Grade 8 Fasteners | Yellow Zinc

Grade 8 Fasteners: High-Strength Yellow Zinc Solutions

Grade 8 fasteners represent the highest-strength standard in SAE J429 specifications, offering exceptional performance with a distinctive yellow zinc finish. These premium fasteners are manufactured from medium carbon alloy steel, quenched and tempered to achieve a minimum tensile strength of 150,000 PSI, making them ideal for critical applications where maximum strength and reliability are essential.

Our comprehensive selection includes Grade 8 bolts, nuts, washers, and screws, all featuring the characteristic yellow zinc plating that not only provides superior corrosion protection but also serves as a visual indicator of their high-strength classification. Each fastener is marked with six radial lines on the head, ensuring easy identification and proper specification compliance.

Key Features and Benefits

  • Superior Strength: 150,000 PSI minimum tensile strength
  • Enhanced Corrosion Protection: Yellow zinc plating offers 2-3x more corrosion resistance than clear zinc
  • Easy Identification: Distinctive yellow finish and six radial head markings
  • Quality Assurance: Meets or exceeds SAE J429 Grade 8 specifications
  • Versatile Applications: Ideal for high-stress and critical assembly requirements

Material and Performance Specifications

Material Properties:

  • Medium carbon alloy steel, quenched and tempered
  • Core hardness: Rockwell C33-C39
  • Proof load strength: 120,000 PSI
  • Yellow zinc plating with hexavalent chromate conversion coating

Salt Spray Performance:

  • Up to 96 hours salt spray resistance
  • Superior protection compared to clear zinc finishes
  • Self-healing properties for enhanced durability

Common Applications

Automotive and Heavy Equipment:

  • Suspension systems
  • Engine mounting
  • Chassis components
  • Drivetrain assemblies

Industrial Applications:

  • Heavy machinery assembly
  • Structural connections
  • High-stress mounting points
  • Critical equipment installation

Product Selection Guide

Grade 8 Bolts and Screws

  • Available in hex head and socket head styles
  • Coarse and fine thread options
  • Sizes from 1/4" through 1-1/2"
  • Multiple length options

Grade 8 Nuts

  • Heavy hex and finished hex styles
  • Compatible with Grade 8 bolts
  • Through-hardened for maximum strength
  • Yellow zinc plated for corrosion resistance

Frequently Asked Questions

What makes Grade 8 fasteners different from other grades?

Grade 8 fasteners are made from medium carbon alloy steel and heat-treated to achieve the highest strength rating in the SAE J429 specification (150,000 PSI minimum tensile strength). They feature six radial lines on the head and typically come with yellow zinc plating for enhanced corrosion protection.

Why are Grade 8 fasteners yellow?

The yellow color comes from a specialized zinc plating process with a yellow chromate conversion coating. This finish provides superior corrosion protection compared to clear zinc plating and serves as a visual identifier for high-strength Grade 8 fasteners.

Can Grade 8 fasteners be used in all applications?

While Grade 8 fasteners offer superior strength, they may not be the best choice for all applications. They are typically used in high-stress situations requiring maximum strength and should be installed to proper torque specifications. For general-purpose applications, Grade 5 fasteners may be more cost-effective.

What's the difference between yellow zinc and clear zinc plating?

Yellow zinc plating includes an additional chromate conversion coating that provides 2-3 times more corrosion resistance than clear zinc plating. The yellow finish also helps identify high-strength fasteners, as most Grade 8 fasteners use this distinctive coating.