The forming of the bolt head adopts cold heading plastic processing. Compared with cutting processing, the metal fiber (metal wire) is continuous along the shape of the product without cutting in the middle, thus improving the strength of the product, especially the mechanical properties.
The cold heading forming process includes cutting and forming, single-station single-click, double-click cold heading and multi-station automatic cold heading. Instead, the automatic cold heading machine itself cuts and upsets the rough (if necessary) from the bar and wire rod. Before extruding the cavity, the blank must be shaped. Through shaping, a blank that meets the process requirements can be obtained. Before upsetting, reduction and forward extrusion, the blank does not need to be shaped. After the blank is cut, it is sent to the upsetting and shaping station. This station can improve the quality of the blank, can reduce the forming force of the next station by 15-17%, and can prolong the life of the mold. The bolts can be manufactured with multiple diameter reduction.
Thread processing bolts The thread is generally cold processed, so that the thread blanks within a certain diameter range are passed through the threaded (rolling) wire plate (die), and the thread is formed by the pressure of the wire plate (rolling die). The plastic streamline of the threaded part is not cut, the strength is increased, the precision is high, and the quality is uniform, so it is widely used. In order to make the outer diameter of the thread of the final product, the required thread blank diameter is different, because it is limited by factors such as the accuracy of the thread and whether the material is coated or not. Rolling (rolling) threading refers to a processing method that uses plastic deformation to form thread teeth. It uses a rolling die with the same pitch and tooth profile as the thread being processed. While extruding the cylindrical screw blank, it rotates the screw blank and finally transfers the tooth shape on the rolling die to On the screw blank, the thread is formed. The common point of rolling (rubbing) thread processing is that the number of rolling revolutions does not need to be too much. If it is too much, the efficiency is low, and the thread tooth surface is prone to separation or random buckling. Conversely, if the number of revolutions is too small, the thread diameter is likely to be out of round, and the initial pressure of rolling will increase abnormally, which will shorten the life of the mold. Common defects of rolled threads: cracks or scratches on the surface of threaded parts; random buckles; threaded parts out of round. If these defects occur in large numbers, they will be discovered during the processing stage. If the number of occurrences is small, these defects will circulate to users without noticing the production process, causing trouble. Therefore, the key issues of processing conditions should be summarized, and these key factors should be controlled in the production process.