S-91257A595 5/16"-18 x 3" 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 zinc yellow-chromate plating extends service life in harsh industrial environments, minimizing maintenance needs.
- High hardness rating (Rockwell C33) provides excellent wear resistance and durability under repetitive loads.
- Precise Class 2A thread fit guarantees smooth installation and secure fastening with standard UNC coarse threads.
- Partially threaded design allows for optimal clamping force distribution, ideal for applications requiring specific grip lengths.
- External hex drive compatibility enables quick installation and removal with common tools, improving assembly efficiency.
- Compliance with industry standards including ASME B18.2.1 and SAE J429 ensures consistent quality and interchangeability.
Professional Applications & Engineering Value
This Grade 8 hex head screw delivers exceptional engineering value in demanding industrial settings where fastener reliability is critical. The combination of high-strength steel material and zinc yellow-chromate plating provides robust protection against corrosion and mechanical stress, making it ideal for heavy machinery, construction equipment, and automotive assemblies. The UNC coarse thread design ensures rapid installation and superior resistance to vibration loosening, while the partially threaded configuration offers precise clamping control in structural applications. Engineered to meet rigorous ASME B18.2.1 and SAE J429 specifications, this fastener provides dependable performance in environments where safety and durability are paramount.
Specification Summary & Compliance
This 5/16"-18 x 3" hex head screw features Class 2A thread fit tolerances with UNC coarse threading and partial threading up to 7/8" minimum length. Manufactured to Grade 8 standards with 150,000 psi tensile strength and Rockwell C33 hardness. Compliant with ASME B18.2.1 and SAE J429 specifications, and meets environmental regulations including RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) compliance.
