Is Nut Grade The Raw Material Strength Of Nut?

The nut is a very commonly used fastener, and many people may misunderstand it, thinking that the nut grade is the raw material strength of the nut. This idea may be because the bolt grade expresses the bolt material’s corresponding properties; for example, the 8.8 grade bolt clearly shows its tensile strength and yield strength. This extends the misconception that the nut grade is also an intuitive expression of the strength of its raw material.

Understand the true meaning of nut grade and do not simply confuse it with material strength.

The nut grade is mainly determined according to the highest performance grade of the bolt that matches it rather than directly indicating the strength of the nut material itself. For example, a Class 8 nut can be used with a Class 8.8 bolt, but this does not mean that the tensile strength or yield strength of the Class 8 nut is the same as that of the Class 8.8 bolt.

The nut grade does not just refer to the strength of the raw material, but a comprehensive index that integrates the material properties, manufacturing process and design requirements. As a professional fastener manufacturer, Xinchi is happy to give you specific instructions.

Definition of nut grade

The nut grade (such as 4.8, 8.8, 10.9, etc.) usually indicates its mechanical performance grade, which mainly includes two parts:

The number in the first part (such as the “8” in 8.8) represents the tensile strength of the nut material (1/100 of MPa). For example, 8 indicates a tensile strength of 800 MPa.

The numbers in the second part (e.g., “.8 “in 8.8) indicate the yield strength ratio (the ratio of yield strength to tensile strength) of the material. For example, 0.8 means that the yield strength is 80% of the tensile strength, i.e., 800×0.8=640 MPa.

The relationship between strength and grade of raw materials

Raw material strength is an important basis for grades, but grades also involve heat treatment processes (such as quenching and tempering) and processing accuracy.

For example, class 8.8 nuts require medium carbon steel (e.g., 35 steel, 45 steel) and heat treatment to increase strength, while class 10.9 requires alloy steel (e.g, 40Cr, 35CrMo) and more stringent heat treatment.

Other influencing factors of nut grade

Thread accuracy: Higher-grade nuts require more stringent thread tolerances and surface quality.

Durability: including fatigue resistance, corrosion resistance and other properties, which need to be achieved through material selection and surface treatment (such as galvanized, dacromet).

The nut grade is a systematic indicator, and the strength of the raw material is a core factor, but the manufacturing process and design criteria are equally critical. When selecting nuts, it is necessary to consider the grade requirements according to the actual working conditions (load, temperature, corrosion environment, etc.).

XINCHI is a trustworthy fastener company, especially in furniture nuts. We have a factory,  founded in 2007. And we are the designated fastener supplier to“STAPLE”. As a trusted fastener supplier,  XINCHI can offer a wide range of high-quality fasteners, including nuts, screws, bolts, rivets, washers, etc. If you want to know more about fasteners or want to wholesale fasteners, please feel free to contact us. And then our experienced and expert service team will reply to you as soon as possible.