S-91236A558 1/4"-20 x 4" ASME B18.2.1, ASTM A307 Low-Strength Steel Hex Head Screws
Low-Strength 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
- Superior corrosion resistance with zinc plating, extending service life in demanding environments
- High tensile strength of 60,000 psi ensures reliable performance under heavy loads and vibrations
- Rockwell B69 hardness provides excellent durability and resistance to wear and deformation
- UNC coarse threading offers faster assembly and reduced cross-threading risk compared to fine threads
- Class 2A thread fit guarantees consistent, precise engagement for secure fastening in industrial applications
- External hex drive design allows for high-torque installation with common tools, improving efficiency
- Partial threading provides unthreaded shank for enhanced shear strength and alignment in structural uses
Professional Applications & Engineering Value
This 1/4"-20 x 4" steel hex head screw is engineered to address critical challenges in industrial assembly, such as vibration loosening and environmental corrosion. The zinc plating acts as a sacrificial layer, significantly reducing rust formation in humid or outdoor settings, while the UNC coarse thread ensures quick, reliable fastening even in materials with varying densities. Its partial threading design concentrates stress on the threaded portion, minimizing shank fatigue and improving joint integrity in machinery, construction, and automotive frameworks. By combining 60,000 psi tensile strength with a Rockwell B69 hardness rating, it withstands repetitive loads without stripping or failure, making it ideal for heavy-duty applications where safety and longevity are paramount.
Specification Summary & Compliance
This screw adheres to ASME B18.2.1 and ASTM A307 specifications, ensuring dimensional accuracy with a Class 2A thread fit for consistent performance. It features a 1/4"-20 UNC coarse thread, right-hand direction, and a 4" length with a minimum thread length of 3/4". The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, guaranteeing it is free from hazardous substances for safe use in global industrial markets.
