S-91771A578 5/16"-18 x 1/2" ASME B18.6.3 Stainless Steel Phillips Flat Head Screws
Stainless Steel Phillips Flat 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 passivated 18-8 stainless steel construction, ensuring long-term reliability in harsh industrial environments
- Exceptional mechanical strength with 80,000 psi tensile strength and Rockwell B80 hardness for demanding applications
- Precise flush mounting featuring undercut flat head profile and 82° countersink angle for seamless surface integration
- Optimized drive engagement with Phillips No. 4 drive design providing secure installation and reduced cam-out risk
- Reliable thread performance through Class 2A thread fit and UNC coarse threading for vibration resistance
- Full-length threading ensures maximum grip strength and uniform load distribution across the entire fastener length
- Regulatory compliance meeting ASME B18.6.3 specifications and environmental standards including RoHS 3 and REACH
Professional Applications & Engineering Value
These 5/16"-18 UNC flat head screws deliver critical engineering solutions where surface flushness and corrosion resistance are paramount. The passivated 18-8 stainless steel construction provides exceptional protection against oxidation and chemical exposure, making them ideal for marine equipment, food processing machinery, and outdoor industrial applications. The undercut flat head profile with 82° countersink angle ensures perfect flush mounting while the coarse UNC threading maintains secure fastening in vibration-prone environments. With fully threaded design and Class 2A thread fit, these screws distribute clamping forces evenly, preventing joint failure in high-stress assemblies. The combination of 80,000 psi tensile strength and Rockwell B80 hardness ensures these fasteners withstand extreme mechanical loads without deformation.
Specification Summary & Compliance
Manufactured to precise dimensional standards with Class 2A thread fit tolerance and UNC coarse threading (5/16"-18). Complies with ASME B18.6.3 mechanical specifications and maintains regulatory compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental standards. Features include 1/2" length, right-hand thread direction, and Phillips No. 4 drive configuration.
