S-91251A596 5/16"-18 x 3 1/4" ASTM A574 Alloy Steel Socket Head Screws

Key Features & Benefits at a Glance

• Superior tensile strength of 170,000 psi ensures reliable performance in high-stress applications, reducing the risk of fastener failure.
• Exceptional hardness rating (Rockwell C37) provides excellent wear resistance and durability for long-term use in demanding environments.
• Precision Class 3A thread fit guarantees tight tolerances and secure fastening, minimizing vibration loosening in machinery.
• Black-oxide coating on alloy steel offers enhanced corrosion resistance and a professional finish without compromising dimensional integrity.
• Standard hex socket drive allows for easy installation with common tools, reducing assembly time and improving workflow efficiency.
• Coarse UNC threads enable quick engagement and are less prone to clogging in dirty or debris-filled industrial settings.
• Partially threaded design provides optimal grip and clamping force where full threading isn't required, offering versatile application use.

Professional Applications & Engineering Value

This 5/16"-18 UNC Socket Head Cap Screw is engineered to address critical challenges in industrial assembly and machinery. The black-oxide alloy steel construction combats rust and wear, extending service life in harsh conditions like manufacturing plants or outdoor equipment. Its coarse thread design ensures rapid installation and reliable holding power, even in applications with vibration or dynamic loads. The Class 3A thread fit provides precise alignment, reducing the risk of cross-threading and ensuring consistent performance in automated production lines. Ideal for heavy-duty applications such as automotive frames, industrial robots, and construction machinery, this fastener delivers high tensile strength and compliance with rigorous standards, making it a trusted choice for engineers seeking durability and efficiency.

Specification Summary & Compliance

This product features a Class 3A thread fit with UNC coarse threads, ensuring high precision and interchangeability. It meets ASTM A574 specifications for alloy steel socket head cap screws, guaranteeing consistent quality and performance. Compliance with RoHS 3 (2015/863/EU) and REACH (EC 1907/2006) confirms adherence to environmental and safety regulations, making it suitable for global industrial markets.