Analysis of Quality Problems in Drum Delta of Steel Drum(1)
The enemy of the quality of steel drum products is leakage, because it makes the steel bucket lose its most basic function, so the leakage has become the topic most discussed by people. However, leakage is not a simple problem. Dedicated. This article attempts to conduct a special study on the quality issues of the steel drum seal triangle with the highest occurrence of leakage, in order to gain the consensus of experts and find a way to solve the problem in order to improve product quality.
The triangular zone of the steel drum refers to a special area where the barrel weld joint intersects the bottom of the barrel and the top curling seal*, and this area has become an area of ​​many accidents. Mainly because of its dual nature of seam welding and crimping, it brings together a variety of quality issues including seam welding problems, curling problems and interference issues, which is the main reason why it has long plagued the barrel makers.
In order to clarify our thoughts with the most clear and clear thoughts, we will discuss the quality issues of the triangle. We will follow the traditional analysis methods for each question we propose. That is to first put forward the appearance of quality problems and then analyze them. The cause of the quality problem, and then propose ways to solve the problem. I think that some people have already talked about the issue again, so I don't have to discuss it in detail. This article focuses on the regularity and systematicness of the problem.
First, the impact of raw material quality - crimp edge
For the study of quality problems in the triangle area, our usual analysis method is to cut the edge of the analysis to observe the shape of the cross section.
Sometimes, we cut the seepage section of the triangular section along the central curled section, and we see the situation as shown in Fig. 1. The leak is caused by one or more cracks in the curled part of the barrel.
Crimping seams are sometimes associated with welding (discussed in detail later), but we have found that under the same welding conditions, some materials will appear in large quantities in this phenomenon. After analysis and analysis, it is confirmed that it belongs to the material itself.
The materials used for steel drums have a very close relationship with the quality of steel drums. During the forming process of the steel drum, the deformation of the steel plate is stretched to varying degrees, and its internal stress is mainly tensile stress. When the internal stress of the deformed part exceeds the breaking strength of the material, the steel plate will break. Therefore, the steel plate is required to have good plasticity. The plasticity of the steel plate is related to the carbon content. The steel plate with low carbon content has good plasticity. Table 1 lists the chemical composition and properties of 200-gallon steel drums.
Table 1 Performance requirements of commonly used 200-liter steel drums
Steel number
chemical composition(%)
Physical properties
Technology
performance
C
Si
Mn
P
S
Tensile strength N/mm2
Elongation%
Stamping depth mm
08
0.05~
0.12
0.17~
0.37
0.35~
0.65
<
0.035
<0.040
275~
410
25
10.4
Δ1.25
10
0.07~
0.14
0.17~
0.37
0.35~
0.65
<
0.035
<0.040
295~
430
twenty four
11.0
Δ1.5
Due to the thicker materials outside seam seams, the amount of deformation during crimping is larger and more inhomogeneous than elsewhere, so if the carbon content of the material exceeds the limit, cracking will occur. In the production process, materials that frequently appear to have large quantities of flanging and edge cracking are mostly from steel plates imported from Russia and the United States, or some heavily corroded steel plates. This is rarely the case with domestic materials and Japanese imports. Therefore, in mass production, in order to meet the production process requirements of steel drums, high quality and stable steel plates should be selected to meet the deformation requirements of the drum crimping process.