S-91257A612 5/16"-24 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Superior corrosion resistance with zinc yellow-chromate plating, extending service life in harsh industrial environments.
• High hardness rating (Rockwell C33) provides excellent wear resistance and durability under repetitive loads.
• Precise UNF fine threading with Class 2A fit offers secure, vibration-resistant connections in machinery and equipment.
• Partially threaded design allows for controlled clamping force and easier alignment in assembly operations.
• External hex drive enables quick installation and removal with standard tools, improving maintenance efficiency.
• Compliance with ASME B18.2.1 standards guarantees consistent quality and interchangeability for industrial projects.

Professional Applications & Engineering Value

These Grade 8 hex head screws are engineered to address critical fastening challenges in heavy-duty sectors such as construction, automotive, and machinery manufacturing. The combination of high-strength steel and UNF fine thread design ensures superior load distribution and resistance to loosening under dynamic stresses. The zinc yellow-chromate plating provides a robust barrier against oxidation and chemical exposure, making them ideal for outdoor or corrosive environments. With a partially threaded configuration, they offer optimal grip length for structural joints, reducing the need for additional components and simplifying inventory management. This industrial fastener delivers reliable performance in applications demanding high tensile strength and long-term durability, from assembly lines to equipment repairs.

Specification Summary & Compliance

This 5/16"-24 hex head screw adheres to precise dimensional tolerances, including Class 2A thread fit for consistent engagement and ASME B18.2.1 manufacturing specifications. It is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, ensuring environmental safety and material integrity. The product meets SAE J429 standards for Grade 8 mechanical properties, guaranteeing reliability in industrial use.