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Fastener grades are not just numbers or markings used for random categorization. Quite the opposite. These grades significantly impact the quality, durability, and safety of products.

Each grade represents the material’s strength, hardness, and suitability for various applications. In this way, grades help manufacturers choose the most appropriate fastener for a specific use. It also ensures the final product can hold up to the required loads and environmental conditions.

For instance, higher grade fasteners are ‌stronger and more durable than their lower grade counterparts. This makes them ideal for high stress applications, such as automotive or aerospace. Cost effective, lower grade, fasteners may be sufficient for less demanding applications without compromising safety.

Understanding grades requires knowing the specifications behind the grade.

Grade Specifications

Grade specifications directly relate to a fastener’s material strength.

Higher grades suggest the fastener can stand up to more tension or pulling force before failing. Various grades may also indicate different material compositions.

For example, steel fasteners might have different alloying elements at various concentrations, which affect their properties. Known for their strength and lightweight characteristics, Grade 5 titanium fasteners vary across Grades 2, 5, 7, and 23, each offering distinct properties and benefits.

In addition, grades like Grade 8 align with industry standards such as those established by the American Society for Testing and Materials (ASTM) and Society of Automotive Engineers (SAE).

Material and Mechanical Properties

The composition of different grades, such as the makeup of Grade 5 Titanium Fasteners (approximately 4% vanadium, 6% aluminum, and 90% titanium) influences their mechanical properties. These include:

  • Tensile strength
  • Corrosion resistance
  • Suitability for specific environments

The SAE offers 3 basic grades to choose from:

  • Grade 2: Composed of medium to low carbon steel, available in diameters from ¼” to 1-½”.
  • Grade 5: Made from medium carbon, tempered and quenched steel, also available in ¼” to 1-½” diameters.
  • Grade 8: Available in ¼” to 1-½” diameters, made from alloyed medium carbon steel, tempered and quenched. (Note: The high strength of Grade 8 bolts makes them ideal for applications such as tractor and truck fabrication).

Corrosion Resistance and Coatings

Coatings and treatments can enhance the longevity and performance of these grades in various environments. Read more about coating HERE.

Trends in Fastener Grades

In the near future we can expect to see stronger and lighter materials for fasteners such as advanced titanium alloys and carbon fiber composites. These innovations will not only enhance performance but reduce the overall weight of products. This, in turn, is expected to lead to greater energy efficiency in applications, particularly within the automotive and aerospace industries.

When deciding on a grade, consult with your fastener distributor to find the specific best grade for your application.

For further information and for assistance in choosing the right grade for your project, contact us at [email protected], send us a chat message or call us at: 973-227-0045.

About the Author

Larry Melone
By Larry Melone

Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.

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