S-91251A583 5/16"-18 x 1" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 170,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance from the black-oxide finish extends service life in harsh industrial environments, minimizing maintenance needs.
• Precision Class 3A thread fit provides tight tolerances for secure fastening and vibration resistance in critical assemblies.
• High hardness rating (Rockwell C37) offers excellent wear resistance, maintaining thread integrity through repeated use.
• Standard hex drive compatibility with 1/4" tools allows for easy installation and removal with common industrial equipment.
• Full threading design enables consistent engagement along the entire length, providing uniform clamping force.
• Regulatory compliance with ASTM A574, RoHS 3, and REACH standards ensures environmental responsibility and material quality consistency.

Professional Applications & Engineering Value

Engineered for demanding industrial applications, this 5/16"-18 UNC socket head cap screw delivers critical performance advantages where reliability is non-negotiable. The black-oxide alloy steel construction provides superior protection against corrosion while maintaining the high tensile strength required for heavy machinery, automotive assemblies, and precision equipment. The Class 3A thread fit ensures minimal backlash and superior vibration resistance in dynamic loading conditions, while the coarse thread pattern facilitates quicker assembly in production environments. These socket head cap screws are particularly valuable in applications requiring flush mounting and high clamping forces, such as jigs, fixtures, and structural frameworks where access space is limited but performance cannot be compromised.

Specification Summary & Compliance

This fastener features 5/16"-18 UNC coarse threads with Class 3A fit for precision engagement, manufactured from alloy steel with black-oxide surface treatment. The 1" length provides versatile application coverage while maintaining dimensional consistency. Compliance includes ASTM A574 specification for alloy steel socket head cap screws, ensuring material and manufacturing consistency. Environmental compliance is verified through RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) adherence, confirming restricted substance compliance for global industrial use.