Steel Barrel Production Training - Technical Art 2

First, the basic principles of machining steel drums
Steel drum manufacturing technology is actually a specific application of integrated technology, the production process may seem simple, but it involves many technical fields. For example: steel uncoiling leveling - Rolling shaping techniques; barrel body rolling, flanging, bulging - cold plastic deformation of metallic materials technology; spot weld - metal welding technology; bucket bottom, closure of Production - cold stamping technology; barrel body degreasing rust - chemical surface treatment technology; spray drying - surface coating technology and heating technology; steel drum surface pattern making - printing technology. Which also uses techniques such as rolling, forging technology, hydraulic technology, pneumatic transmission technology, bulging technology, automatic control technology and so on. So, cooperage technology is not a separate discipline, it is a multi-disciplinary integrated application.
Basic processing methods Category:
1, the molding. Using the principle of the steel slab of plastic deformation plate into the desired shape and size of the parts installed, the method is called molding. Slab bending (rolling), bulging, flanging and stretching.
2, the engagement. The use of plastic deformation theory, the separated materials used stitching, seams, curling, buckle seam welding methods such as engaging as a whole, is engaged. In steel drums curling assembly, lamination and other production closure in precisely this way.
3, separation. The use of plastic deformation reached the final stage will produce fracture properties of the material is separated into two or more parts and made part of the processing method. Such as shearing, blanking, punching and other processing.
4, the correction. Used to improve the shape of parts, dimensional accuracy or surface state, such as finishing, trimming, school equality processing.

Second, drums material leveling process principle
Using multi-roll working principle, the plate material in the upper and lower leveling rolls repeated deformation, stress relief, to achieve the purpose of the leveling. The upper and the lower work roll outer, located rigid support roller (wheel) constituting quartet structure type set of rollers. Sheet through leveling, can significantly improve its flat state, improve the quality of the workpiece. Can work independently for a single plate leveling; leveling can also be configured before unwinding, cited material, cut back configuration, stack materials, etc., through the performance of the control system connected into a complete production line for metal coil for leveling , slitting.

Three, steel shearing process principle
The basic principle of the shear process is the use of the upper and lower plates cut scissors, shears the stationary scissors, the scissors cut down, starting scissors pressed into the plate edge, generates a pair of corresponding P and shear moment, so that was cut steel drums rotate. Then, in the other plane shear pair of force is also generated and the corresponding torque T, the two force equilibrium, the steel sheet is cut is no longer rotated until the shear plate under the action of the shearing force is cut .

Fourth, the barrel body rolling process principles
Rolling barrel body works, as shown in (a) shows a symmetric three-roll rolling cross sectional view of the roller. The two symmetrical positions of the intermediate rolls on the roller 1, the roller can be adjusted up and down the driven roller, the roller 2 is a drive roller. The work sheet placed between the upper and lower rollers, the upper roller under pressure, the plate material is bent between the support points, when the two lower rollers rotated, due to the frictional force moves the plate material, so that the entire sheet metal bending occurs uniformly .
According to the bending principle known, only when the sheet feed roller come into contact with the upper part, will achieve the desired bending radius, thus both edges of sheet metal have a length no contact with the roller does not bend, called the Residual straight edge, the remaining straight edge length of approximately half the distance the two lower rollers. Figure (b) and (c) is asymmetric three roll and four roll coil, which aims to reduce both ends of the straight edge.

Fifth, the barrel body welding process principles
As shown below, the barrel body welding schematic. The barrel will be ready to weld pieces placed between two electrodes pressurized, and the welding current is switched to the use of the heat generated by electrical resistance barrel heated and melted to form a situation (or reach a plastic state) after power failure, the pressure continues under the action of forming a strong joint, which is called resistance welding process.

Theoretically, the resistance welding is carried out using internal heat welding, according to the Joule's law, the total heat:
Q = I2Rt
The formula, Q is the internal heat welded steel (Joules); I is the weld zone by drums instantaneous current value (ampere); R is the total resistance between the two electrodes (Ohms); t is the current time by soldering.
From the above equation, the current I larger, the greater the resistance R, the longer power-on time, the greater the heat generated. In these three parameters, the current I of the size of the heat plays the most important role. Therefore, resistance welding, often in order to improve the heat, the most important is to improve the current intensity. Therefore, for the determination of the material, the resistance is constant, and to increase productivity, but also power-on time as short as possible, so that only a high current, low voltage, high efficiency in order to achieve the purpose of resistance welding.
The following figure shows the schematic seam welding, seam welding is actually continuous welding. By the current control means generates a pulse current, which is the frequency, and a combined to form a solder joint. Domestic traditional seam welding is generally frequency, automatic welding generally use high frequency dynamic, so it would be more intensive spot, seam strength and sealing performance will be higher.

Six, barrel body flanging process principles
Barrel body flanging process is based on the principles of sheet material with plastic - referring to steel by external force, the destruction of the integrity of the non-permanent deformation under the conditions of the performance. Barrel body shape deformation process is a gradual forming process. The beginning of the forming, flanging die barrels are applied torque plate bend little deformation of the material within the region, caused by the outer surface of the material yield stress value is less than the limit, caused only elastic deformation within the material; as the mold is applied to increasing pressure values​​, i.e., the bend growing torque, when it exceeds the yield limit of the material, the material of the inner and outer surface of the elastic deformation occurs first state to the plastic deformation, and plastic deformation, the outer surface of the center and gradually extended until it formed.
Flanging barrel body is elongated like a form of flange surfaces, rough deformation zone in the flange when the force as shown below:

Since the deformation zone flange tangential tensile stress in the metal under the action of the tangential elongation, so the limit is mainly determined by flanging coefficients in metal plastic blank. Deformation of the blank flange area of each point in the radial direction of the tangential elongation values ​​are different, the maximum elongation occurs at the outer edge of the barrel body blank, so the flange portion should be to ensure the edge of the metal blank extending long deformable material plastic deformation capacity is less than the allowable limit.
Seven, corrugated ring bars roll forming principle
Roll forming is the use of friction falls under the action of the bellows barrel body under the action of the pressure roller synchronous rotation, and the barrel body in the upper and lower corrugated roller to the roller under the effect of the contact areas to generate a local plastic deformation. The ripples in the bucket is a local body roll forming, material deformation zone by way stretch effect. As shown below.

Barrel body roll forming schematics
Eight, barrel body bulging process principles
Bulging technology is widely used, it can not only bulging ripple, ring bars, swelling cone, you can also flanging, forming a variety of barrel body can form, as shown below, the common types of expansion barrel body type.

Bulging is the use of a shaped tube mold, to a certain tension to the surrounding open, after opening the radial partial radial size larger than the barrel body, so that the barrel body material plastic deformation and queen. Blank bulging plastic deformation when confined to a fixed deformation zone within the sheet does not shift to the deformation zone outside, nor from the outside into the deformation zone. As shown above, the barrel body deformation is limited to changes in the radial dimension, does not participate in the axial deformation. Bulging deformation of the metal in both the local stress state of tension, deformation changes the shape of the district board material is mainly achieved by increasing the surface area of ​​a local, so when the blank thickness bulging thinning is inevitable.