What Are The 4 Different Kinds of Pipe Bending?
June 03, 2023
There are many processing methods for bending pipes. The bending forming method can be divided into Roll Bending, Press Bending, Rotary Draw Bending, and Mandrel Bending.
According to the bending process, whether there is a mandrel, it can be divided into core bending and coreless bending. and according to whether the bending is heated, it can be divided into cold bending and Hot bending. Each different bending method has a unique process and conditions and also has the effect of solving a certain bending quality problem.
Roll Bending is usually used for thick-walled tube bending, as shown in the figure below.
Place the tube blank between three or four or more rollers, each roller has a groove with an inner diameter slightly larger than the outer diameter of the tube and a section circumference slightly smaller than the semicircle of the tube blank, each roller rotates and moves in different directions, The tube blank is rolled to form a certain curved shape.
Multi-roller bending can improve the bending accuracy of the pipe, reduce the distortion of the bending cross-section, and improve the degree of uniform bending of the pipe. Sometimes it can be used for thin-walled pipe bending.
Mandrel Bending is a bending process that strongly controls the cross-sectional shape of the bent pipe. It differs from ordinary coreless bending in that the mandrel is pre-installed in the tube blank during bending.
Press Bending is similar to draw bending, and is the bending of pipes achieved by the combined action of additional or derived axial push force and bending moment.
The additional axial force can reduce or counteract the effect of the tangential pulling force on the convex side of the bend so that the wall thickness of the bend can be suppressed from thinning or cracking, but at the same time, the tangential compressive stress on the concave side of the bend can be increased, and the wall can be increased to wrinkled.
Press bending is high production efficiency, and easy to adjust bending die. It can be used to bend medium and small-diameter elbow fittings with straight pipe sections.
Rotary Draw Bending is on the basis of pure moment bending, an axial force is added to realize pipe bending.
When the pipe is drawn and bent, the pipe blank passes through three horizontal support rollers and is fixed on the radius arm integrated with the clamp. When the rotating arm rotates, it drives the pipe blank to produce bending deformation.
During draw bending, the radius of curvature of the bend can be changed by adjusting the distance between the support roller and clamp and the axis of the runner.
According on whether the bending is heated, pipe bending can be divided into cold bending and Hot bending. Let’s talk about Hot Bending.
Hot bending is a traditional plastic processing method, which uses heating to soften the tube blank and enhance its plastic deformation ability. When the shape of the tube product is not suitable for cold bending, hot bending can be considered.
The heating source can be gas, coal, resistance furnace, and Induction Heating. Nowadays, Induction heating is widely used in the pipe and tube industry due to the following advantages.
ㆍPipe heated uniformly by Induction Heating Machine brings Good Quality bent pipe: very less Distortion, very less Wall Reduction, and good Ovality.
ㆍPipe heated fast by Induction Heating brings High Efficiency, Low operating cost, and Low Energy Consumption.
ㆍWith induction Heating pipes and beams in different materials such as Carbon & Alloy steel, Stainless steel can be bent.
ㆍPrecise temperature control to maintain a constant heating temperature during bending.
ㆍBending of Square tube, Rectangular tube, Angle steel, and I-beam
ㆍWith induction heating, Seamless pipe & Welded pipe can be bent.
ㆍEasy to operate with friendly HMI of Siemens PLC and Touch Panel
ㆍEnvironmental protection and energy saving
Some cases of Hot Pipe Bending with Induction Heating.
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