S-91128A311 9 mm ID Square Washers

Key Features & Benefits at a Glance

• Enhanced corrosion resistance with black-oxide steel coating, extending service life in humid or harsh industrial environments
• Superior load distribution due to the 50mm square design, preventing surface damage and maintaining joint integrity under heavy loads
• Precise M6 screw compatibility with 9mm inner diameter, ensuring secure fit and reducing installation errors
• Exceptional mechanical strength from Rockwell 15N80 hardness, resisting deformation under high-pressure applications
• Regulatory compliance assurance with RoHS 3 and REACH standards, meeting strict environmental and safety requirements for industrial use
• Optimized thickness of 6.0mm for reliable spacing and vibration dampening in heavy machinery assemblies
• Durable material construction using steel, providing long-term reliability in demanding fastening scenarios

Professional Applications & Engineering Value

This M6 square washer is engineered to address common industrial challenges such as fastener loosening, surface indentation, and corrosion-induced failure. The black-oxide steel material offers a protective layer that significantly reduces oxidation, making it ideal for outdoor equipment, automotive frames, and machinery exposed to moisture. Its square shape and substantial 50mm width distribute clamping force over a larger area, preventing damage to soft materials and ensuring stable connections in structural applications. With a Rockwell 15N80 hardness, it maintains dimensional stability under repetitive stress, while the precise 9mm ID aligns perfectly with M6 screws, streamlining assembly in production lines. These features make it a trusted component for engineers seeking corrosion-resistant, high-strength fastening solutions in construction, manufacturing, and heavy-duty industrial systems.

Specification Summary & Compliance

This washer adheres to metric system standards with an inner diameter of 9mm, thickness of 6.0mm, and width of 50mm, designed for M6 screw sizes. It meets RoHS 3 (2015/863/EU) compliance under exemption 6(a) for lead as an alloying element in steel and is REACH (EC 1907/2006) compliant as of January 17, 2023, covering 233 SVHCs. The black-oxide steel construction and Rockwell 15N80 hardness ensure consistent performance in industrial settings, supporting reliable fastening without compromising regulatory requirements.