S-91455A340 4.3 mm ID x 9 mm OD DIN 125; ISO 7089 General Purpose Washers

Key Features & Benefits at a Glance

• Enhanced Corrosion Resistance: Zinc plating provides a protective barrier, extending service life in humid or industrial environments.
• Superior Load Distribution: Flat design with 9mm OD and 4.3mm ID ensures even pressure distribution, preventing surface damage and loosening under M4 screw loads.
• Consistent Mechanical Performance: Rockwell B91 hardness offers reliable strength and deformation resistance for repeated assembly cycles.
• Guaranteed Dimensional Precision: Manufactured to DIN 125 and ISO 7089 standards, ensuring perfect fit and interchangeability in metric fastener systems.
• Strict Environmental Compliance: Meets RoHS 3 and REACH regulations, making it safe for global supply chains and sensitive applications.
• Optimized Thickness Control: 0.7-0.9mm thickness range allows for precise gap filling and vibration dampening without adding bulk.

Professional Applications & Engineering Value

This M4 zinc plated steel flat washer is engineered to address common industrial fastening challenges, such as galvanic corrosion, joint fatigue, and assembly inaccuracies. The zinc plating acts as a sacrificial layer, significantly reducing rust formation in mechanical assemblies exposed to moisture or chemicals. Its compliance with DIN 125 and ISO 7089 standards ensures that it delivers consistent performance in metric fastener applications, from automotive subassemblies to electrical enclosures. The precise inner and outer diameters (4.3mm ID, 9mm OD) prevent misalignment and distribute clamp load effectively, minimizing stress concentrations that lead to material failure. By integrating this flat washer into your designs, you achieve reliable, long-lasting connections that meet stringent industry specifications.

Specification Summary & Compliance

This washer features a 4.3 mm inner diameter, 9 mm outer diameter, and 0.7-0.9 mm thickness, manufactured to Class A dimensional tolerances per DIN 125 and ISO 7089 standards. It is made from zinc plated steel with a Rockwell B91 hardness for consistent mechanical properties. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring it is free from hazardous substances and suitable for industrial and export markets.