ISO 7090:2000 PDF

This International Standard specifies the characteristics of normal-series, product-grade-A plain washers chamfered at the outside diameter, in the 200 HV and 300 HV hardness classes and of nominal sizes (nominal thread diameters) ranging from 5 mm to 64 mm inclusive.

Washers of hardness class 200 HV are suitable for

• bolts and screws of product grades A and B in property classes up to and including 8.8;
• nuts of product grades A and B in property classes up to and including 8;
• bolts, screws and nuts of stainless steel of similar chemical composition;
• case-hardened thread rolling screws.

Washers of hardness class 300 HV are suitable for

• bolts and screws of product grades A and B in property classes up to and including 10.9;
• nuts of product grades A and B in property classes up to and including 10.

If dimensions other than those listed in this International Standard are required, they should be selected from those given in ISO 887.

When soft material pieces are clamped, or large clearance holes in the workpiece are used, the user should check the technical suitability of this type of washer.