S-91257A640 3/8"-16 x 4" 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 load-bearing capacity with 150,000 psi tensile strength, ideal for high-stress industrial applications.
- Superior corrosion resistance provided by zinc yellow-chromate plating, extending service life in harsh environments.
- Reliable fastening performance due to Grade 8 classification and Rockwell C33 hardness, ensuring minimal wear and deformation.
- Easy installation and removal with external hex drive and coarse UNC threads, reducing assembly time.
- Optimized thread engagement through Class 2A thread fit and partial threading, preventing loosening under vibration.
- Heavy-duty construction from high-strength steel, suitable for demanding machinery and equipment.
- Compliance with industry standards including ASME B18.2.1 and SAE J429, guaranteeing consistent quality and safety.
Professional Applications & Engineering Value
Engineered for rigorous industrial use, this Grade 8 hex head screw delivers robust performance in heavy machinery, structural assemblies, and automotive systems. The steel material combined with zinc yellow-chromate plating effectively combats rust and chemical exposure, reducing maintenance costs in corrosive settings. Its partial threading and coarse UNC thread design enhance grip in soft materials and resist vibration-induced loosening, while the external hex drive allows for high-torque application with standard tools. Ideal for high tensile strength requirements, it ensures long-term reliability in construction, manufacturing, and equipment repair, minimizing downtime and replacement frequency.
Specification Summary & Compliance
This fastener adheres to Class 2A thread fit tolerances and UNC thread standards, ensuring precise compatibility. Manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, it meets rigorous engineering criteria. Additionally, it is RoHS 3 (2015/863/EU) Compliant and REACH (EC 1907/2006) Compliant, supporting environmental and safety regulations in global supply chains.
