Technical Problems Of Steel drum seam welder transformation

In recent years, especially after the accession to the WTO. The expansion of foreign trade, the introduction of foreign advanced technology and equipment, with the rapid development of China's cooperage industry. Take the steel drum barrels seam welding, for decades, has been using Shanghai welding machine factory production FN-150-5-type seam welder, welding take sides welding, to take the edge width of 12mm. Now, this phenomenon is gradually changing.

The beginning of reform and opening up, the domestic introduction of a few Karan multi cooperage production line and several automatic seam welder. Imports seam welder welding steel drums take the side width of only of 2 ~~ 3mm barrels after welding. Not only the aesthetic appearance of the steel drums, beautiful, but also help to ensure the quality of steel drums seaming, while also saving raw materials. Although this welder has so many benefits, but because the price is very expensive. Most of cooperage companies can only feel powerless and frustrated. By this time, the domestic insightful people optimistic about this opportunity and decided to develop the manufacture of welding electrical control box, without having to spend too much money can take the side seam welding 4mm desire through technological innovation, so that most of the cooperage seam welder . Until recent years, with the fierce competition in the market and the expansion of foreign trade. Our steel drums with their inner packing of goods across the oceans, in order to narrow the gap with foreign counterparts, compels us as soon as possible to improve our steel drum packaging process, the improvement of the steel drums weld process is one of them.

Following transformation seam the welder in steel drums welding process in the emergence of some practical issues are discussed.

Barrels seam welding flange when both ends of the barrels are cracking, and some even nearly 1OOmm long weld leakage.

2, at both ends of the barrels flanging no damage, but bulging tendons ring ribs cracking.

3, welding the flying stab affect the intrinsic quality of the appearance of the quality of the steel drums and full opening of the barrel.

The above three issues, the problems often encountered by many the cooperage enterprises in the actual production, To this end, on the basis of full practice, we were careful study.

A welding process parameters on the quality of the seam welding barrels

Steel drums barrels are welding principle of resistance welding. Welding is pressed together by welding heat, the steel melt after dissolving. The welding heat Q = I2Rt, where: Q - the heat generated; I - welding current; R - resistance between the electrodes; t - energized time.

Welding current, the resistance between the electrodes, the energization time can be seen from the formula, the factors affecting the welding quality of the barrel body, and the resistance of the electrode Q is determined by the size of the electrode pressure; welding current has a direct relationship with the grid voltage; energized Q barrels are welding speed. Therefore, usually, reflected affect the quality of the barrel body welding process parameters (see Table 1) by: the welding current, the electrode pressure, welding speed, welding time and quiescent time.

1, the barrel body of the welding current is seam welded to formed nugget desired heat sources, such as described above, is the resistance heat generated by using a current through the weld zone. Under the conditions given in other conditions, the welding current size determines the nugget penetration rate and the amount of overlap. Welding drums barrel, the nugget average weld penetration rate of plate thickness of 30 to 70%.45 to 50% for the best. Should not be in the 15-20% airtight welding seam nugget amount of overlap.

When the welding current exceeds a certain value, and continue to increase the current the weld penetration rate can only increase the nugget and the overlap amount, but does not improve the strength of the joint, which is not economical. If the current is too large, but also produce the barrel body indentation too deep and weld burn through barrels defects.

2, the electrode pressure

The barrel body seam welding electrode pressure have a significant impact, the total resistance R between the two electrodes with the increase of the electrode pressure, R is significantly reduced. The welding current is slightly increased, but not affect the reduction of welding heat caused by the R decreases. Thus, the weld strength is always decreases with the increase of the electrode pressure. The electrode pressure is increased at the same time, increasing the welding current, or extension of the welding time, can compensate for the impact resistance decreases. So as to maintain the same weld strength. Such welding conditions are conducive to improve the welding strength stability. Electrode pressure is too small, it will cause splashing, but also make the welding strength is lowered. In the same time, the electrode pressure is too high, the barrels will be too deep indentation, deformation and loss of accelerated welding (welding wheel) roulette. Insufficient pressure is easy to produce shrinkage, and due to the contact resistance is too large easy to make welding roll disc burning and shorten its life.

3, welding time and rest time

Barrels seam welding, is mainly controlled by the weld time the size of the nugget, and cooling time control of the amount of overlap. In the lower welding speed, welding and the ratio of the quiescent time of 1.25:1 to 2:1, and satisfactory results can be obtained.When the welding speed is increased, the spot pitch increases, this time to obtain the same amount of overlap of the weld, this ratio must be increased, this end, in a higher welding speed, the welding and the quiescent time ratio should be 3:1 or higher.

4, welding speed

The barrels are welding speed barrels materials, thickness, material direct, special panels of different manufacturers of steel drums, welding parameters when welding is different, we do not enumerate. In short, the welding speed nip barrel body seam welder roller disc (welding wheel) and the tub body of the contact area, and the welding wheel and the heated parts (weld edges ride) contact time, when the welding speed is increased , in order to obtain sufficient heat must be increased to the welding current.Excessive welding speed will cause burning of the surface of the barrel body and the electrode adhesion, so even if the current barrel body seam welder enough external cooling water, the welding speed can not be too large, but should be limited.

Second, the mechanical parts of the welder and procedure before the barrels barrels welding quality

Produce in front of three phenomena addition to the welding parameters, the adjustment of the welding machine itself has a great relationship. Because under normal circumstances, in the welding of the barrels, the electrode pressure and the welding speed is infrequently changing parameters This parameter is changed, unless the thickness of the material of the welding barrels undergone great changes. When the thickness of the material of the welding barrel body of 1.2 or 1.0 when the electrode pressure and welding speed without changing, and it will not affect the quality of the welding of the barrel body. But if the barrels are prop rack is too high or too low, directly change the size of the the barrels welding electrode pressure If the prop barrels rack is too high, the electrode pressure increases, the barrels are welded out obvious indentation. Front, we talked with the electrode pressure increases, R significantly reduced. Welding the welding heat generated at this time will be reduced due to the electrode resistance R decreases the welding strength will also be reduced with the increase of the electrode pressure. Therefore leakage or the the flanging rupture; If the prop barrels rack is too low, the the electrode pressure decreases, welding out of the barrel itself will generate significant Peach plow, that the outside of the barrel body weld is too high, is not an arc. The electrode pressure decreases at this time, R is significantly increased. Welding the welding heat generated at this time will be increased due to the increase of the electrode resistance R will produce the burnthrough or splashing phenomenon, will be prone to leakage or burring cracking phenomenon.

Check full barrels are high and low the seam welder prop rack should adjust its level prop barrel charm Level adjustment parallel to the horizontal is better. If two spiky, due to the different size of electrode pressure caused by different size of the end of the barrel body weld head and weld strength, and therefore leakage or rupture.

Second, check the seam welder nose is normal, sometimes swing under the nose or on the head of the long-term poor lubrication caused by lubricating oil dry on the head can not move down the technological requirements of the position. These are the main factors that affect the barrels are welded, we have encountered in the production of

Third, check whether the correct air pressure the trachea, valve leakage phenomenon.

Fourth, check the barrels are spot welded two take the side of the correct size, the process requirements barrels take the side of 4mm, so both ends can not appear too large error, or can also cause welding, one end of the barrel body leak.

Third, the easiest way to solve the problem

Earlier analyzed theoretically produce steel drum barrels are welded leakage, but under normal circumstances, in addition to the equipment reasons, most of the more human factors. Therefore, resolved, first check the barrels take the edge width, suitable barrels take the side width, most concise way to the minimum welding speed, welding, welding a barrel body, according to the the welding current situation appropriate increase welding current until the current does not produce flying assassination date, then welded the barrel itself will not seep full. At this point, if you would like to increase the welding speed, corresponding welding current is increased, the two are complementary. However, due to the speed of many operations in order to accelerate the work. Blindly increase the welding speed, the control box the welding specification disorders, and therefore caused the barrels are leaking or cracking after welding.

The table is in a cooperage enterprise production a set of process parameters, for reference only. Because the accuracy of the welder itself, transformation methods, the accuracy of the controller and a welding work environment, the raw materials used, the operator proficiency and other factors will have an impact on the barrel body welding parameters.

Based on the practical experience of the past, the production process, under normal circumstances, welding speed, electrode pressure is infrequently changed, in the smaller range of material changes, they are a constant. But the welding current can be a frequently changing parameter, it must not only varies with the thickness of the welding material, the material changes, but also with the change in voltage of the grid and are subject to change.