S-90377A137 0.156" ID x 0.438" OD Oversized Washers

Key Features & Benefits at a Glance

• Superior corrosion resistance with Black-Oxide 18-8 Stainless Steel construction, ideal for humid or chemically aggressive environments
• Enhanced load distribution with precise 0.156" ID and 0.438" OD dimensions, preventing surface damage and loosening under vibration
• Optimized durability thanks to Rockwell B68 hardness, maintaining structural integrity under repeated stress
• Reliable fit for No. 6 screws, ensuring secure fastening in assembly lines and machinery
• Consistent performance with controlled thickness range (0.020-0.040"), providing uniform pressure across applications
• Environmental compliance meeting RoHS 3 and REACH standards, safe for regulated industries
• Long-term cost efficiency by reducing replacement frequency in heavy-duty industrial settings

Professional Applications & Engineering Value

This Black-Oxide 18-8 Stainless Steel flat washer is engineered to address common industrial challenges like fastener corrosion, vibration-induced loosening, and material fatigue. The Black-Oxide surface treatment significantly enhances corrosion resistance, making it suitable for outdoor equipment, marine hardware, and chemical processing plants where moisture and corrosive agents are prevalent. With a Rockwell B68 hardness, it withstands high clamping forces without deforming, ensuring reliable performance in heavy-duty washers applications such as automotive assemblies, machinery frames, and electrical enclosures. The precise 0.156" ID and 0.438" OD dimensions provide optimal load distribution, preventing bolt head embedment and surface damage on softer materials. As a RoHS 3 and REACH compliant component, it meets stringent environmental regulations, offering peace of mind for OEMs and maintenance teams in regulated sectors.

Specification Summary & Compliance

This flat washer features a 0.156" inner diameter (ID) and 0.438" outer diameter (OD) with a thickness range of 0.020-0.040", designed for No. 6 screw size applications. Manufactured from 18-8 Stainless Steel with a Black-Oxide finish, it achieves a Rockwell B68 hardness for consistent mechanical properties. The product complies with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) standards, ensuring adherence to environmental and safety regulations for industrial use.