Service HotlineThe drawing process has two purposes, one is to modify the size of the raw materials; the other is to obtain basic mechanical properties of the fasteners through deformation and strengthening. For medium carbon steel, medium carbon alloy steel also has another purpose, that is, to make the wire rod. The flaky cementite obtained after controlled cooling is cracked as much as possible during the drawing process to prepare for the subsequent spheroidization (softening) annealing to obtain granular cementite. However, some manufacturers arbitrarily reduce the drawing in order to reduce costs. The excessive reduction rate increases the work hardening tendency of the wire rod, which directly affects the cold heading performance of the wire rod. If the distribution of the reduction ratio of each pass is not appropriate, it will also cause torsional cracks in the wire rod during the drawing process. In addition, if the lubrication is not good during the drawing process, it can also cause regular transverse cracks in the cold drawn wire rod. The tangential direction of the wire rod and the wire drawing die is not concentric at the same time when the wire rod is rolled out of the die, which will cause the wear of the unilateral hole pattern of the wire drawing die to aggravate, make the inner hole out of round, and cause uneven drawing deformation in the circumferential direction of the wire. The roundness of the steel wire is out of tolerance, and the cross-sectional stress of the steel wire is not uniform during the cold heading process, which affects the cold heading pass rate. During the drawing process of the wire rod, the excessive surface reduction ratio will deteriorate the surface quality of the steel wire, while the too low surface reduction ratio is not conducive to the crushing of the flaky cementite, and it is difficult to obtain as much granular cementite as possible. , that is, the spheroidization rate of cementite is low, which is extremely unfavorable to the cold heading performance of the steel wire. For the bar and wire rod produced by the drawing method, the partial surface reduction rate is directly controlled within the range of 10%-15%.
The common types of wood screws are iron and copper, and the types are divided into round head type and other samples of wood screws according to different nail heads. There are two types of slotted screws and cross recessed screws. Generally, the round head screws are made of mild steel and are blue, and the flat head screws are polished. The oval head screws are usually plated with cadmium and chrome, and are often used to install hinges, hooks and other hardware accessories. Specifications are determined by rod diameter, length and nail head type. [1]
Nuts and washers are both small and medium-sized components of the tension reinforcement system, and they are easily lost on the construction site when used separately, which is not conducive to the storage management of turnover materials; 3) During the process of formwork support and removal, they must be installed individually And demolition, thus adding a construction process, affecting the efficiency of construction.
The spring washer can prevent loosening and increase the pre-tightening force, while the flat washer does not have this function. It can be used to increase the tightening contact area, prevent the friction between the bolt and the workpiece, and protect the surface of the connector to prevent bolts. The surface of the workpiece is scratched when the nut is tightened. However, for some important connections, such as places that rely mainly on compression to generate frictional force to transmit power, spring pads cannot be used, and the rigidity of the connection is reduced, which is prone to accidents. Spring washers can be omitted. When the strength of the connected parts is low, use flat washers or flange bolts to increase the contact area. When there is vibration, pulse, and the temperature of the medium fluctuates greatly, spring washers must be used.
The traditional dismantling of automobile girder rivets is mostly carried out manually, which has many defects such as long disassembly time, low disassembly efficiency, labor-intensive, time-consuming, labor-intensive, low operation safety, difficult protection, and easy injury.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: flat bottom plastic support column, core screw, dome head bolt, machinery industry and other products, we can provide you with suitable fastener solutions for you Program.
