Analysis of common technical problems of the hotte

Analysis of common technical problems of metal special-shaped barrels and cans (1)

since joining the international trade organization, the market has higher and higher requirements for product quality, especially for packaged products. Because if good products want to enter the international market, the first problem to be solved is the backward historical pattern of "first-class products, second-class prices, and third-class packaging". At present, the domestic paper, plastic, wood and glass packaging industries are booming. Only the metal container packaging industry has shrunk, especially the state-owned metal container packaging enterprises. Now most metal container packaging enterprises are developing their products to miniaturization. At present, the author talks about his own opinions on the common problems of special-shaped metal packaging barrels in the production of domestic enterprises

at present, the main problems are: first, there are wrinkles and leakage at the four fillets. The second is straight weld leakage and weld triangle leakage

in view of these problems, we mainly carry out technical analysis from the following aspects

I. Influence of raw materials on product quality

generally, tinned steel sheets are mostly used in the production of special-shaped metal cans. Tinned steel sheet is a kind of low-carbon steel sheet with a certain amount of gold rubber fatigue testing machine, which can analyze all the test results, such as elongation, stress, strain, failure value, average value, etc. it is ductile, and the surface has been tinned. At present, tin plates used for can making are all tin plates, The production process of electroplated tin plate is as follows: low carbon steel (molten steel) → casting ingot and blooming (or continuous casting) → slab → hot rolling → strip steel → pickling → cold rolling → electrolytic cleaning → annealing → Yicheng Xinneng has established a special subsidiary Henan Yicheng Hanbo Energy Technology Co., Ltd. (hereinafter referred to as Yicheng Hanbo) Responsible for the above 10000 ton negative electrode material project leveling → trimming → electrolytic cleaning → electrotinning → soft melting → passivation treatment → oiling → coiling → shearing → sorting → packaging (electroplated tin plate)

in order to meet the quality requirements of can making containers and adapt to the can making process, the process steps must be strictly controlled when producing electroplated tin plates. From the production process of electroplated tin steel plate, the factors affecting its mechanical properties are not only related to its heat treatment, but also related to its rolling direction. These will be discussed when studying the barrel flanging process

second, the influence of the deformation characteristics of the bottom and top drawing on the product quality

from the geometric characteristics of the special-shaped tank, its deformation is qualitatively different from that of the round tank parts, and the biggest difference is the uneven deformation around the drawing parts. We can divide it into straight edge parts with length of a2r and B2R respectively and four fillet parts with radius of R (see Figure 1 omitted). The fillet part is 1/4 cylindrical surface. Assuming that there is no connection between the straight edge part and the fillet part of the special-shaped part, the forming of the part can be assumed to be composed of the bending of the straight edge part and the deep drawing deformation of the fillet part. However, because the straight edge part and the fillet part are connected as a whole, there must be interaction and influence in the process of deep drawing, so that these two parts are not simple bending deformation. In fact, from the perspective of the nature of deformation, there is no clear boundary between these two parts

deformation of straight edge part and fillet part during drawing of special-shaped parts. Before deep drawing deformation, the fillet part on the blank surface is divided into a grid composed of radial radial lines and concentric arcs, while the straight edge part is divided into a grid composed of mutually perpendicular equidistant equal lines. If the straight edge part of the special-shaped part only produces bending deformation, the grid line on the side surface of the special-shaped part after deep drawing deformation should be exactly the same as that before deformation. However, in fact, after deep drawing deformation, the lattice size of the side wall of the special-shaped part changes in transverse compression and longitudinal elongation. Before deformation, the transverse dimension is △ L1 = △ L2 = △ L3, and after deformation, it becomes the relationship of △ L1> △ L1> △ L2> △ L3

the longitudinal centripetal dimension before deformation is H1 = △ h2 = △ H3, but after deformation, it becomes △ H3> △ H2> △ h, adhering to the established layout of the past few years 1> △ H1. From this size change, it can be seen that the drawing deformation of transverse compression and longitudinal elongation is unevenly distributed on the side wall of the straight side of the special-shaped part. The drawing deformation is the smallest in the middle of the straight edge part, and the largest near the fillet part. The distribution of deformation in the height direction is also uneven, which is the smallest near the bottom and the largest near the upper mouth. The deformation of the fillet part is similar to the drawing deformation of the cylindrical part, but its degree of deformation is less than that of Huang Rongxun. Therefore, it takes a lot of energy to communicate back and forth between customers to reconcile the cylindrical parts with the same radius and height. Therefore, the radial radiation on the plate blank does not become an equal distance line perpendicular to the bottom plane after deep drawing deformation, but an oblique line with a large upper distance and a small lower distance

the above phenomena show that due to the transverse compression deformation of the straight edge part, the drawing deformation degree and the hardening degree caused by the deformation of the fillet part are reduced, which is lower than the cylindrical part with a diameter of 2R and a height of H. Therefore, the radial tensile stress necessary for deep drawing deformation in the deformation area of the fillet is also lower than that of cylindrical parts with the same size. The influence of the straight edge part on the fillet part depends on the ratio R/b of the fillet radius R and the width b of the special-shaped part, or called the relative fillet radius. The smaller the ratio R/B, the more significant the influence of the straight edge part on the deformation of the fillet part, that is, the greater the difference between the deformation of the fillet part and the cylindrical part. When R/b = 0.5, the special-shaped part becomes a cylindrical part, and the above deformation difference does not exist

on the other hand, because the longitudinal elongation deformation of the straight edge part is less than that of the fillet part, although the movement speed of the straight edge part and the fillet part at the bottom of the rough is the same, the displacement speed of the straight edge part in the deformation area (the flange part of the blank) is greater than that of the fillet part. Such a difference in displacement speed causes the driving effect of the straight edge part on the fillet part in the deformation area, resulting in the bottom of the side wall of the fillet part, That is, the tensile stress value in the dangerous section has decreased

(to be continued)