S-94705A817 1 1/8"-8 x 4 3/4" 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 under extreme loads, reducing the risk of fastener failure in critical applications.
• High hardness rating (Rockwell C35) provides superior resistance to wear and deformation, extending service life in demanding environments.
• Partially threaded design offers a secure, non-threaded grip length for precise clamping force distribution and vibration resistance.
• UN fine thread with Class 2A fit delivers smooth, accurate engagement and improved fatigue resistance compared to coarse threads.
• External hex drive and hex head allow for easy installation and high torque application using standard tools, speeding up assembly processes.
• Manufactured from ASTM Grade B7 steel, this screw maintains strength at elevated temperatures, ideal for pressure vessels and high-stress assemblies.
• Compliant with ASTM A193 specifications, ensuring consistent quality, material traceability, and suitability for high-pressure and high-temperature services.

Professional Applications & Engineering Value

This 1 1/8"-8 hex head screw is engineered to address common industrial challenges such as joint integrity under dynamic loads and thermal cycling. Constructed from ASTM Grade B7 steel, it offers excellent creep resistance and retains its 125,000 PSI tensile strength even in high-temperature environments up to 800°F, preventing loosening in systems like pressure vessels, valves, and flanges. The UN fine thread and Class 2A thread fit provide superior fatigue performance and leak-proof sealing in pressurized applications. With a partially threaded shank, it ensures that the unthreaded grip length bears the clamp load directly, minimizing stress concentration on the threads. This design is critical for heavy-duty industrial fasteners used in oil and gas, power generation, and chemical processing, where safety and durability are paramount.

Specification Summary & Compliance

This screw features a 1 1/8"-8 UN fine thread with Class 2A thread fit for precise dimensional accuracy and easy assembly. It is manufactured in accordance with ASTM A193 specifications, covering high-temperature alloy steel bolting materials. The product meets the mechanical property requirements for ASTM Grade B7, including tensile strength and hardness, and is suitable for use in applications requiring compliance with ASME boiler and pressure vessel codes. Material composition and manufacturing processes adhere to industry standards, ensuring reliability for critical engineering applications.