Influence of the size of steel drum sealing process on the quality of the sealing

Yang Wenliang Xin Qiaojuan

With the development of the market economy, consumers are increasingly demanding the quality of steel drums. In order to reduce costs, the trend of thinning steel drums has become more and more obvious. Recently, many companies have reported that users demand more and more 200-liter steel drums with 0.6-0.8mm steel, so there are many contradictions. Since the process size has not been changed in time, the quality of the hemming is difficult to guarantee. There are many technicians in the enterprise who do not fully understand the inconsistency of the process size after the material is thinned. It is erroneously considered that as long as the size of the roll-up roller groove is changed, the manpower and material resources are unsatisfactory, and the result is unsatisfactory. This article discusses the current problems in the domestic barrel industry, in order to attract attention.

First, the relationship between the sealing process and materials

How many layers can the roll-up process roll? Some people think that the more and more, this is true! The more the number of curling layers, the higher the strength and the better the sealing effect. However, is it possible to achieve ten-layer and twenty-layer seals? Here we do not say that there is a quality cost problem, in fact, this is not possible. Even if the roller groove design is better, it cannot be achieved. Why?

1. Restrictions on steel drum raw materials

We make steel drums that require low carbon content and good plasticity. Because the processing performance is very good, welding, stamping, and bulging are all easy to ensure quality. However, the curling is different, because the size of the crimping roll groove is unlikely to change with the crimping process, and the crimping force is gradually transmitted to the center of the curling edge through the peripheral material to wind the center. The better the plasticity of the material, the more difficult it is to transmit. We can imagine that if the material of the steel drum is made of spring steel and the same material as the clock of the clock, don't say that the ten layers are rolled. I am afraid that it is easy to be twenty layers because it is elastic and rigid, and the sealing force is passed through the periphery. It is easy to pass to the center. However, this is impossible because the material has good elasticity. Therefore, when the sealing force disappears after the winding is completed, it is easy to bounce back to the original state, that is, to return to the beginning of the winding. This is obviously not what we need. Therefore, it is impossible for us to use highly elastic materials. Judging from the materials used to make steel drums all over the world, China's materials are the most rigid, so the quality is difficult to guarantee. Moreover, the number of curling layers does not exceed seven layers. According to the research of foreign experts, the number of layers of steel barrels will not exceed seven, and it is obvious that the sealing force is not transmitted so far.

2. Restriction of steel drum sealing process

At present, the most advanced sealing technology in the world is similar, which is different from the change of the curling groove type and the winding speed. This process is the most economical method for mass production and the lowest cost method. If you don't care about these, there may be a better way to make the curling force go further and make the curling more than seven layers. However, for the steel drum product, it is enough to be able to achieve a good seven-layer crimping. If the quality of the current sealing is not good, then look for other problems.

Second, the relationship between process size and the number of layers

This is actually a simple question. Many people have discussed it before. I don't want to explain it through boring theoretical calculations. We all know that if you want to roll seven layers, you have to have seven layers of things. That is to say, the side width of the bottom cover of the bucket and the size of the flange of the bucket are sufficient. Because the process size is insufficient when the material thickness is determined, it is impossible to roll up to the seven layers. So is this the more the process size is the better? Not also! Imagine that the curling can only be rolled up to seven layers. Do you want extra materials to go there? Either increase the bead size, the result may be seven layers, but the internal clearance is large; or excess material is squeezed out of the roller, causing the iron tongue. In short, the quality of the curling is not guaranteed. Therefore, the process size of the crimping must be determined, not too much or too little, this is the best.

Third, the relationship between the size of the steel drum and the size of the crimping process

What I want to say here is that the size of the steel drum has nothing to do with the size of the crimping process! Then why should you write this question, because many friends of the company believe that the larger the steel drum (the diameter), the larger the width and the flange of the bottom of the steel drum, which is wrong. This is the main reason why the quality of the curling is not good after the steel drum is thinned! I have already said that, I will not repeat it here. I just emphasize that if the thickness of your material changes, to get the best sealing effect, you need to change the process size. Because the reasonable crimping process size is only related to the thickness of the material!

Fourth, consider multiple factors, determine the method of crimping

Often things don't always follow people's wishes, and the users that the barrel-making companies are now encountering are really strange. In fact, it is these difficult users that we have the development of the barrel industry. The user is our food and clothing parents, his needs are our willingness. Take our 200-liter steel drum. It used to be made of 1.25mm material for many years. Now some users have to use 1.0mm, some have to use 0.8mm, and now there are people who need 0.6mm of material, barrel It is impossible for the factory to eat and not to do it.

However, the problem has come out, the material is thin, and it is not enough to say that the manufacturing process is difficult. It is annoying to seal the item alone. Because the material is thin, it has to be rolled into seven layers. Obviously, the original process size is large, and it is impossible to obtain a good seal quality without changing the process size. If you use a process size of 1.0mm to make a 0.8mm steel drum, the problem is not so obvious. Sometimes it is okay to pass the customs. Although the quality is not very good, it can always pass. However, some enterprises use the original 1.25mm process size to manufacture 0.6mm steel drums. The contradiction is very obvious. It is not feasible without solving it.

In general, barrel companies are reluctant to change the process size of the crimping, because changing the process size means reopening a set of bottom molds. The size of the flange is easy to solve, but the cost of a set of molds is considerable. If the batch size is not big, no one is willing to do it.

As far as the actual situation in China is concerned, there is only one solution, which is to change the original circular curl to a flat curl. Because the material is thin, the process size of the bottom cover is large, and there are certainly a lot of voids in the curling, and the quality is difficult to guarantee. In order to get the curled edge and not want to change the mold, it is the best way to flatten the curl. Most of the domestic manufacturers of 0.6-0.8mm 200-liter steel drums have been changed to flat crimping, including thin-walled tapered drums. Of course, this is only a matter of expediency. If the production of thin-walled barrels is large enough (this is the direction of development), opening a set of bottom-bottom molds should be the best choice.

It seems that I am teaching others how to make or fool people. In fact, people in the barrel industry know that sometimes there is no way to do things. It is a good idea to have a stupid way to put things in order. For most SMEs, the variety of products is unpredictable. In order to occupy that poor market, to win a bowl of rice to eat, what kind of barrels are willing to do, so there are more contradictions. Several large domestic barrel factories have been doing a single product for many years and are unwilling to dry up the barrels. Those small and medium-sized enterprises that fill the gap in the market have become the chores and supporting roles in the barrel industry.