Discussion on the experience of hot rolled plate barrel
Xining Barrel Factory Ni Mingxiang
Due to the difference in mechanical properties between hot rolled sheets and cold rolled sheets, the barreling process is also different.
Since the cold-rolled sheet has good plasticity, toughness and surface roughness, it is easy to ensure the quality of the barrel. Compared with cold-rolled sheets, hot-rolled sheets have defects such as oxide layer, poor toughness, and large thickness error. Therefore, weld cracks are likely to occur when barrels are made from hot-rolled sheets, tearing at the ribs and punching during punching. And so on. If the hot-rolled steel drum is produced according to the cold-rolled sheet processing technology, the waste defective barrel is prone to occur. Although it can meet the requirements of use after repair and repair welding, but the appearance quality is poor, and it takes a lot of repair time and production costs, which increases the labor intensity of workers and increases the cost.
To improve the quality of hot-rolled steel drums. I think we should pay attention to the following points: Take 200L barrel as an example.
1. Correct control of the size of the blank
The diagonal dimension error of the blanking should be controlled below 2mm. If it is too poor, there will be obvious misalignment at the seam opening after the rounding. The short side of the misalignment produces four layers of curling when sealing, causing leakage of the steel drum.
2. After heating, punch the hole
When punching the small hole at the top of the barrel, the hot-rolled steel plate is brittle, and the punching portion is easily broken. For example, the heating method using oxygen, local heating, and side-baking, the cracking phenomenon is basically eliminated.
3. Correction of the edger
Since the hot rolled sheet has an oxide layer and a large thickness error, it is necessary to pay attention to the thickness of the edging. The edger should be adjusted accordingly.
1 Adjustment of the feed port guide. The parallelism of the feed guide rail gap is adjusted to within 5 mm.
The lower rail is adjusted to be flared, but the middle should be controlled within 8mm. see picture 1.
2 selection and adjustment of the grinding wheel. The grinding wheel is easy to use silicon carbide material with a particle size of 36#. When grinding the grinding wheel, the wheel angles on both sides of the grinding wheel should be rounded to make the middle bulge, and the two sides should be ground with the middle. The width of the edging is generally 15 to 20 mm.
4. Barrel roll
Since the thickness of the hot-rolled sheet is uneven, it is necessary to adjust the gap of the press roll according to the winding error at any time, and the round gap is adjusted to be small, and the round gap is adjusted to be large.
5. spot welding
The spot area of â€‹â€‹hot-rolled sheet spot welding should be controlled at 5.5-5.5 mm2. When the thickness is less than 5mm2, the spot weld is easy to burn through. Spot welding is suitable for four points. The two solder joints are preferably 20-30 mm from the edge of the barrel.
6. Seam welding
The wire speed of the welding wheel should be accelerated when welding hot rolled sheets. The diameter of the welding wheel is not less than 135mm. The working surface of the welding wheel is 6.5 to 7 mm wide.
The welding wheel should be assembled in an interference condition and should not be loose. If there is oxide layer or impurity at the weld, it must be cleaned before welding, otherwise the weld will burst or break down.
The width of the flange is 3/8. If the top of the bucket is 25mm wide, the width of the flange is 25 x 3/8 = 9.375mm. As shown in Figure 2. The angle is greater than 90 degrees.
Due to the poor elongation of the hot rolled sheet, the rib is easily broken. In our factory, a batch of 2-3% barrels of hot-rolled sheets appeared to rise in this process. If the rib height is negative tolerance 13-2, this phenomenon has improved.
The sealing process is a key process in barrel making. According to years of experience, the shape of the head sealing wheel is different when producing cold-rolled plate barrels and hot-rolled plate barrels. Take a 200L five-layer crimping bucket (1.2mm) as an example. When the shape of the head sealing wheel of the hot-rolled plate barrel is as shown in Fig. 3, the sealing effect is the best. For example, if the barrel is cooled, the dimensions are slightly smaller than the figure.
For the rest of the process, the hot rolled sheet is the same as the cold rolled sheet.
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