10.9 Screw What Does It Mean?

There are often customers who ask for grade 10.9 screw. What does this mean? When I first came into contact with the screw industry, I still don’t know what it means. Does the screw have a grade requirement? So I went to ask our technical master, the master told me that the 10.9 level is the strength level of the screw. I only know that the original screw has strength.

After the screw is finished, heat treatment can increase the strength of the screw. Carbon steel screws can be divided into more than 10 grades of 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9. Among them, the 8.8 grade and above screws are made of low carbon alloy steel or medium carbon steel and heat treated (quenched and tempered). They are commonly referred to as high strength screws. Other grades are commonly referred to as ordinary screws.

The performance rating of the screw is composed of two parts, which represent the nominal tensile strength and yield ratio of the bolt material. For example, a bolt with a performance rating of 4.6 means:

★The nominal tensile strength of bolt material is up to 400MPa;

★The yield ratio of the bolt material is 0.6;

★The nominal yield strength of bolt material reaches 400×0.6=240MPa grade performance grade 10.9 screw high strength bolt. After heat treatment, the material can reach:

★The nominal tensile strength of bolt material is up to 1000MPa;

★The yield ratio of the bolt material is 0.9;

★The nominal yield strength of the bolt material is 1000×0.9=900MPa

If you want to know more about 10.9 screw or other screw fasteners, please feel free to contact us at annie.li@szsst88.com