Bulk 5/16″-18 Grade A Hex Bolts (A307, Coarse Thread, Zinc CR+3)

Strong and Reliable Fasteners for Construction, Industrial, and Structural Use

For applications requiring high-strength, durable fasteners, trust 5/16″-18 ASTM A307 Grade A Hex Bolts. Manufactured from low carbon steel and zinc-coated with Cr+3 for corrosion resistance, these bolts are a top choice for construction, infrastructure, and general-purpose fastening.

Note PT = Partial Thread

Key Specifications

• Material: Low carbon steel (ASTM A307 Grade A compliant)
• Tensile Strength: 60,000 psi minimum tensile strength
• Thread Size: 5/16″-18 Coarse Thread (UNC)
• Finish: Zinc CR+3 (trivalent chromate) for enhanced corrosion resistance
• Head Style: Standard hex head for easy wrench tightening
• Compliance: Fully meets ASTM A307 Grade A specifications

Differences Between ASTM A307 Grade A & B

Understanding the differences between A307 Grade A and Grade B is crucial for selecting the right bolt for your project:

• Grade A: Designed for general-purpose applications, including construction, infrastructure, and industrial equipment fastening. These bolts have a minimum tensile strength of 60,000 psi and are widely used for everyday structural needs.
• Grade B: Specifically made for flanged joints in piping systems with cast iron flanges. These bolts have a slightly higher tensile range (60,000 to 100,000 psi) and require heavy hex heads for added strength.
• Why Choose Grade A for 5/16″-18 Hex Bolts? Grade A is ideal for securing structural elements, mounting heavy equipment, and general-purpose fastening. Its broad usability makes it the go-to choice for large-scale construction projects.

Benefits of ASTM A307 Grade A

• Versatile Construction Fastener: Commonly used in commercial buildings, bridges, and heavy equipment manufacturing.
• Reliable Strength: With a minimum tensile strength of 60,000 psi, these bolts provide secure fastening in critical applications.
• Corrosion Resistance: The Zinc CR+3 plating extends bolt lifespan by providing a protective barrier against moisture and oxidation.
• Standard Compatibility: Easily integrates with standard nuts and washers, making replacement and installation simple.

Industries & Applications

• Structural Steel & Construction: Ideal for bolted connections in commercial buildings, bridges, and heavy-duty frameworks.
• Industrial Equipment Manufacturing: Used in assembling and securing large machinery and support structures.
• Infrastructure & Civil Engineering: Essential for securing steel beams, anchoring systems, and structural fastenings.
• General-Purpose Fastening: Perfect for securing wood, concrete, and metal components in industrial settings.

Installation Tips

• Use the Right Wrench: Standard hex head bolts require an appropriately sized wrench or impact socket for installation.
• Torque Properly: Follow recommended torque guidelines to avoid over-tightening or under-tightening, ensuring optimal performance.
• Secure with Matching Hardware: Always use A307-compatible nuts and washers to maintain strength and stability.
• Check for Corrosion Resistance: The zinc-plated finish protects against moisture, but regular inspections ensure long-term durability.

Bulk Purchasing Advantages

• Cost Savings: Buying in bulk lowers the per-unit cost, making large projects more affordable.
• Consistent Quality: All bulk orders are sourced from the same production lot, ensuring uniform strength and reliability.
• Fast Availability: Large stock ensures quick fulfillment, keeping your project on schedule.
• Ideal for Contractors & Manufacturers: Whether you’re assembling heavy machinery or working on a large-scale build, having a bulk supply reduces downtime.

Order in Bulk & Save

Upgrade your construction and industrial fastening with bulk 5/16″-18 ASTM A307 Grade A Hex Bolts. Perfect for structural connections, equipment mounting, and general fastening. Order now for bulk discounts, fast shipping, and expert customer service.

Best for industrial, structural, and heavy machinery projects

Coarse-thread UNC design for strong and secure fastening

ASTM A307 Grade A compliant for reliable performance

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