Strength Differences in Steel

Fasteners play a crucial role in various industries, from aerospace to automotive to construction. The right fastener can ensure the safety and reliability of a product or structure, which is why it's essential to choose the right type of steel for the job. In this blog post, we'll be discussing the differences between Class 4.6, Class 8.8, Class 10.9, and Class 12.9 steel, which are commonly used in metric fasteners.

Class 4.6 Steel Class 4.6 steel is a low-grade carbon steel that's commonly used in applications where strength isn't the primary concern. This type of steel is typically used for general-purpose fasteners that require moderate strength and are not subjected to high stress or load. Class 4.6 steel has a minimum tensile strength of 400 MPa and a minimum yield strength of 240 MPa.

Class 8.8 Steel Class 8.8 steel is a medium-strength steel that's commonly used in automotive and construction applications. This type of steel is suitable for fasteners that are subjected to moderate to high stress or load. Class 8.8 steel has a minimum tensile strength of 800 MPa and a minimum yield strength of 640 MPa.

Class 10.9 Steel Class 10.9 steel is a high-strength steel that's commonly used in applications where the fastener is subjected to high stress or load. This type of steel is suitable for critical applications that require high strength and durability. Class 10.9 steel has a minimum tensile strength of 1000 MPa and a minimum yield strength of 900 MPa.

Class 12.9 Steel

Class 12.9 steel is the highest strength steel commonly used in metric fasteners. This type of steel is suitable for applications where the fastener is subjected to extreme stress or load, such as in the aerospace and defense industries. Class 12.9 steel has a minimum tensile strength of 1200 MPa and a minimum yield strength of 1080 MPa. Differences between Class 4.6, Class 8.8, Class 10.9, and Class 12.9 Steel The primary difference between these grades of steel is their strength. Class 4.6 steel is the lowest strength steel used in metric fasteners, while Class 12.9 is the highest. The higher the strength of the steel, the more load it can handle without breaking. As the strength of the steel increases, so does its hardness, which means that it becomes more challenging to machine or form. Another critical difference between these grades of steel is their ductility. Ductility is the ability of a material to deform without breaking. Class 4.6 steel is the most ductile of the four grades, while Class 12.9 is the least ductile. The ductility of a fastener is essential in applications where the fastener is subjected to cyclic loading, as it can prevent fatigue failure.

Conclusion

Choosing the right grade of steel for a fastener is essential to ensure the safety and reliability of the product or structure. Class 4.6, Class 8.8, Class 10.9, and Class 12.9 steel are commonly used in metric fasteners, and each grade has its unique properties. Class 4.6 steel is suitable for general-purpose applications, while Class 12.9 steel is suitable for critical applications that require high strength and durability. Understanding the differences between these grades of steel can help you choose the right type of steel for your application.