Analysis of the triple circle of steel drum

Analysis of the triple circle of steel drum

Jiangxi Lefeng Metal Container Factory Zhong Taiqing

When Comrade Jiang Zemin, General Secretary of the CPC Central Committee visited the first industrial technology progress exhibition, he said: "Packaging is very important. It is not only a matter of protecting goods, but also increasing the added value by doing a good job of packaging. We must pay attention to the big problem of packaging. General Secretary Jiang’s remarks on the importance of “packaging this big problem”, which puts higher requirements on steel drum packaging to meet the needs of the rapid development of the domestic economy. .

In the international and domestic markets, 200 litre closed steel drums are a major form of packaging. Especially for the packaging of petrochemical products, it has a prominent position. The 200-liter closed steel drum is also a heavy-duty package, that is, the packaged product is directly injected at one time. It does not resemble a double-duty package, and it is protected by more than two types of packaging, such as a carton or wooden case after bottled. After packaging 200 liters of closed steel drums, the weight is above 150kg. In the process of storage and transportation, it is inevitable that there will be collisions and fall, all of which puts higher requirements on the quality of the inside and outside of the 200-liter closed steel drum. The International Maritime Dangerous Regulations set high standards for 200 litre closed steel drums to meet the needs of maritime transport safety.

The main “quality requirement” for a 200-liter closed steel drum should be said to be leakage. Leakage mainly comes from 1 uniform barrel mouth, weld seam and three parts of upper and lower curling. Judging from the nationwide inspection situation of the State Administration of Commodity Inspection and the inspection of the export packaging of various production plants, it is not too difficult to solve the leakage problem of the barrel mouth and the straight weld, as long as the process operation or some appropriate process is done. Correction can be solved. However, to solve the leakage problem of the upper and lower curls, especially to meet the Class I standard of the International Maritime Dangerous Regulations is not so simple. It can be said that the process of triple-layer and seven-layer crimping is not allowed.

As early as the 1970s, some of the more advanced countries in the world began to solve the problem of triple round curling. It can be said that the formulation of the International Maritime Dangerous Regulations refers to this factor, and the steel drum national standard also pays attention to this point. However, among the many 200-litre closed steel drum manufacturers in China, there are only a few factories that have truly solved the triple round crimping, especially the manufacturers that have stable production according to this process. Some manufacturers have solved this problem, but they have not achieved the effect of a true triple-layered seven-layer round curl. Many manufacturers are still in the sixth floor, so it is difficult to pass the "International Maritime Dangerous Standards" category I standard drop in the difficult.

Solving the problem of triple-layer and seven-layer round curling is a problem that manufacturers of 200-liter closed-mouth steel drums are forced to overcome, otherwise they will be eliminated. It is from this point that the author talks about some of the opinions he has accumulated in practice, in order to find the effect of throwing bricks and jade.

Excellent performance of one or three rounds

The pros and cons of performance are comparative. The excellent performance of the triple rounded edge is also compared with the double crimping (including round and rectangular). Both theoretically and practically, the double round bead has the following excellent performance conclusions:

1. Extremely high resistance to leakage.

The so-called triple round curling, that is, the barrel body and the top of the bucket, the curling has three sets of overlapping parts, and the head part of the top of the bucket, as shown in Fig. 1. In the figure, 1 and 2 are the first overlap, 3 and 4 are the second overlap, 5 and 6 are the third overlap, and 7 is the hook portion of the bucket top. The double curl has only two overlapping parts, one head part, that is, the third overlap is missing. It is not difficult to see that the triple rounded edge adds a key set of overlap for leak resistance. Since this group overlaps the portion where the filler is located, the impermeability is improved. Therefore, in theory, the impermeability of the triple round bead is far superior to the double bead.

Figure 1 crimping section

1, 2 - first overlap; 3, 4 - second overlap; 5, 6 - third overlap; 7 - hook

From the drop test, the partial curling at the moment of landing is subject to several tons of counter-impact, causing destructive deformation, as shown in Figure 2. It can be seen from the figure that the first overlap of the curled edge has been broken, but the triple seven-layer round curl still retains the second and third sets of overlaps and a hook, which still has a double crimp. Performance, still can play a good impermeability. Once the double curling edge has been dropped, the leakage is easily caused by the destruction of the first overlapping portion, leaving only the second overlapping portion and a hook.

Figure 2 Cross-sectional view of the fall

1-first overlap; 2-second overlap; 3-third overlap; 4-head

The author also confirmed this from a long period of practical observation. At present, the three-layer seven-layer round-edged 200-liter closed steel drum produced by our factory has not leaked from the height of more than 2 meters, or the same steel drum dropped three times from different angles. Our factory participated in the Class I standard test of the Central China Film Quality Regulations organized by the State Administration of Commodity Inspection. Although the barrels were not negligently passed, the six steel barrels in the 1.8-meter drop test were only hard and unambiguous. At the place, it fully proves the excellent anti-seepage performance of the triple seven-layer round curl. Double curling, do not talk about passing the Class I standard, that is, the Class II standard that falls through the height of 1.2 meters also depends on "luck". Here may wish to tell a joke, I did not press the three-layer seven-layer round curling process before production, please the comrades of the Commodity Inspection Bureau to test, but only to fall according to the Class II standard, then as the director of the factory I am fidgety, but also can not help Going to the scene, and afraid to hear the sound of the fall, I was so eager to ask God to bless my factory. However, God did not give face, did not bless us, and still failed. Today, our factory insists on organizing production according to the process of triple-layer and seven-layer round curling. The comrades of the Commodity Inspection Bureau came to our factory to test according to the Class I standard. Today I am very different, with the taste of a bird gun. I am sitting on the Diaoyutai and I am safe to deal with other things. At the end of the test, the comrades of the Commodity Inspection Bureau came to my office and seriously said that the fall did not pass. I didn't even hesitate to blurt out: "It is absolutely impossible!" The comrades of the Commodity Inspection Bureau also laughed and said that they did not expect the old clock to be so confident. My answer is also very simple: "Of course, we have a triple seven-layer round curl!". To be honest, God can't be blessed. Only three layers of seven-layer rounds can guarantee the smooth passage of the requirements of the International Maritime Dangerous Regulations.

2. High strength and excellent impact resistance.

As can be seen from the cross-section of the triple circle, the entire bead is almost a whole. It is like a round steel bar, and there is no local damage of the plate, that is, the occurrence of stress concentration is avoided. It goes without saying that its mechanical strength is high. Rectangular or triangular curling is just the opposite, and severe stress concentration occurs, and the local damage of the barrel is severe. Our factory used the same bucket to test from multiple heights of more than 2 meters and dropped it at different angles. The result is not only leaking, but also the process of partial damage. Not too big. This is only the effect of the triple seven-layer round curl side. The rectangular or triangular curling is likely to cause cracks after falling, which is the most unpleasant thing. In the normal storage and transportation process, especially the friction between the bottom of the barrel and the ground, the stress concentration of the rectangular or triangular curl is also very easy to break.

From the point of view of the anatomical curl, it is almost impossible to unfold the three-layer and seven-layer round curling edge, and it is very simple to unfold the double-sided rectangular curling layer. This is also a three-layer seven-layer round crimping edge with high strength and good impact resistance.

3. Triple round curling has a beautiful appearance

Squares and circles, in the human eye, the round shape is more beautiful, especially on the round 200-liter closed steel barrel. If it is fitted with two rectangular curls, it does give people an uncoordinated feeling. On the contrary, with two triple rounds, it gives people a beautiful appearance.

Two key processes for the formation of two rounds

The triple seven-layer circular crimping is a difficult problem in the barrel making technology. It cannot be broken by a single crimping process, but it may be formed under the cooperation of several processes.

1. Bottom forming of the bottom of the bucket and the cover

The size of the bottom of the bucket, the size of the lid and the size and uniformity of the formed crimping lid directly affect the quality of the crimp.

If the size of the barrel cover is too large, that is, the material is excessively cut, if the forming groove of the R wheel is taken to a larger size when the sealing groove is used, the steel barrel curl is loose and cannot reach the triple seven-layer circle. The purpose of crimping; if the forming groove of the R wheel is taken to a smaller size, the curling edge is extremely squeezed, which is not only detrimental to the production equipment, but also fails to achieve the desired crimping purpose. The curling edge formed is not round, and many dead corners are generated, which destroys the strength of the curling edge, and at the same time, a "spit tongue" phenomenon occurs.

The curling of the lid is too small, that is, the material is not defective, and the steel barrel is not formed with a hook part after forming, and the effect of triple and seven layers is not achieved.

If the size of the curling part in the bottom of the bucket and the cover is not uniform, the sealing J<wheel groove only adapts to a certain size. If the part exceeds this size, the deformation will occur, and the part smaller than this size will appear. Loose.

From the theoretical calculation and practice, it is known that the width of the bottom of the barrel and the edge of the cover is about 27 mm. In order to overcome the uneven size of the curled portion, the bottom forming of the bottom of the bucket and the lid are preferably completed in one operation.

2. Bottom of the bucket and the edge of the cover

The bottom of the bucket and the pre-bead of the cover can function as the hook portion of the pre-formed crimp and the fixing filler in an optimum position.

Some advanced countries in foreign countries have long used the hemming process. In 1986, when I visited the national-intermediate packaging exhibition held in Guangzhou, I found that the samples brought by a German company had been published. At that time, China's barrel industry could be said to be still blank.

Why do you say that the bottom of the bucket and the cover of the cover can play a role in the part of the hook? The reason is very simple. When the curling machine is formed on the crimping machine, after the barrel body and the bottom of the bucket and the cover are inserted into each other, the pressing force when the two sides of the template are pressed tightly, the top of the pulling edge portion of the barrel body is just pushed into the bottom of the bucket, and the cover is placed. The inner top of the curled edge. For example, the size of the side of the barrel and the size of the bottom of the barrel and the curl of the lid are appropriate. It can be said that the seventh layer in the curling edge, that is, the hook portion has already been formed.

After the bottom of the bucket and the cover are pre-rolled, the filler is continuously dropped during the rotation. By means of the centrifugal force of the rotation of the bottom of the bucket and the lid, the filling material just enters the bottom of the bucket and the inner top layer of the cover portion, which is used for the filling material. The best part of the action.

Practice has proved that the inner diameter of the bottom of the barrel and the edge of the lid is preferably Rlmm.

3. The choice of filler and pre-drip solidification.

In addition to the dissolution of the packaged product, the choice of filler should also take into account its plasticity after solidification, ie elasticity. It should be said that it is better to have good elasticity, and it is best not to use poor elasticity. This is the main reason for the elimination of brown sugar bone glue.

After the filler is injected into the inner cavity of the crimping, it should be fully cured to form a sealing ring, which acts as a filler. Due to the good sealing performance of the triple seven-layer round crimping, if the filler is uncured and formed by crimping, the filler is difficult to solidify and does not function as a seal. Once the drop test is carried out, the curling is broken and the filler flows out first, causing leakage. At present, there are a lot of crimping machine designs with filler nozzles, which are actually not suitable. Many manufacturers just use it as a display.

4. The edge of the barrel

The size, angle and uniformity of the barrel edge directly affect the formation of the triple round.

The size of the wrench is too large to insert the bottom and cover of the bucket that has been crimped. On the contrary, the barrel body will not be able to form the third layer of the curling edge, and the bottom of the barrel and the cover will appear self-biting in the curling edge.

The angle of the edge of the edge is preferably 100 degrees. In the process of crimping, by the extrusion of the template, the angle of the 90 degree can be achieved. At this point, the top end of the wrench edge just enters the bottom of the bucket and the inner top position of the cover to the bead. According to this requirement, it is not difficult to calculate the reasonable size of the edge portion.

The uniformity of the size and angle of the edge portion affects the quality of the bead as well as the size of the bottom of the barrel and the portion of the cover. The author believes that the squeeze-type edge-trimming process can achieve better results. Of course, the hot rolled sheet material is easily broken, but it is necessary to pay attention to the problem of consistency.

It is worth mentioning that after the barrel is pulled, the wrench part will be deformed for various reasons. After this condition, it must be repaired before the curling is formed. Otherwise, it will be difficult to reach the triple seven-layer round curl. the goal of.

5. Crimping seal

The formation of the triple rounded edge finally looks at the process of crimping the seam. Some people think that this is the most crucial level. On the surface, it seems quite reasonable, but it is not. The author believes that: the first few processes are handled properly, then the crimping is just a routine "business".

In the barrel industry, the crimping machines currently used are similar, and the principles are the same. Most of them also use two R wheels. The R wheel is the key, and the R slot on the R wheel is the key. What is the size of the R slot? It is difficult to draw conclusions. This depends on the customary factors of each plant, such as the texture of the materials used. Bucket body, bottom, cover blanks, etc. But there is one: the front R wheel is formed, the rear R wheel is compacted; the front R wheel is loose, the rear R wheel is tight; the front R wheel groove is larger in size, and the rear R wheel groove is smaller in size but consistent.

The author believes that the processing of the above several key processes, triple seven-layer round curling is achievable. Although the factory is an insignificant small factory, it is just doing this, and has formed a stable process specification for this production.

Third, the end of the view

1. Raw materials (mainly barrel steel and filler) have a great influence on the formation of triple seven-layer round crimps. In particular, the thickness of the steel sheet for the barrel can directly lead to the success or failure of the triple round. Practice has proved that the imported plate standards are better mastered, while the domestic plate, especially the hot-rolled plate, is very different, which brings great difficulty to the production of triple-layer and seven-layer round crimping, and even can not be a stable production process. . Suggestions for improvement should be made to steel manufacturers.

2. After the formation of the triple seven-layer round curl, is it up to standard? It is impossible to do only a destructive drop experiment, and it is even more impossible to dissect only. The author has found a set of visual inspection methods from many years of practice, which is almost 100% accurate.

First, the outer diameter of the bead is measured. Generally, the outer diameter of the rounded edge is φ8±0.2, which is the most reasonable.

The second is to detect the height of the barrel. The height and size are related to the size of the barrel. The manufacturers are different. However, the standard size can be calculated according to the size of the blanking.

3. The triple seven-layer round curling edge does have many excellent properties. From the national barrel manufacturers, there are indeed some factories that have broken through this difficulty. But it must be pointed out that some manufacturers have not really achieved the goal of triple-seven layers, and some have only taken a few samples and have not formed production capacity. These are all dangerous signals that should be highly valued by their peers.

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