S-98040A110 21 mm ID x 35 mm OD Oversized Washers

Key Features & Benefits at a Glance

• Enhanced corrosion resistance from black-oxide steel surface treatment, extending service life in harsh industrial environments
• Superior load distribution with precise 21mm ID and 35mm OD dimensions, preventing surface damage to connected components
• Exceptional hardness rating of Rockwell 15N80 ensures minimal deformation under heavy mechanical stress
• Perfect compatibility with M20 metric screws, providing reliable fastening in heavy-duty assemblies
• Regulatory compliance assurance with RoHS 3 and REACH standards, meeting global environmental and safety requirements
• Optimized thickness range (4.5-5.4mm) delivers consistent performance while accommodating manufacturing tolerances
• Durable steel construction maintains structural integrity through repeated installation and removal cycles

Professional Applications & Engineering Value

This M20 flat washer engineered from black-oxide steel addresses critical industrial fastening challenges where corrosion resistance and load-bearing capacity are paramount. The metric dimensions (21mm ID × 35mm OD) create an optimal bearing surface that prevents bolt head embedding and distributes clamping forces evenly across joined materials. The Rockwell 15N80 hardness ensures the washer maintains its form under extreme pressure, making it ideal for heavy machinery, structural steel connections, and automotive assemblies where vibration resistance is essential. The black-oxide finish provides a protective barrier against moisture and chemicals without significantly altering dimensional tolerances, while the compliance with international standards guarantees suitability for regulated industries including manufacturing, construction, and transportation equipment.

Specification Summary & Compliance

Precision-engineered to metric system standards with 21mm internal diameter and 35mm outer diameter, this flat washer features a thickness range of 4.5-5.4mm for M20 screw applications. Manufactured from black-oxide steel with Rockwell 15N80 hardness rating, the product maintains dimensional stability under load. Compliance includes RoHS 3 (2015/863/EU) with exemption 6(a) for lead as an alloying element in steel and full adherence to REACH (EC 1907/2006) regulations regarding substance restrictions.