Tube bending methods
Pressure vessels in the pipe bending molding
There are a variety of methods of pipe bending, generally manual bending and mechanical bending. Mechanical bending methods and a variety of methods, such as pressure bending method, roll bending method, back bending method and squeeze bending method. Regardless of which bending method, the main contradiction in the entire bending process is how to overcome the problem of local deformation. The most widely used in the project is the manual bending and bending back to the pipe bending process. Back bending method is in the rotary pipe bender bending, it can be divided into two types of mold bending and mold bending.
Manual bending
Manual bending does not require special equipment and complex process equipment, it can bend a variety of radii, angles and space towards the bend. But this bending mode of labor intensity, low productivity, quality is not stable enough.
Manual bending of steel pipe using hot bending, for stainless steel and non-ferrous metals should be used for cold bending. Before bending in the tube first filled with filler, steel pipe filler is generally pure, dry fine sand, stainless steel and non-ferrous metal filler is appropriate to use rosin, lead and other low melting point substances, in order to prevent wrinkles and reduce the degree of ellipticity.
Molded pipe bending
This category of pipe bender are using mold bending. The main mold has a disc-shaped grooved wheel and ram's horn core head of two kinds. Disc-shaped groove wheel bending pipe bending mold on the outside of the pipe, half of the bent pipe lying in the groove, the other half of the pipe bending area with a groove of small rollers (also known as compression rollers) pressed. The end of the tube is fixed by the chuck on the disc-shaped bending mold, if the compression roller does not move, disc-shaped bending mold active rotation to complete the bend, known as pull-bending; if the tube is subjected to thrust so that the disc-shaped bending mold to complete the bending of the follower, known as push-bending; if the disc-shaped bending mold does not move, the compression roller pressed the tube to complete the bending of the bending around the disc-shaped bending mold to complete the bending of the bending, known as the pressure bending type.
Sheep's horn mandrel bending tube when the bending mold in the tube on the inside, sheep's horn mandrel like sheep's horns, the axis of the length of 1/4 circumference, the bending radius and the same bending tube, the maximum bending angle of 180 °. Sheep's horn core head thin end than the inner diameter of the billet is slightly thin, the billet from the thin end of the set into the thick end is the exit, slightly thicker than the inner diameter of the billet. When bending the billet is first heated and then set into the mold, the tube under the action of thrust bending and expansion of the two processes, sliding out of the end of the core head when the bending process.
Mold bending
This bending method of pipe bending machine used without a special decision to bend a certain bending radius of the bending mold. It can be divided into two types of bending and push bending. Bender has a rotating arm, the arm length can be retracted, when the pipe is fixed in the rotating arm, the central axis of the pipe to the rotating center of the arm is the distance between the bending radius. At work, the tube is covered with a copper induction loop, induction loop through the medium frequency (for thicker tubes) or high frequency (for thin tubes) electricity will be partially heated to 900 ~ 950 ℃, and then bend the tube. If the rotary arm active rotation of the tube back to the bend forming known as pull-bending; if the tube end by the thrust, the tube to push the rotary arm to rotate, thereby realizing the tube back to the bend forming known as push-bending. Immediately after the inductor ring from the inside of a circle of small holes to the bent pipe section of the water spray, so that it quickly cooled. The purpose of the water spray is to make the heating section and the deformation zone is limited to a very small range, thus preventing the tube wrinkles and flattening.
