Analysis of barrel flange cracking quality issues (3)

Fourth, the flanging process quality problems

The final process that affects flanging quality is the flanging process, which is also one of the most important processes. At present, in the steel barrel manufacturing production line of the domestic barrel industry, there are roughly two kinds of process methods for the flanging process: one is for roll-over; the other is for mold flanging. Although the two flanging methods are different, the results are basically the same. For the material at the flanging position, it belongs to the deformation of thinning and stretching. In addition to the other reasons for the above analysis, the main influence on the quality is the process technology of the flanging process. Analyzed from the actual production point of view, the edge cracking is related to the angle of the flange, the arc degree, and the speed of the flange.

According to different steel drum production lines, some require that the angle of flanging (the angle of the flanging part and the barrel body) be 90° (that is, vertical flanging), and some requirements are greater than 90° (such as 95° or 100). Wait). In comparison, the larger the angle of flanging, the smaller the diameter of the edge of the flanging, the smaller the relative deformation, and it is not easy to break when flanging; while the vertical flanging, the diameter of the flanging edge is the largest, and the deformation is also the largest. It is easy to produce cracks. As for the steel drum manufacturing process, many crimping machines require that the lid and the barrel be pressed together before the tape is sealed. In order to tighten the barrel, the flange can be tighter with the lid. Generally, Flanging too straight (90°) is unfavorable. The relatively large angle of the flanging is more beneficial to the edge of the flanging and the lid.

The connecting part between the barrel body and the turning part after the burring generally has an excessive arc, and the radius of this arc is sometimes the main factor that causes the bluff crack. The greater the radius of the arc, the more relaxed the deformation force, relatively prolonged the deformation time, which is conducive to the uniform transfer of the flange force, the fracture is not easy to occur; if the radius of the arc is too small, the deformation suddenly occurs, the deformation force is not transmitted quickly, deformation If the time is too short, rupture can easily occur. In production practice, the problem of flanging caused by this reason is more and must be taken seriously.

The time for the flanging process is also one of the factors that affect flanging. Some manufacturers' equipment is die stamping and flanging, the process is fast, the deformation time is short, deformation force transmission is not urgent, and cracking is more likely to occur; some equipment is the use of hydraulic transmission mold flange, due to the relatively slow hydraulic speed, Power transmission is softer, so the possibility of cracking is much less; there are also some devices, especially some old ones, which use roll-over and flanging methods. The flanging process is the slowest among various flanging methods. Although the productivity is low, because the flanging force is transmitted slowly, like the double-acting press stretching, the possibility of cracking is very small. In the same material and in the case of the previous process, the rolling flange causes the least cracking.