Ask the Fastener Expert: Grade 8 Bolts and Nuts
What does Grade 8 mean in fasteners?
In the U.S., a Grade 8 fastener is made of medium carbon alloy steel, quenched and tempered, and has a tensile strength of at least 150,000 psi. These fasteners are designated as Grade 8 because they meet or exceed the minimum tensile strength requirements for this grade as outlined in the SAE J429 standard. Grade 8 fasteners are often used in automotive and construction applications where high strength is required. They may also be plated with a finish, such as zinc or black oxide, to improve corrosion resistance.
What are the benefits of Grade 8 fasteners?
Some benefits of using Grade 8 fasteners include:
High strength: With a minimum tensile strength of 150,000 psi, Grade 8 fasteners are much stronger than most other fasteners on the market. This makes them suitable for use in applications where high loads or forces are present.
Durability: Grade 8 fasteners are made of high-strength alloy steel and are heat-treated to make them more durable and resistant to wear and tear. This makes them suitable for use in demanding applications where they may be subjected to high levels of stress or strain.
Corrosion resistance: Some Grade 8 fasteners are plated with a finish, such as zinc or black oxide, to improve their corrosion resistance. This makes them suitable for use in outdoor or humid environments where corrosion may be a concern.
Versatility: Grade 8 fasteners are available in a wide range of sizes and styles, including bolts, screws, nuts, and washers. This makes them suitable for use in a variety of applications and allows them to be used in conjunction with other fasteners.
Cost-effectiveness: While Grade 8 fasteners may be more expensive than other grades of fasteners, their high strength and durability often make them a cost-effective choice in the long run. They can save money by reducing maintenance costs and downtime due to fastener failure.
In what applications are Grade 8 fasteners required?
Grade 8 fasteners are often used in applications where high strength is required. Some examples include:
Automotive: Grade 8 fasteners are commonly used in the automotive industry to secure engine components and other parts that are subjected to high loads or forces.
Construction: Grade 8 fasteners are used in construction to secure beams, columns, and other structural elements. They may also be used to fasten heavy equipment or machinery to foundations or other support structures.
Military: Grade 8 fasteners are used in military applications where high strength and durability are critical, such as in the construction of military vehicles and equipment.
Aerospace: Grade 8 fasteners are used in the aerospace industry to secure aircraft components and other parts that are subjected to high loads or forces.
Industrial: Grade 8 fasteners are used in a variety of industrial applications, including the manufacture of machinery, heavy equipment, and other industrial products. They may also be used in the oil and gas industry to secure pipelines and other structures.
Are there any downsides to using Grade 8 fasteners?
Some potential downsides to using Grade 8 fasteners include:
Cost: Grade 8 fasteners are typically more expensive than other grades of fasteners, such as Grade 2 or Grade 5. This can make them a less cost-effective option in some applications.
Brittleness: Grade 8 fasteners are made of high-strength alloy steel and are heat-treated to increase their strength. However, this heat-treatment process can also make them more brittle, which can increase the risk of fastener failure if they are subjected to too much stress or strain.
Over-tightening: It is important to tighten Grade 8 fasteners to the proper torque specification to ensure that they are secured properly. If they are overtightened, the fasteners can be damaged or even break, which can lead to fastener failure.
Compatibility: Grade 8 fasteners may not be compatible with all materials. For example, if they are used to fasten soft materials such as aluminum or brass, the threads may strip or the fasteners may fail due to the lack of sufficient gripping power. It is important to ensure that Grade 8 fasteners are used with materials that they are compatible with to avoid problems.
If you’d like more information about Grade 8 nuts and bolts, contact Mudge Fasteners at (800) 634-0406.