S-91268A980 2"-4 1/2 x 8" ASME B18.2.1, ASTM A354BD High-Strength Grade 8 Steel Hex Head Screws

Key Features & Benefits at a Glance

• Exceptional tensile strength of 150,000 psi ensures reliable performance under extreme loads, reducing the risk of fastener failure in critical applications.
• High hardness rating (Rockwell C33) provides superior resistance to wear and deformation, extending service life in abrasive environments.
• Grade 8 steel construction with ASTM A354BD specification guarantees consistent material quality and high strength-to-weight ratio for demanding industrial uses.
• Coarse UNC threading with Class 2A fit allows for quicker assembly and better vibration resistance compared to fine threads, improving installation efficiency.
• Partially threaded design concentrates strength where needed most, preventing thread damage and ensuring secure clamping in structural connections.
• External hex drive with 3" head width enables high-torque installation using standard tools, reducing stripping risks and maintenance downtime.
• Full compliance with ASME B18.2.1 ensures dimensional accuracy and interchangeability, simplifying procurement and replacement processes.

Professional Applications & Engineering Value

These Grade 8 hex head screws are engineered to solve critical fastening challenges in heavy machinery, structural steel frameworks, and high-vibration equipment. The ASTM A354BD steel composition combined with Rockwell C33 hardness provides exceptional resistance to shock loads and fatigue, making them ideal for construction, mining, and transportation applications where joint integrity is paramount. The coarse UNC threading maintains grip under dynamic stresses, while the partial threading design prevents thread galling in tapped holes. With 150,000 psi tensile strength, these heavy-duty steel fasteners deliver reliable performance in bolted connections subject to extreme tension and shear forces, reducing maintenance frequency and improving operational safety.

Specification Summary & Compliance

These screws feature 2"-4 1/2 UNC coarse threads with Class 2A thread fit for standard clearance applications. Manufacturing complies with ASME B18.2.1 dimensional specifications and ASTM A354BD material requirements. The products are fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) environmental regulations, ensuring safe use in regulated industries.