Ductile iron bolt products

Ductile iron bolt products can be divided into a, B and C grades according to the manufacturing accuracy. For connecting bolts used in steel structure, unless otherwise specified, they are generally common rough C-grade bolts. There are differences in the processing methods of different levels, and the corresponding processing methods are as follows: ① the bolt rod of Grade A and B bolts is processed by lathe, with smooth surface and accurate size. Its material performance grade is 8.8, and its production and installation are complex, and its price is high, so it is rarely used; ② Grade C bolts are made of raw round steel, the size is not accurate enough, and the material property grade is grade 4.6 or 4.8. Shear connection has large deformation, but it is easy to install and has low production cost. It is mostly used for tensile connection or temporary fixation during installation.
Generally, the countersunk head is used in the place where the surface after connection is required to be smooth without protrusion, because the countersunk head can be screwed into the parts. The round head can also be screwed into the part. The tightening force of square head can be larger, but the size is large. In addition, in order to meet the needs of locking after installation, there are holes in the head and in the rod, which can prevent the bolts from loosening when they are subject to vibration. Some bolts have no thread of light rod to do thin, called thin waist bolt. This kind of bolt is beneficial to the connection under variable force. There are one-to-one bolts with good strength on the steel structure, the head will be larger, and the size will also change. In addition, there are special uses: T-shaped slot bolt, machine tool fixture used more, special shape, both sides of the head to cut off. Anchor bolts are used to connect the machine and the ground. There are many shapes. U-bolt, as previously mentioned. wait. There are also one-to-one studs for welding, one with thread and the other without thread, which can be welded on the parts, and the other side can directly screw the nut.