What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
According to relevant standards, the performance grades of carbon steel and alloy steel bolts are divided into more than 10 grades such as 3.6, 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the bolts of grade 8.8 and above are made of low-carbon alloy steel or medium Carbon steel and heat treatment (quenching, tempering) are generally called high-strength bolts, and the rest are generally called ordinary bolts. The bolt performance grade label consists of two parts of numbers, which represent the nominal tensile strength value and yield ratio of the bolt material respectively. Stainless steel bolts are divided into A1-50, A1-70, A1-80, A2-50, A2-70, A2-80, A3-50, A3-70, A3-80, A4-50, A4-70, A4-80, A5-50, A5-70, A5-80, C1-50, C1-70, C1-110, C4-50, C4-70, C3-80, F1-45, F1- 60. The first letter and number represent the stainless steel group, and the second and third numbers represent 1/10 of the tensile strength. [2]
The earliest rivets were small pegs made of wood or bone, and the earliest metal variants may be the ancestors of what we know as rivets. They are without a doubt the oldest known method of joining metals, dating back as far as the earliest use of malleable metals, eg: Bronze Age Egyptians riveted the six wooden sectors of the outer lines of a slotted wheel with rivets Fastened together, after the Greeks had succeeded in casting large statues in bronze, the parts were riveted together with rivets.
In the existing production technology, such as construction machinery, double nuts are often used to fasten the workpiece. With the long-term vibration in the working environment, there is a thread gap between the nut and the bolt, and there is no self-assembly between the nut and the bolt. Locking action, the relative displacement between the nut and the bolt will occur under the action of vibration, resulting in the loosening of the nut and the bolt and the loss of the tightening effect.
screw generally includes a screw head, a screw part and a screw tail. In the traditional screw processing, the screw head and the screw part are punched out first, and then the threaded part is processed on the screw shank through the turning process. When the screw head is traditionally punched, the screw head is easily damaged due to the large punching force.
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