S-94705A834 1 1/4"-8 x 4" ASTM A193 Steel Heavy Hex Head Screws for High-Pressure Applications

Key Features & Benefits at a Glance

• Exceptional tensile strength of 125,000 PSI ensures reliable performance in high-stress industrial environments, reducing the risk of fastener failure.
• Superior hardness rating of Rockwell C35 provides excellent resistance to wear and deformation, extending service life in demanding applications.
• Precise Class 2A thread fit guarantees smooth assembly and secure fastening, minimizing installation time and improving joint integrity.
• Partially threaded design offers optimal grip length control, allowing for focused clamping force where it's needed most in structural connections.
• External hex drive configuration enables high-torque installation with standard tools, facilitating quick maintenance and disassembly.
• Full ASTM A193 compliance ensures material quality and manufacturing consistency, meeting rigorous industry standards for critical applications.
• UN fine threading provides enhanced vibration resistance compared to coarse threads, maintaining clamp load in dynamic operating conditions.

Professional Applications & Engineering Value

This ASTM Grade B7 hex head screw delivers critical performance advantages for heavy-duty industrial applications where reliability is paramount. The high-strength steel construction combined with Rockwell C35 hardness addresses common failure modes in pressure vessels, structural steel connections, and high-temperature environments. The partially threaded design with 1 1/4" grip length concentrates clamping force precisely where needed, while the UN fine thread pattern and Class 2A thread fit ensure consistent preload and superior vibration resistance. These engineering features make this external hex drive fastener ideal for critical bolting applications in petrochemical, power generation, and heavy machinery sectors where 125,000 PSI tensile strength and dimensional precision are essential for operational safety.

Specification Summary & Compliance

This hex head screw features 1 1/4"-8 UN fine threads with Class 2A thread fit tolerance for precision assembly. The 4" length includes 2 3/4" thread length and 1 1/4" grip length for optimal clamping performance. Manufactured to ASTM A193 specification for Grade B7 bolting materials, this inch system fastener meets industry standards for high-temperature service and pressure boundary applications. The right-hand thread direction and external hex drive design comply with industrial fastening conventions for compatibility with standard installation tools and procedures.