Tire bolt
Tire bolt material: 45#steel, 40Cr and35CrMO
The bolt grade: 8.8, 10.9 and 12.9
The bolts above M24 adopt with Hot upsetting process, through High temperature spheroidizing annealing, the hardness can be improved to HRC34-40 and the tensile strength to 1040mpa, the surface impurities are removed after pickling and the needed color is gained by electroplating, dacromet or phosphating; as to the bolts below M24, mostly adopt with cold upsetting process which has the features of large output (over 300 pieces per minute), good surface finish and tight material composition. The thread are machined through rolling process of chipless machining with high productivity, the precision can reach 4h and the surface roughness can reach Ra0.2um, compared with the thread cutting, the thread rolling can save the cost of 16-25%.
