S-91251A404 5/8"-18 x 2 1/2" ASTM A574 Alloy Steel Socket Head Screws
Alloy Steel Socket 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
- Superior corrosion resistance with black-oxide coating, extending service life in demanding industrial environments
- Exceptional tensile strength of 170,000 psi prevents fastener failure under extreme loads
- Precision Class 3A thread fit ensures secure, vibration-resistant connections in critical assemblies
- Fine UNRF threading provides enhanced clamping force and superior resistance to loosening
- High hardness rating (Rockwell C37) maintains structural integrity and thread form under repeated use
- Optimized partial threading allows precise engagement control while maximizing unthreaded shank strength
- Standard hex socket drive enables high-torque installation with common industrial tools
Professional Applications & Engineering Value
Engineered for heavy-duty industrial applications, this black-oxide alloy steel socket head cap screw addresses critical fastening challenges in machinery, automotive, and construction equipment. The UNRF fine thread configuration delivers superior vibration resistance compared to coarse threads, maintaining clamp load in dynamic environments. With 170,000 psi tensile strength and Rockwell C37 hardness, this fastener withstands extreme mechanical stresses while the black-oxide surface treatment provides essential corrosion protection. The partially threaded design offers optimal strength-to-weight ratio, making it ideal for precision assemblies requiring specific engagement lengths. These socket head cap screws are particularly valuable in applications where space constraints demand compact, high-strength fastening solutions.
Specification Summary & Compliance
This fastener maintains Class 3A thread fit precision with 5/8"-18 UNRF fine threads and 2 1/2" length. Manufactured to ASTM A574 specification for socket head cap screws, ensuring consistent quality and performance. Fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, making it suitable for global industrial applications requiring restricted substance compliance.
