S-90474A138 0.344" ID x 1.125" OD ASME Washers

Key Features & Benefits at a Glance

• Enhanced Corrosion Resistance: Black-oxide steel surface treatment provides superior protection against rust and environmental degradation, extending service life in demanding industrial conditions.
• Precise Load Distribution: 1.125" outer diameter and 0.051-0.080" thickness ensure optimal surface coverage, preventing fastener loosening and material damage under vibration or heavy loads.
• Perfect Fit for 5/16" Fasteners: 0.344" inner diameter offers accurate alignment with standard 5/16" screws, reducing installation time and eliminating compatibility issues.
• Exceptional Mechanical Strength: Rockwell B80 hardness rating guarantees reliable performance under high-stress applications without deformation or failure.
• Regulatory Compliance Assurance: Full compliance with RoHS 3 and REACH standards ensures safe usage in regulated industries and global market acceptance.
• Dimensional Consistency: Manufactured to precise inch system specifications for reliable interchangeability and predictable performance in assembly operations.
• Versatile Industrial Application: Suitable for machinery, construction, and automotive applications where corrosion resistance and durability are critical requirements.

Professional Applications & Engineering Value

These 5/16" flat washers with black-oxide steel construction address critical engineering challenges in industrial environments. The black-oxide surface treatment creates a protective barrier that significantly reduces oxidation and corrosion, making them ideal for outdoor equipment, marine applications, and manufacturing facilities with high humidity exposure. The precise dimensional tolerances (0.344" ID x 1.125" OD) ensure perfect compatibility with standard 5/16" screws, eliminating assembly errors and reducing maintenance frequency. With their Rockwell B80 hardness, these washers maintain structural integrity under repetitive loading conditions, preventing surface indentation and maintaining clamping force in vibrating machinery. The combination of corrosion resistance and mechanical durability makes them essential components for automotive assemblies, structural steel connections, and heavy equipment where reliability cannot be compromised.

Specification Summary & Compliance

Manufactured to standard inch system dimensions with 0.344" inner diameter, 1.125" outer diameter, and 0.051-0.080" thickness range. These flat washers are engineered for use with 5/16" screws and feature Rockwell B80 hardness for consistent performance. Full compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations ensures environmental safety and unrestricted use in global industrial markets. The black-oxide steel construction meets industry standards for corrosion protection in demanding applications.