S-91251A243 5-40 x 3/32" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Exceptional Tensile Strength – With 170,000 psi tensile strength, these screws provide reliable load-bearing capacity for demanding industrial assemblies.
• Superior Corrosion Resistance – The black-oxide finish on alloy steel enhances durability and protects against rust in harsh operating environments.
• Precise Thread Engagement – Class 3A thread fit ensures tight, secure fastening with minimal risk of loosening under vibration or stress.
• High Hardness for Wear Resistance – Rockwell C37 hardness maintains thread integrity and screw head shape through repeated use and high-torque applications.
• Wide Industrial Compliance – Meets ASTM A574, RoHS 3, and REACH standards, ensuring material consistency and environmental safety.
• Optimized for Hex Drive Efficiency – Standard socket head with 3/32" hex drive allows for easy installation and removal in confined spaces.
• Coarse Thread Advantage – 5-40 UNC coarse threads enable quick assembly and reduced cross-threading risk in a variety of materials.

Professional Applications & Engineering Value

This black-oxide alloy steel socket head cap screw is engineered to address critical challenges in precision machinery, automotive, and heavy equipment sectors. The combination of fully threaded design and Class 3A thread fit ensures uniform stress distribution and vibration resistance, reducing maintenance needs in dynamic applications. The high tensile strength and Rockwell C37 hardness prevent stripping and deformation under high clamp loads, while the black-oxide surface treatment adds a layer of corrosion protection without compromising dimensional accuracy. Ideal for use in UNC coarse thread assemblies where reliability and compliance with ASTM A574 are mandatory, these screws deliver long-term performance in rigorous industrial environments.

Specification Summary & Compliance

The screw features a 5-40 UNC coarse thread with Class 3A fit for precise, high-strength fastening. Manufacturing adheres to ASTM A574 specifications, ensuring consistent material properties and dimensional accuracy. The product is fully compliant with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) regulations, confirming its suitability for use in regulated markets and environmentally conscious applications.