Key Precautions for Using High-Strength Nuts — ASM FASTENER Technical Guide

2025-11-28 08:13:14

High-strength nuts are widely used in critical engineering applications thanks to their simple structural design, reliable mechanical performance, fatigue resistance, and stability under dynamic loads. They can also be disassembled easily, making them an essential component in heavy-duty bolted connections.
According to industry practices, high-strength nuts are typically divided into friction-type and bearing-type categories, each serving different connection requirements.

At ASM FASTENER, we emphasize that high-strength nuts must undergo proper anti-corrosion and anti-rust surface protection. A common misconception is that these nuts, due to their excellent mechanical properties, do not require additional treatment. In fact, surface protection is essential for extending service life and ensuring long-term reliability.

Below are the major factors that can cause corrosion or rust on high-strength nuts and must be carefully prevented:

1. Chemical Corrosion in Polluted Environments

In atmospheres containing sulfur compounds, carbon dioxide, or nitrogen oxides, condensed moisture can produce sulfuric, nitric, and acetic acids. These acidic conditions attack the metal surface and accelerate corrosion.

2. Organic Residue-Induced Corrosion

When stainless steel fasteners are contaminated with organic substances such as fruit juice, vegetable residue, soup, or saliva, organic acids may form in the presence of moisture and oxygen. Prolonged exposure to these organic acids leads to localized corrosion on the metal surface.

3. Electrochemical Corrosion from Dust and Foreign Metal Particles

If dust or metallic debris adheres to the nut surface, condensation in humid air can create micro-galvanic cells between these particles and the stainless steel. This triggers electrochemical corrosion and damages the protective oxide film.

4. Corrosion Caused by Acidic or Alkaline Contaminants

Surface contaminants containing acids, alkalis, or salts—such as splashes of limewater or alkaline cleaning solutions—can result in rapid, localized corrosion, especially when left uncleaned for long periods.

Importance of the Friction Coefficient in High-Strength Nut Connections

Beyond corrosion protection, the friction coefficient plays a critical role in determining the load-carrying capacity of high-strength nut connections. Extensive testing has proven that frictional performance is mainly affected by:

• Surface condition of the contact plane

• Material properties of the clamped components

To increase the friction coefficient and ensure joint reliability, ASM FASTENER commonly recommends surface treatments such as:

• Sandblasting

• Steel wire brushing

These methods effectively clean and roughen the contact surfaces within the connection region, enhancing friction and improving the overall performance of high-strength bolted assemblies.

ASM FASTENER — Reliable Supplier for High-Strength Fastening Solutions

With advanced manufacturing capabilities and extensive experience in supplying fasteners for FPSO projects, shipbuilding, petrochemical facilities, and heavy industrial equipment, ASM FASTENER provides high-strength nuts and bolts engineered to meet stringent international standards.

We ensure every product delivers:

• Superior mechanical performance

• Certified material traceability

• Enhanced corrosion resistance

• Reliable performance in extreme environments

Contact ASM FASTENER for high-strength fastening solutions you can trust.