S-91257A804 5/8"-11 x 2 1/2" ASME B18.2.1, SAE J429 High-Strength Grade 8 Steel Hex Head Screws
High-Strength Grade 8 Steel Hex Head Screws
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Basic Information
Head Parameters
Dimensions
Thread Parameters
Tip & Drive Parameters
Material & Strength
Temperature & Environment
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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 from the zinc yellow-chromate plating extends service life in harsh or outdoor environments.
- High hardness rating (Rockwell C33) provides excellent wear resistance and maintains thread integrity under heavy loads.
- Coarse UNC threading and Class 2A fit allow for faster assembly and easier alignment, improving installation efficiency.
- Partially threaded design offers optimal clamping force on joined materials, preventing loosening in vibrating machinery.
- External hex drive and hex head enable high torque application with standard tools, ensuring secure fastening in tight spaces.
- Compliance with industry standards (ASME B18.2.1, SAE J429) guarantees consistent quality and interchangeability in professional settings.
Professional Applications & Engineering Value
This Grade 8 hex head screw is engineered for demanding industrial applications where high tensile strength and durability are critical. The steel material and Rockwell C33 hardness provide robust resistance to shear and fatigue, making it ideal for heavy machinery, construction equipment, and automotive assemblies. The zinc yellow-chromate plating offers superior protection against corrosion, extending the fastener's lifespan in exposed or humid conditions. With its coarse UNC thread and partial threading, it ensures rapid installation and secure clamping in structural joints, reducing maintenance downtime. This screw meets rigorous ASME and SAE standards, delivering reliable performance in B2B procurement for OEMs and MRO operations.
Specification Summary & Compliance
This fastener adheres to precise dimensional tolerances, including a Class 2A thread fit for consistent engagement and UNC coarse thread specifications. It conforms to ASME B18.2.1 and SAE J429 manufacturing standards, ensuring interoperability and quality. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, supporting environmental and safety requirements in global supply chains.
