In recent years, with the continuous improvement of steel drum manufacturing technology, the structure of steel drums has also been continuously updated, and the plates used in the steel drums have also been continuously developed toward thinness. Due to the price increase of steel products, the situation faced by the steel drum production enterprises is very severe. In the face of fierce market competition, the sales price of steel drums is difficult to increase, so barrel makers can only accept high-cost raw materials. In the face of such high raw material prices, it is very difficult for steel barrel manufacturers to make profits. To this end, the steel drum manufacturers do their best and try every means to reduce the production costs and costs of steel drums, so as to preserve their strength and remain invincible in the competition. To this end, the supply and demand sides have basically reached a consensus so that steel drums can be as lightweight and thin as possible while satisfying demand. In this way, the types of steel drums produced by steel drum production enterprises will not be the same as those specified by the national standard, and there will be many steel drum products outside the standard. For example, a 200-liter small-opening asphalt barrel with a barrel thickness of 0.5 mm and a barrel bottom (top) thickness of 0.65 mm; a 200-liter small-opening chemical barrel with a barrel thickness of 0.6 mm and a barrel bottom (top) thickness of 0.8 mm; A 200-liter small opening lubricating oil barrel with a body thickness of 0.8 mm and a barrel bottom (top) thickness of 1.0 mm. At present, thin barrels such as this one are in an endless stream, but due to the fact that most of the processes use the original 200-liter small-opening steel drums and molds, some unexpected problems have arisen in the production process.
The day before yesterday, a friend called to inquire, saying that they had a smooth production of 200 liters of small open drums, but recently produced a batch of 200 liters of small open drums with a barrel thickness of 0.6 mm and a bottom (top) thickness of 0.8 mm. , how to adjust the equipment and tooling also failed to achieve the desired result, not the edge of the tongue appears at the curling, or leakage, and even the phenomenon of tensile edges. As far as I know, such problems have encountered many steel drum companies when they tried to produce thin barrels. They even delayed a lot of time, missed many chances of signing orders, and directly affected the economic efficiency of enterprises and the quality of products. If the technical dimensions of thin steel drums can be scientifically formulated, formulated, and serialized, detours can be avoided in the production process, and work efficiency and product quality can be improved.
Below we first discuss about the barrel flange and bottom, top width of the process to determine the size.
First, the barrel body flange and the bottom (top) edge width and the width of the steel barrel curl, the relationship between the thickness of the steel plate
To determine the correct width of the bottom (top) of the bucket and the width of the flange of the bucket, we must first understand the condition of the curling of the steel drum. Generally, there are three kinds of crimping of the steel drum, ie, double flat curling and double rounding. Curling and triple round crimping; In the past decade, 200-ton steel drums produced by steel drum manufacturers in China have basically adopted triple-round crimping. However, in the past year or two, foreign companies have introduced some production lines to make 200-liter cones. The curling forms are double-edged, so some companies have followed suit. However, considering the strength of steel drums, due to the thinning of their own materials, the corresponding strength of the steel drums is also correspondingly reduced. In order to make the steel drums have a good curling strength, a good roll, and a good sealing performance, it is necessary to seriously carry out the curling. analysis. Therefore, where conditions permit, triple rounding should be used as much as possible.
According to our many years of work experience and the actual situation in the industry at home and abroad, the shape of the triple round curled edge is not a strictly round shape. It has a variety of forms, such as triangular, trapezoidal, elliptical, etc., but its layer. The number is mostly in seven layers, but there are arc transition angles at the corners of the rectangle, and the arc transition angles vary in size. In order to simplify the research process, we set two ideal states. Figure 1 and Figure 2 show two ideal states. The bucket bottom (top) edge width L1 and the barrel flange width L2 we are requesting are between the L1 and L2 values ​​in these two ideal limit states.
Next, the triple hemming condition is studied in the case where the hemming width H and the bottom (top) material thickness are T1 and the thickness of the barrel body material is T2. (Note: In the following studies, S represents the thickness of the hemming; H represents the width of the hemming; Figure 1 shows the ideal state of the rectangular hemming; Figure 2 shows the ideal state of the circular hemming)
In Figure 1, we can easily write the formulas for L1 and L2 (which should be calculated based on the position of the material-neutral layer):
L1=(3T1+3T2)+(H-T1)+(2T1+2T2)+(H-2T1-T2)+(T1+T2)+(H-2T2- T1)
The above formula can be simplified as L1=3H+ T1+3T2 ........................1
L2=(2T2+2T1)+(H-2T1-T2)+(T1+T2)+(H-3T1-T2)
The above formula can be simplified as L2=2H+ T2-2T1 ........................2
Since the width of the barrel and the bottom (top) of the barrel are measured from the surface of the material, Equations 1, 2
The material thickness of the barrel body and bottom (top), which should be added, ie, the upper two types, can be modified to:
L1=3H+ T1+3T2+ T1=3H+2T1+3T2..........................3
L2=2H+ T2-2T1+ T2=2H+T2-2T1 ........................4
In Figure 2, the formula for L1 and L2 can also be calculated by using the formula of the circumference of the circle (it should be calculated by the position of the material-neutral layer):
That is: (formula omitted)........................5
That is: (formula omitted)........................6
Also, because the width of the barrel and the bottom (top) of the barrel are measured from the surface of the material rather than from the neutral layer. Therefore, the thicknesses of the barrel body and the bottom (top) of the barrel, which are to be added to formulas 5 and 6, ie formulas 5 and 6, can be corrected to:
(The formula is abbreviated)........................7
(The formula is abbreviated)........................8
The above calculations are made for the two ideal states, and the actual situation happens to be between the two states. Therefore:
(The formula is abbreviated)............┉.........9
(The formula is abbreviated)............┉...10
The above two formulas can be simplified as:
According to my many years of work experience, under normal circumstances, in the above formula H=2.5T1+3.8T2+K
K = 2.8 ~ 3.0 When the steel plate is thick (T ≥ 1), K takes a smaller value, that is K = 2.8; When the steel plate is thick (T <1), K takes a larger Value, ie K=3
Formula 9 and Formula 10 give the range of the width of the bottom of the barrel (top) and the barrel flange in the case of triple rounding, taking into account the need to fill the sealant when crimping, and the specific conditions of crimping* into the round crimping Therefore, when you take the barrel flanging value, you can take a slightly larger value in the range; when you take the bottom (top) side width, you can take a slightly smaller value in the range.
Second, verify the barrel flange width and bottom (top) side of the correct width
Below we verify the reproducibility of the formula by several examples.
1, when the barrel bottom (top) material thickness T1 = 1.2; barrel body material thickness T2 = 1.0 H = 2.5T1 + 3.8T2+K
=2.5*1.2+3.8*1.0+2.8
=9.6
Substituting H=9.6 into Equation 9 and Equation 10
To: (formula omitted)
2, when the bottom of the barrel (top) material thickness T1 = 1.0; barrel body material thickness T2 = 1.0 H = 2.5T1 + 3.8T2+K
=2.5*1.0+3.8*1.0+2.8
=9.1
Substituting H=9.1 into Equation 9 and Equation 10
To: (formula omitted)
3, when the bottom of the barrel (top) material thickness T1 = 1.0; barrel body material thickness T2 = 0.8 H = 2.5T1 +3.8T2+K
=2.5*1.0+3.8*0.8+3.0
=8.54
Substituting H=8.54 into Equation 9 and Equation 10
To: (formula omitted)
4, when the bottom of the barrel (top) material thickness T1 = 0.8; barrel body material thickness T2 = 0.6 H = 2.5T1 + 3.8T2+K
=2.5*0.8+3.8*0.6+3.0
=7.28
Substituting H=7.28 into Equation 9 and Equation 10
To: (formula omitted)
5, when the bottom (top) material thickness T1 = 0.65; barrel thickness T2 = 0.5 when the material is H = 2.5T1 + 3.8T2+K
=2.5*0.65+3.8*0.5+3.0
=6.525
Substituting H=6.525 into Equation 9 and Equation 10
To: (formula omitted)
From the above verification results, we can see that with the different thickness of steel drums, the production process in the production process will also change, not a mold size and barrel flange size can be all-inclusive, for all steel Barrels are suitable, so in the production of thin steel drums, the process parameters in the processing should be properly adjusted according to the changes in material thickness.
Third, the application of this formula to the production of thin steel drum significance
Above, we have deduced and verified the determination of the size of the flanging and the width of the bottom (bottom) of the triple round rolled steel barrel, which is in line with the actual production. If everyone pays attention, it can be seen that the width of the bucket and the width of the bottom (bottom) of the bottom of the barrel derived from the above are actually already used when we produce the middle bucket, but they are not summarized in the formula and are not used in the 200 liters of steel on the barrel. In the past, we always had an illusion in the production process that the larger the diameter of the steel drum, the greater the width of the cuffs and the width of the lid. Actually, there is no theoretical basis for this. Because of this illusion, many steel drum manufacturers have encountered many unexpected problems in the production of thin steel drums, thereby affecting product quality and delaying production.
From the above formula, we can see that the thinner the material is, the smaller the width of the barrel body and the bottom (bottom) of the barrel, so in the future production, avoid using the same process size and tooling, mold production of different thickness of steel drums, so that Guarantee the quality of steel drums.
[Note: This article has omitted illustrations, formulas, and code names in the text due to problems with web page display. ]