There are actually no specific regulations for the material of grade 8.8 bolts, only the range of chemical compositions allowed to be used is specified. As long as the material meets the requirements within this specified range, it can be used as a material for grade 8.8 high-strength bolts. However, many professionals will still regard the standard of grade 8.8 bolts as an important reference for material selection.
In order to meet the performance requirements of grade 8.8 bolts with different requirements, the material must undergo special heat treatment to achieve the following characteristics:
1. The nominal tensile strength of the bolt material reaches up to 640MPa;
2. The yield-to-strength ratio of the bolt material is 0.8;
3. The nominal yield strength of the bolt material reaches 640×0.8=800MPa level;
4. When selecting materials, grade 8.8 hexagonal bolts can use 1035ACR (applicable to M10 and below) and 1040ACR (applicable to M12 and above), CH38F, 1045ACR, 1039, 10B21, 10B33, 10B38 and other materials;
5. Grade 8.8 hexagon socket head bolts can use CH38F, 1039, 10B21 (applicable to M10-M12), 10B33 (applicable to M14), 10B38 (applicable to M12-M24), 1035ACR (applicable to M10 and below) and 1040ACR (applicable to M12 or above) and other materials;
6. The discs used in carbon steel products can be made of different materials according to different types. For example, grade 4.8 hexagonal bolts can use 1008K, 1010, 1015K and other materials, and grade 6.8 hexagonal bolts can use 1032, 1035, 1040, CH38F, 1039, etc. Material, grade 8.8 hexagonal bolts can use 1035ACR (applicable to M10 and below) and 1040ACR (applicable to M12 and above), CH38F, 1045ACR, 1039, 10B21, 10B33, 10B38 and other materials. Grade 8.8 hexagon socket bolts can use CH38F, 1039, 10B21 (applicable to M10-M12), 10B33 (applicable to M14), 10B38 (applicable to M12-M24), 1035ACR (applicable to M10 below) and 1040ACR (applicable to M12 and above) and other materials, 10.9 grade hexagonal bolts can use 1045ACR , 10B38 and other materials. Grade 8 and above nuts can use materials such as 1015 (M<16) and CH38F (M≥16). Grade 10 nuts can use materials such as CH38F, 1039, 10B21, 10B33, etc. Grade 12 nuts Caps can be made of materials such as 1039, 10B21, 10B33 and 10B38; carriage screws can be made of materials such as 1008, 1010 and 1015; hexagonal flange bolts can be made of CH38F, 1039, 10B21, 10B33, 10B38 and other materials; hexagonal wood screws can be made of 1008K, 1010 and other materials, self-tapping nails, wallboard nails, drilled nails, plywood nails can use 1018, 1022, CH22A and other materials.
Fully understanding the material and performance requirements of grade 8.8 bolts can help you better choose suitable materials to meet your engineering needs.
