Analysis on the current situation of the hottest e

2022-07-30
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Analysis on the current situation of steel drums for export packaging

there are many types of steel drums for export packaging in China, most of which are between 15~200 liters in size, and two types of mouth are common, namely, full open and closed. The full opening barrel is sealed with a large cover and hoop, mainly containing solid and semi-solid; Closed end barrels are mostly used to hold grease and liquid

as the packaging of export commodities, the most used is of course the 200 liter steel barrel, which is called 53 gallon barrel in foreign countries. In the past decade, oil and other liquid raw materials have been filled with leakage from time to time. It is understood that although the barrel making technology and equipment have also been developing in recent years, the overall quality has not improved much. At present, few domestic 200 liter steel barrels can really pass the drop test without leakage. Therefore, solving the leakage problem of export steel drums has always been listed as the key research project of export containers. After investigation, it is found that the position and proportion of steel barrel leakage are roughly as follows: 10% at the barrel mouth and end; Barrel body welds account for 5%; The triangular area of crimping and welding seam accounts for 85%, and the triangular area is the most

269 in order to solve the problem of leakage, the following aspects should be taken into account:

1. advanced seam welding machines are used to reduce the width and thickness of seam welding overlap, which can greatly reduce seam welding leakage and curling leakage

at present, the steel drum seam welding machine used by most Chinese drum manufacturers is still a semi-automatic domestic machine, and the overlap of seam welding is mostly about 10mm. At the overlap welding part, the thickness of the material is about twice that of the plate. When this part is rolled and sealed, it is thicker than other parts, so there are often uncompacted gaps at the transition from thick to thin, so leakage occurs. In order to solve this problem, some barrel manufacturers have adopted a variety of improvement methods, and have made some progress. For example, the seam welding machine device of Tianjin Jingda dilute Co., Ltd. is improved on the original semi-automatic seam welding machine, which can not only improve the seam welding speed, but also have smaller overlap and thinner overlap thickness; Others use the edge roller to roll the lap edge after welding to thin the double-layer edge; The most advanced is the full-automatic seam welding machine. The welding lap width is only 2 ~ 4mm, and the welding quality can be fully guaranteed. At present, the more advanced technology abroad is the laser welding technology, which can realize the butt welding of steel plate, and its performance is more excellent

2. improve the crimping process, so that the crimping can reach seven layers and be rolled and compacted

ten years ago, the bottom and body of steel drums in China were all rectangular five layer hemming. In recent years, the seven layer round hemming technology abroad has been gradually popularized in China. Therefore, the problem of leakage in crimping is greatly reduced. However, the quality is endless. Today, the problem of curling leakage has become the key to seriously affect the development of steel barrel. From the technical point of view, there are several aspects of curling leakage:

⑴ insufficient curling level. This kind of situation is quite common, because many manufacturers have not really mastered this technology under the situation that the country has begun to engage in round crimping, but have just changed the groove type of the crimping roller to meet the requirements of users. This kind of round crimping is indeed round crimping from the appearance, but the real internal quality is not guaranteed. The most obvious difference is that the number of crimping layers does not reach seven at all, and some are only five. Therefore, the leakage of curling is inevitable. To solve this problem, it is necessary to carry out production according to the correct process of round crimping, which of course requires investment. At least, it is necessary to change the blanking size of the bottom and top of the barrel, so that the edge material of crimping is enough to cause enough damage to the sensor; In addition, it is necessary to add a pre roll glue sprayer at the bottom and top of the barrel, roll the edge of the bottom and top into a groove in advance and fill in the sealant before crimping and sealing; In addition, the flanging width of barrel body shall be increased accordingly. Only in this way can the seven layer curling be guaranteed

⑵ the crimping layer is not tight. Some steel drums have seven layers of curling, but the curling is not compact. Because there are cracks, leakage becomes a normal thing. The main reason for this is that the groove shape of the edging roller is incorrect or the pressing force of the roller is insufficient. The roller groove is the most critical technology in the crimping technology. Generally, only a few manufacturers have mastered it. Some manufacturers have not really mastered it. The quality is sometimes good and sometimes bad, and some still need to be further discussed. Because the process parameters, process methods and equipment of each manufacturer are different, the groove type and other parameters of the roller are also different. However, as long as you master the essentials of the design, you can adapt to the situation

⑶ uneven crimping size. Some steel drums produced by some manufacturers have uneven crimping size due to the influence of process quality, so there are gaps in some places. For example, the flanging size of the barrel body is not the same around, the seam welding overlap is too thick, and the thickness of raw materials is uneven. All these factors can cause gaps in crimping, which must be paid enough attention

3. the sealant to prevent leakage shall be strictly controlled. Unqualified sealant shall not be used, and shall be produced in strict accordance with the process without wet sealant

in the operation of steel drum curling and sealing, sealant must be sprayed to fill the gap of materials in the curling. However, the quality of some sealants is not good, and some curing components are too few, and there is a gap after the glue is dry; Some sealants are not resistant to high temperature. When the steel barrel is applied and dried in the drying furnace, the glue flows out of the curling gap; Some sealant fails after reacting with the goods in the steel barrel; Some seals have weak adhesive force and are extruded out of the crimping during crimping operation. Therefore, products with guaranteed quality must be selected for the edge curling sealant of steel barrel, otherwise the edge curling quality is difficult to be guaranteed

as required, the glue spraying operation must be carried out when the barrel bottom cover is pre-set, and can be used for curling after 24 hours of drying. Because the wet glue can not be sealed after being rolled into the crimping, and because it occupies the gap space, it cannot be solidified for a long time, and it is very easy to flow out after the steel drum is impacted, resulting in leakage, so the pre roll glue spraying process must strictly control the quality

4. the barrel mouth pressing process should pay special attention to quality, and the sealing should be tight and compact

in most cases of leakage at the barrel mouth, the up and down stroke limiting devices are caused by the problems of the barrel mouth stamping die. Leakage may occur due to die aging, dimensional change of barrel opening parts, quality problems of sealing ring, reaction between sealing ring and contents of steel barrel, etc. Therefore, stamping dies must be replaced regularly; It is necessary to purchase the barrel mouth parts from a unified supplier. If the supplier changes, the mold must be redesigned and manufactured; The sealing ring shall be complete and consistent in size; The user's cargo shall be studied to ensure that the material of the sealing ring will not react with the cargo and lose the seal. The power switch shall be turned on to allow the instrument to preheat for 20 minutes

some problems are often found in the use of export steel drums. There are mainly the following categories:

1. quality problems of internal coating barrel

some export commodities need to be internally coated with steel drums with full openings, or lined with polyethylene. Such steel drums are prone to leakage, and the barrel mouth must be padded. Some inner coated barrels are used to hold food, such as apple sauce, tomato sauce, honey, etc. because the inner coating does not meet the food hygiene requirements, the contents of the goods are polluted. Some have poor spraying quality, and the coating falls off seriously, resulting in rust on the inner surface of the barrel. Some do not use special sealant for food barrels, which also causes food contamination. These situations should not happen. As long as the quality is strictly controlled during production, the internal coating quality of the steel barrel can be guaranteed

2. structural problems of steel drums

steel drums filled with grease are often placed in the open air. Some end gaskets react with the contents and lose sealing effect, which is also prone to leakage; In rainy days, the loose bucket mouth is easy to water, which makes the grease sour and deteriorated. This may be caused by the unreasonable structure of our steel barrel at present, because the barrel mouth is lower than the outer edge of the barrel, so the accumulated water is easy to seep in. The international standard steel barrel structure is that the barrel mouth is higher than the barrel edge, so this situation will not occur. Therefore, to thoroughly solve this problem, we must implement international standards as soon as possible, introduce advanced technology, and change the unreasonable product structure

3. surface coating problem

the paint color on the surface of steel drums is generally black for oil, and blue, green, brown and other colors for chemical raw materials. However, the color of steel drums produced by steel drum manufacturers is always different, resulting in different colors of successive batches of steel drums, which has a great impact on foreign chemical products that pay attention to brand and packaging, and should be avoided as far as possible

it is understood that most of the reasons for this situation are the fault of the paint suppliers, who supply paint to the barrel factory by batch, but the colors of different batches are always different, which can not guarantee consistency. To solve this problem, it is necessary to establish a long-term fixed relationship with paint suppliers and strictly inspect and control the quality of paint. In addition, during the use of paint, try to mix evenly to make the paint color consistent

4. steel problem

it is a development trend in recent years to minimize the cost of export packaging steel drums. At present, many manufacturers use coil production, which really saves a lot of costs; In addition, the thinness of materials is also a way to save costs, but it should be enough, and it should be determined according to the process and technology of each company, so as not to cause new quality problems

in order to save costs, some manufacturers use 0.8mm steel plate to manufacture 200 liter steel drums. Of course, this is not impossible in one-time export packaging, but we must consider the actual needs of the goods inside. We must not use ultra-thin steel plates uniformly. In addition, some manufacturers use steel plates with uneven thickness or serious corrosion to manufacture steel drums, which also causes quality problems to varying degrees. I hope this situation will not happen again. (by yangwenliang)

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