S-91257A116 5/16"-18 x 4 3/4" 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 tensile strength of 150,000 psi ensures reliable performance in high-stress industrial applications, reducing the risk of fastener failure.
- Superior corrosion resistance with zinc yellow-chromate plating extends service life in harsh 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 assembly and secure fastening, improving installation efficiency.
- Coarse UNC threading offers quick engagement and reduced cross-threading risks in demanding conditions.
- Partial threading design allows for optimal clamping force distribution, enhancing joint stability in structural applications.
- Compliance with ASME B18.2.1/SAE J429 standards ensures consistent quality and interoperability in regulated industries.
Professional Applications & Engineering Value
Engineered for heavy-duty scenarios, this Grade 8 hex head screw combines high tensile strength and Rockwell C33 hardness to withstand extreme mechanical stresses in construction, machinery assembly, and automotive frameworks. The zinc yellow-chromate plating effectively counters corrosion in outdoor or humid settings, while the coarse UNC thread and Class 2A fit facilitate rapid installation with minimal tool wear. Its partial threading concentrates clamping force near the head, preventing joint loosening in vibrating environments. Ideal for securing structural components, this screw addresses common issues like fatigue and environmental degradation, delivering long-term reliability in industrial fastening applications.
Specification Summary & Compliance
This screw adheres to Class 2A thread fit tolerances and UNC coarse thread standards, with a thread size of 5/16"-18 and a minimum thread length of 7/8". Manufactured in compliance with ASME B18.2.1 and SAE J429 specifications, it meets rigorous industry requirements for dimensional accuracy and performance. The product conforms to common regulatory guidelines, ensuring suitability for professional use in sectors demanding high-strength steel fasteners.
