What Is Fastener Tensile Strength and Yield Strength?

When selecting fasteners, understanding tensile strength and yield strength is crucial. These properties define how much force a fastener can withstand before deforming or breaking. Whether securing heavy loads or designing critical structures, choosing the right fastener can save time, money, and potential failures. In this article, we’ll break down these concepts in a beginner-friendly way, ensuring you’re equipped to make informed decisions.

Tensile Strength

Tensile strength, or ultimate tensile strength (UTS), is the maximum force a fastener can endure before fracturing. This property is a key factor in determining a fastener’s suitability for heavy-duty applications exposed to significant loads. Tensile strength is influenced by material composition, hardness, and fastener size.

How to Determine the Tensile Strength of a Fastener?

Fasteners undergo a wedge tensile test to measure tensile strength. Here’s how it works:

• To increase tension at the point where the fastener’s head and body meet, a wedge is positioned beneath the head.
• Force is applied until the fastener breaks.
• The fastener passes the test if it can sustain a force greater than the minimum required without breaking at the junction.

The test confirms whether the fastener meets industry standards, such as ISO 898-1 or ASTM specifications.

FAQs

• What is tensile testing of fasteners?
  • Tensile testing measures the maximum force a fastener can withstand before fracturing. It ensures compliance with quality standards.
• What do high-tensile fasteners mean?
  • High-tensile fasteners are designed to endure greater forces, making them ideal for demanding applications like construction and heavy machinery.

Yield Strength

Yield strength refers to the load at which a fastener begins to deform permanently. Unlike tensile strength, which marks the point of fracture, yield strength defines the threshold where the material’s elasticity is exceeded, causing irreversible changes to its shape.

How to Calculate Yield Load

Yield load is calculated using a tensile machine and the offset method. Here’s the process:

• The fastener is placed in a tensile machine, and the load is gradually applied.
• Elongation is measured, and results are plotted on a stress-strain diagram.
• Yield strength is identified at a 0.2% offset from the initial linear curve.

This testing ensures the fastener meets specific grade or property class requirements, such as ASTM A354 standards. For example, ASTM A354 Grade BC fasteners have a yield strength ranging from 94,000 psi to 130,000 psi, depending on size.

Fastener Tensile Strength vs. Yield Strength: Which Is More Important?

Choosing between tensile strength and yield strength depends on the application. Here’s how to decide:

• When to prioritize tensile strength: For fasteners exposed to extreme forces, such as bridge or machinery components, tensile strength ensures they won’t break under load.
• When to prioritize yield strength: In applications where deformation must be avoided, such as precision assembly or structural support, yield strength is critical.

Environmental factors, like temperature and load conditions, also play a role. Excessive heat can reduce both tensile and yield strength, making choosing fasteners rated for specific environments vital.

Conclusion: Trust CNRL Fasteners for Reliable Solutions

At CNRL Fasteners, we specialize in providing high-quality fasteners that meet stringent industry standards. Our extensive range includes products with exceptional tensile and yield strength, ensuring safety and performance for your projects.

Explore our premium fasteners, including:

• Hexagon Lock Nut with Flange
• Metric Zinc-Plated Heavy Hex Nylon Lock Nuts

CNRL Fasteners combines expertise, variety, and reliability, making us your go-to source for fasteners that perform under pressure. Contact us today for solutions tailored to your needs.