Analysis of material and process problems affecting the quality of steel drums (1)

The main quality problem of steel drums is the leakage of steel drums, which is the key to the qualification of steel drums and the key to technology and technology. This is the focus of our research.

There are many process problems affecting the quality of steel drums. If they are searched and analyzed individually, they will only see the trees not seeing the forest, which is not conducive to the solution of the problem. Through long-term practice and research in the steel barrel industry from technology to production, we have discovered that these technologies and processes have internal relationships that affect each other, are unified, and are interconnected. Therefore, we must conduct a full range of interactive analysis. Only in this way can we find the essence of the quality problem and achieve the unification of technology, process, and quality.

With the process interaction impact analysis method, we can see the impact of each process on the quality of the steel drum production process, how it will affect, and how it will not affect or reduce the impact. Because most of the process problems at first sight do not directly affect the final quality, but using interactive impact analysis, it will find that it will have a certain impact on other processes, thus affecting the final product quality.

Drum production technology is actually a comprehensive technology. Production seems simple, but the technical field involved is very extensive. For example, the unwinding leveling of coils belongs to rolling steel shaping technology; barrel body material grinding (or milling) belongs to metal cutting technology; bucket body rolling and so on belongs to sheet metal processing technology; spot welding and seam welding belong to welding technology; The essence of the sealing technology; the bottom of the barrel and the barrel mouth of the production process are cold stamping technology; barrel body degreasing and rust removal is a chemical surface treatment technology; steel barrels of various methods of painting is a metal surface coating technology; The drying process of the coating film belongs to far-infrared heating technology and other heating technologies; the pattern production on the finished steel drum belongs to the printing technology category, etc.. Among them, rolling technology, forging technology, and hydraulic transmission are also used. Technology, pneumatic transmission technology, bulging technology, automatic control technology, etc. Therefore, barrelmaking technology is not a separate discipline. We must relax our eyes and study it carefully.

Now, let us use the cross-impact analysis method to carry out the necessary analysis of the main process. Due to the space, we can't elaborate on the process. We focus on the analytical methods and the interrelationships of the relationships, in order to play a leading role. The role.

First, raw materials affect the quality of the process

In order to ensure product quality, we must first ensure the quality of the process, and to meet the quality requirements of the process, the quality of raw materials to bear the brunt.

The main raw material of the steel drum is the steel plate, and the auxiliary materials include sealant, gasket, barrel mouth piece and paint and so on. The most important material affecting the quality of the process is steel.

The requirements of the steelmaking process for the steel plate are generally smooth surface, low hardness (small rigidity), small carbon content, and uniform thickness. Of course, what is the most appropriate, this is related to the conditions of the equipment of various manufacturers, there is also a quality cost problem, so you can not blindly seek high. As long as the minimum process requirements can be achieved. In the following, we analyze the problems that often arise when the raw material steel plate is not suitable for the barrel making process in the production practice.

1, the uneven surface of the steel plate

When the surface of the steel plate is warped unevenly, the size of the barrel may be unacceptable. After the welding, there may be cases where the two ends have inconsistent diameters or misaligned seams.

When the diameter of the barrel is small, the joint is affected when it is sealed with the bottom of the barrel, and the amount of barrel pressed into the bottom of the barrel cannot be in place, resulting in quality problems such as insufficient hemming material and false crimping.

When the diameter of the barrel is too large, the top of the barrel is loosely fitted during the roll-sealing, and the gap is too large and the sealing is not strict and the barrel body is wrinkled, resulting in leakage or surface quality problems.

Dislocation of the welding seams causes the edge-to-edge part to have a ladder-like flanging phenomenon in the flanging process. The lack of flanging at the short edge of the overlap edge affects the material shortage and the number of layers of the crimping process. Unreal quality problems.

When the surface of the steel plate is warped unevenly, the quality of the blank forming at the top of the bottom of the bucket is difficult to guarantee, and warping of the top of the bottom of the bucket may occur, and the degree of lamination in the top seal may be affected. The uneven warping of the open top lids causes problems with the assembly. Due to the effect of blanking roundness, uneven four-sided flanges may also occur, which may also affect the quality of the closed barrel and the sealing joint of the open barrel lid, which can cause leakage of the steel barrel.

2, steel plate hardness, rigidity

The hardness of the steel plate is high, and the rigidity is mostly caused by the large amount of carbon and heat treatment is not in place. For barrel making processability, it directly affects the quality of process forming.

When the hardness is too high, the rebound of the steel plate is large, and the radius of curvature of the steel plate is too large, which affects the position of the seam welding in the next process. In the process of the flange, the rebound is too large and the angle of the flange can be increased. It is too large and the size is reduced; the seaming process will also cause cracks in the curling due to the rebound problem, and there will be false quality problems.

Because of the large rebound, the quality of the locking of the mouthpiece on the drum cover will also be affected, and leakage may occur in the gap.

3, steel carbon content

Too much carbon in the steel will lead to high hardness and high rigidity. In addition, the high carbon content will have a great impact on the quality of barrel seam welding, making the welded part of the material brittle, cracking in the process of the latter flanging and bulging, which is the quality of the leakage problem of the steel drum The biggest hidden danger.

4, uneven thickness of steel plate

Uneven plate thickness is a taboo for barrel production.

Uneven plate thickness, seam welder will be at a loss, because the seam welder in the production of the first adjustment of various parameters have been determined, when the production of steel plate suddenly appears thin and thick, its parameters will not automatically adapt, so the emergence of welding Quality problems, we must burn it, and we must not solder it.

The uneven thickness of the steel sheet is more problematic in hemming assembly because a shaped hemming roller can only accommodate one thickness of steel plate. For ultra-thick steel plates, because the roll grooves are small and cannot be installed; for ultra-thin steel plates, because the roll grooves are large and dissatisfied, these two conditions will certainly cause more leakage.

The thin thickness of the steel plate is not suitable for the stamping process of the barrel pieces, which may cause the workpiece size to be out of tolerance or deformed, and may also cause the damage of the tooling die or the reduction of the service life.

5. Effect of auxiliary materials on process quality

Inappropriate auxiliary materials are sometimes an important part of the process quality of the drum.

The crimp sealant requires better elasticity, greater adhesive force, more solidified components, better chemical resistance, and better process performance.

The elasticity is good, so that it can have a certain amount of compression under the effect of the roll sealing force when the roll is sealed. Because of its good elasticity, it has a certain rebound force. With this resilience, it can squeeze the curled edge and improve it. Sealing performance.

With strong adhesive force, the apron pre-sprayed on the top edge of the bottom of the bucket can be firmly adhered to the curling edge, and it is not easy to fall off when the external force rubs against the flange of the barrel.

Most of the solidification components are for the purpose of truly filling the seam gaps, some of the glue curing components are too small, and the wet glue is sprayed on a lot, but after curing, the filling effect is not achieved.

Good chemical resistance is to prevent the sealant from adversely reacting with the contents of the drum, and some reactions can cause the sealant to fail, and some reactions may deteriorate the contents.

Process performance is good, mainly refers to the construction process, some sealant, other properties are good, but the construction performance is not good, if not easy to spray, brush, dry, etc., will cause difficulties in construction, thereby affecting the use; some plastic in the steel drum When entering the drying oven to dry the paint film, there are phenomena such as scorching and dilute flow, which affects the sealing performance of the crimp.

The sealing gaskets on the mouthpieces have a certain degree of elasticity that can make the sealing performance better. The chemical resistance of the materials is also very important, the same requirements as the sealant are mainly to prevent the gaskets from reacting with the contents of the gasket. Corrosion affects its sealability or contamination of contents.

The quality of the mouthpiece itself will also affect the sealing performance and interchangeability of the drum.

Drum outer coating only affects the quality of the appearance, but it has the greatest impact on the safety of the contents for the inner coating of the inner barrel. The adhesion and chemical resistance of the coating are the most important, and the processability determines the difficulty of construction and the effect of coating. If the quality requirements of the inner coating cannot be met, it will undoubtedly cause damage to the contents.