different manufacturing definition. This makes DIN 7989-2 more than simply another designation for a thick structural washer; its product grade and dimensional requirements form part of the product identity.