S-91116A340 4.3 mm ID x 12 mm OD DIN 9021 Oversized Washers

Key Features & Benefits at a Glance

• Corrosion-resistant performance with Black-Oxide 18-8 Stainless Steel, ideal for harsh industrial environments and extending service life.
• Superior load distribution due to precise 4.3mm ID and 12mm OD dimensions, reducing stress on M4 fasteners and assemblies.
• Enhanced vibration resistance to maintain joint integrity and prevent loosening in dynamic applications.
• Reliable hardness and durability with Rockwell B68 rating, ensuring consistent performance under mechanical stress.
• Compliance with DIN 9021 standards for guaranteed dimensional accuracy and interchangeability in metric systems.
• Environmental and safety adherence through RoHS 3 and REACH compliance, meeting strict regulatory requirements.
• Broad industrial compatibility for use with M4 screws in machinery, electronics, and automotive sectors.

Professional Applications & Engineering Value

This M4 metric flat washer is engineered to address common industrial challenges such as corrosion, vibration-induced failure, and uneven load distribution. Made from Black-Oxide 18-8 Stainless Steel, it provides excellent resistance to rust and oxidation, making it suitable for outdoor, marine, or chemically exposed settings. The DIN 9021 specification ensures tight tolerances and a flat profile, which helps prevent surface damage and distributes clamping force evenly across M4 screw connections. This reduces the risk of fastener fatigue and assembly failure in high-stress applications like automotive components, electrical enclosures, and precision machinery. By combining material strength with precise geometry, these washers deliver long-term reliability and minimize maintenance needs in demanding industrial environments.

Specification Summary & Compliance

This washer features an inner diameter of 4.3 mm, outer diameter of 12 mm, and thickness of 0.9–1.1 mm, designed for M4 screw size with standard metric dimensions per DIN 9021. It meets hardness requirements with a Rockwell B68 rating and complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material quality for global industrial use.