Analysis of Quality Problems in Steel Barrel Sealing Triangle Area (1)

Analysis of Quality Problems in Steel Barrel Sealing Triangle Area (1)

Yang Wenliang

The enemy of the quality of steel drum products is leakage, because it makes the steel drum lose its most basic function, so leakage has become the most discussed topic, but leakage is not a simple problem, it is impossible Just do it. This article attempts to conduct a special study on the quality problem of the steel drum sealing triangle area with the highest leakage rate, in order to obtain the consensus of experts and find a way to solve the problem in order to improve product quality.

The triangle area of ​​the steel barrel refers to the special area where the barrel weld is intersecting with the bottom of the barrel and the top sealing edge. This area has become an area of ​​trouble. Mainly because of its dual characteristics of seam welding and crimping, it brings together various quality problems including seam welding problems, curling problems and interference problems, which is the main reason why it has long plagued barrel makers.

In order to clarify our thoughts with as clear and clear thoughts as possible, below, we will classify and discuss the quality problems of the triangle area. Every time we ask a question, we follow the traditional analysis method, which is to first propose the appearance of the quality problem, and then analyze The cause of the quality problem, and then the way to solve the problem. I think that some of the questions that have been discussed and discussed by people, I do not have to discuss in detail, this article focuses on the regularity and systemic nature of the problem.

First, the impact of raw material quality - curling edge

For the study of the quality problems in the triangular zone, our usual analysis method is to cut the crimping and observe the cross-sectional shape.

Sometimes, we cut the leaking part of the triangle along the center of the crimping section, and we will see the situation shown in Figure 1. Leakage is caused by the presence of one or more cracks in the curled portion of the barrel.

Figure 1 crimping gap

The crimping crack is sometimes related to welding (discussed in detail later), but we have found that under the same welding conditions, some materials will appear in large quantities, and after analysis and testing, it is confirmed that it is a material problem of the material itself.

The material used in the steel drum has a very close relationship with the quality of the steel drum. During the forming process of the steel barrel, the steel plate of the deformed part is stretched to different extents, and the internal stress is mainly tensile stress. When the internal stress of the deformation site exceeds the breaking strength of the material, the steel plate will rupture. Therefore, the steel sheet is required to have good plasticity. The plasticity of the steel plate is related to the carbon content, and the steel with a low carbon content has good plasticity. Table 1 lists the chemical composition and properties of steel plates commonly used in 200 liter steel drums.

Table 1 Performance requirements of common steel plates for 200 liter steel drums

Steel number

chemical composition(%)

Physical properties

Process

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

Since the material outside the seam welding is thicker, the amount of deformation during the crimping process is larger and unevener than that of the other parts. Therefore, if the carbon content of the material exceeds the standard, the cracking phenomenon is liable to occur. In production, the materials that are frequently found in large-scale flanging and curling are mostly imported from Russia and the United States, or some steel plates with severe corrosion. 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 steel barrel crimping process.