What are the differences between hexagonal socket screws that make industrial design inseparable from them

What are the differences between hexagonal socket screws that make industrial design inseparable from them

The so-called hexagonal bolt refers to a cylindrical head with an hexagonal shape, which can also be referred to as an hexagonal screw, hexagonal cylindrical head screw, and hexagonal screw.

Internal hexagonal hardness and performance

The commonly used hexagonal bolts we use in general include grades 4.8, 8.8, 10.9, 12.9, etc. In general, different grades of hexagonal bolts are selected based on different needs in order to better enhance the performance of the bolts. Today, let's talk about the hardness levels of hexagonal bolts.

Hardness level

Hexagon bolts are classified according to the hardness, tensile strength, yield strength, etc. of the screw wire, which is the grade of the hexagon bolt and what grade the hexagon bolt is. Different grades of hexagonal bolts are required to correspond to different product materials.

Hexagon bolts are divided into ordinary and high-strength bolts according to their strength levels. Ordinary hexagonal bolts refer to grade 4.8, while high-strength hexagonal bolts refer to grades 8.8 and above, including grades 10.9 and 12.9. Grade 12.9 hex socket bolts generally refer to black hex socket cup head screws with knurled and naturally colored oil.

The performance grades of hexagonal socket bolts for steel structural join can be divided into more than 10 grades, including 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9 and 12.9. The bolts of grade 8.8 and above are collectively referred to as high-strength bolts. The bolts are made of low-carbon alloy steel or medium carbon steel and heat treated. The rest are generally referred to as ordinary bolts. The bolt performance grade label consists of two parts of numbers, representing the nominal tensile strength value and yield strength ratio of the bolt material.

Performance level

The bolt performance grade label consists of two parts of numbers, representing the nominal tensile strength value and yield strength ratio of the bolt material.

The meaning of bolts with a performance level of 4.6 is:

1. The nominal tensile strength of bolt material reaches 400MPa level;

2. The yield strength ratio of bolt material is 0.6; The nominal yield strength of bolt material reaches 400 × 0.6=240MPa level.

Performance grade 10.9 high-strength bolts, after heat treatment, can achieve:

1. The nominal tensile strength of bolt material reaches 1000MPa level;

2. The yield strength ratio of bolt material is 0.9; The nominal yield strength of bolt material reaches 1000 × 0.9=900MPa level.

The meaning of the performance grade of hexagonal socket bolts is an internationally recognized standard. Bolts with the same performance grade, regardless of their material and origin, have the same performance, and only the performance grade can be selected for design.

The prices in the market will definitely vary depending on the level. The price of high-strength hexagonal bolts is definitely much higher than that of ordinary hexagonal bolts. The four types commonly used in the market are 4.8, 8.8, 10.9, and 12.9.