Bolt is a common mechanical parts, often used in many places, it is by the head and screw two parts of a group of fasteners, need to be used in conjunction with the nut, mainly used to fasten the connection of two parts with through holes. Perhaps you do not have any understandings of the grade material of the bolt, this article will introduce you to the bolt material, grade related knowledge, in order to let more people learn to identify these small properties of the bolt.
What do the grades and materials of the bolts refer to?
Bolt grade refers to the bolt is 4.8grade, 8.8 grade, 10.9 grade and other bolt grade.
Material refers to the bolt is made of what material, such as Q235, 35K, 40Cr, 45 # steel, 35CrMo steel, 304 stainless steel and 316 stainless steel and so on.
Bolt grade and material is a certain relationship, mild steel can only produce low strength grade bolts, medium carbon steel can produce medium strength grade bolts, high carbon steel, alloy steel can produce high strength grade bolts. Some bolt grade specifies the corresponding chemical composition and mechanical properties, but also to determine the material.
Here is a list of common grades of bolts can be what material. 4.8 level can be Q235, Q195 and other mild steel material. 5.8 level Q235 above all materials can be, do not need heat treatment. 8.8 level thread diameter of 16MM or less, 35 # tempering heat treatment, 16mm or more, 45 # and low carbon alloy steel tempering. 10.9 level of medium-carbon alloy steel tempering Heat treatment 35Crmo 40Cr and so on.
Can high-strength bolts be distinguished from common bolts by their material?
Generally divided according to the strength grade.
Bolt performance level 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9 and so on more than 10 grades, of which 8.8 and above bolts made of low-carbon alloy steel or medium-carbon steel and heat-treated (quenched, tempered), commonly known as high-strength bolts, the rest of the commonly known as common bolts. Bolt performance level labeling has two parts of the digital composition, respectively, that the nominal tensile strength of the bolt material value and flexural strength ratio value.
For example, the performance level 8.8 grade bolts, the meaning is:
1, bolt material nominal tensile strength of 800MPa level;
2, the bolt material yield strength ratio of 0.8;
3, the nominal yield strength of the bolt material up to 800 × 0.8 = 640MPa level of the most commonly used high-strength bolts for the 8.8 and 10.9 level, the most commonly used ordinary bolts for the 4.8 level.
Post time: Aug-28-2024
