Process of steel barrel quality (IV)
2. Weld perforation
when there is perforation at the seam welding position, the seam welding directly produces leakage, which is a waste product of this process, and can only be repaired by means of repair welding, and can only be treated as defective products after repair. If the perforation is in the medical care position of the flanging part, it will be more difficult to repair, which will easily affect the subsequent process, and it cannot be repaired if it is serious.
3. False welding at the seam welding position
false welding is the most dangerous, because it is sometimes difficult to find. Some false welds have leakage in the leakage detection test, and some false welds do not leak at that time, but it is easy to leak when the steel barrel is collided in use. Because the false welding is not welded or not completely welded, the welding strength is certainly unreliable, and it is also easy to have problems in the subsequent process, such as cracking during flanging; It is also easy to crack when expanding reinforcement, which can be found in time. However, if the steel drum with false welding is allowed to leave the factory, the hidden danger is quite serious
4. Charring of weld seam
charring of weld seam can cause the material at the weld seam to harden and become brittle, which is very easy to produce cracks at the stress concentration in the process of subsequent flanging and expanding reinforcement, and it will also be difficult to form due to brittleness in the process of flanging and sealing. In addition, the problem of cracks can also cause leakage problems at the flanging part that are difficult to repair. V. barrel flanging process problem
barrel flanging is the most important process affecting the quality of sealing. First of all, it is necessary to determine the process requirements and technical standards of flanging. If the process requirements and technical standards are not formulated scientifically, it is impossible to make qualified products.
the common quality problems in flanging process are over tolerance of flanging size, over tolerance of flanging angle, uneven flanging, mechanical damage, flanging crack, etc.
1. The flanging size is out of tolerance
the flanging size is out of tolerance, mostly because the width cannot reach the required size, which has an obvious impact on the flanging process. Due to the lack of flanging materials, it is certainly difficult to achieve the ideal number of layers, and voids will also be formed in the flanging, resulting in leakage.
there are few cases of excessive flanging width, but if this happens, it will have a greater impact on the quality of flanging, because the flanging edge may be too wide to be included in the pre flanging edge of the barrel bottom cover during the flanging assembly, and the barrel bottom cover will roll itself during the sealing process, which is often said to be one of the fake cases of ASTM d3702 ⑼ 4 thrust ring experimental method for measuring the friction performance of materials, The result is often that the bottom of the finished barrel is easily separated from the barrel, which is the most serious quality problem of the steel barrel and must not occur!
2. The flanging angle is out of tolerance
the most exquisite flanging process is the flanging angle. Generally speaking, 90 ° flanging is the most ideal. In fact, this is really just an ideal. In practice, forming a flare shaped flanging is the best way to ensure the quality of the flanging process. Generally speaking, the included angle between flanging and barrel body is 105 ° ~ 110 °, which is mainly due to the following reasons:
the included angle of 90 ° is often deformed due to collision in the process of process turnover, so that the angle of some parts is less than 90 °. In the process of flanging and sealing, the flanging edge cannot be closely combined with the bottom edge of the barrel, which is prone to false roll quality problems; Even if there is no collision and deformation, when the verticality of the guide rod is 1/1000 on the bottom surface of the main base for crimping, sealing and adjusting, due to the pressure of the clamping discs on both sides, the reverse side of the 90 ° flanging is often tilted, forming an angle of less than 90 °, resulting in a whole circle of false curling. However, the angle greater than 90 ° is not easy to damage and deform in collision, and can be closely combined with the bottom edge of the barrel under the action of the sealing pressure plate, so as to achieve more reliable sealing and avoid false rolling. (to be continued)
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