Steel bending pipe bending is divided into two types: cold simmering and hot simmering. Cold simmering is to bend the steel bending pipe at normal temperature. There is no need to fill the pipe with sand, and there is no need to heat the simmering steel bending pipe section. It is easy to operate and saves manpower and material resources. This method is most suitable for simmering galvanized steel pipes, stainless steel pipes, and non-ferrous metal pipe elbows such as copper and lead pipes.
Cold stewing steel bending pipe must rely on machine tools for processing. Commonly used cold stewing steel bending pipe equipment includes: manual steel bending pipe machines, electric steel bending pipe machines hydraulic steel bending pipe machines, etc. Using a cold bending machine, elbows with a nominal diameter of no more than 250mm can generally be made. When simmering large diameter thick wall pipes, medium-frequency steel bending pipe machines are often used.
When using cold simmering steel bending pipe equipment for steel bending pipe, the bending radius of the elbow should not be less than 4 times the nominal diameter of the steel pipe. When using a medium frequency steel bending pipe machine to perform a steel bending pipe, the bending radius of the elbow only needs to be no less than 1.5 times the nominal diameter of the steel pipe.
Metal pipes have a certain degree of elasticity. During the cold simmering process, when the external force exerted on the steel pipe is removed, the elbow will spring back to an angle. The size of the rebound angle is related to the material of the steel pipe, the thickness of the pipe wall, and the size of the bending radius. For general cold-simmering carbon steel pipes with a bending radius of 4 times the nominal diameter of the steel pipe, the rebound angle is approximately 3° to 5°. Therefore, when controlling the bending angle, consideration should be given to increasing the angle of this rebound.
First, manual steel bending pipe simmering pipe
Manual steel bending pipes are divided into two types: portable and fixed. Steel pipes with a nominal diameter not exceeding 25mm can be simmered. Generally, several pairs of tires corresponding to the outer diameter of commonly used steel pipes are required.
The structure of the portable manual steel bending pipe is shown in Figure 1-12. This steel bending pipe is composed of a handle with a steel bending pipe tire and a movable baffle. During operation, place the simmered steel pipe in the steel bending pipe tire groove, fix one end on the movable baffle, and push the handle to bend the steel pipe to the required angle. This kind of steel bending pipe is characterized by its lightness and flexibility, which can be used for bending operations in any situation. It is most suitable for piping such as electrical appliances and instruments.
The structure of the fixed manual steel bending pipe is shown in Figure 1-13. It is a commonly used manual steel bending pipe tool in current construction. This steel bending pipe device is composed of a fixed tire wheel 3, a movable tire wheel 2, a push frame, and other components. The edges of the tire wheels have inwardly concave semicircular grooves, and the diameter of the semicircular groove is consistent with the outer diameter of the steel pipe to be bent. When simmering the pipe, first select a suitable tire according to the outer diameter and bending radius of the steel pipe to be simmered, fix the fixed tire on the operating platform with a pin, insert the movable tire on the push frame, and place the steel pipe to be bent. In the groove between the fixed tire wheel and the moving tire wheel, one end is fixed in the steel pipe holder, and then the handle is pushed to rotate around the fixed tire wheel until it is bent to the required angle.
Second, an electric steel bending pipe machine simmers pipes
At present, the common electric steel bending pipe machines include WA27-60, WB27-108, and WY27-159. Type WA27-60 can bend steel pipes with an outer diameter of 25-60mm; type WB27-108 can bend steel pipes with an outer diameter of 38-108mm; type WY27-159 can bend steel pipes with an outer diameter of 51-159mm.
The electric steel bending pipe machine uses a motor through a transmission device to drive the main shaft and the steel bending pipe mold fixed on the main shaft to rotate together to simmer the pipe. This is a diagram for the electric steel bending pipe machine to simmer the pipe. When simmering the pipe, first place the steel pipe to be bent along the guide mold between the steel bending pipe mold and the compression mold, adjust the guide mold so that the steel pipe is at the common tangent position of the steel bending pipe mold and the compression mold, and make it Align the bending point with the tangent point, then use a U-shaped pipe clamp to clamp the pipe end on the steel bending pipe mold, then start the motor to start simmering the pipe, so that the steel bending pipe mold and the compression mold bring the steel pipe around the steel bending pipe mold. Rotate and stop when reaching the required bending angle, remove the U-shaped pipe clamp, loosen the compression mold, and take out the steel bending pipe.
When using an electric steel bending pipe machine to simmer the pipe, the steel bending pipe mold, guide mold, and compression mold used must match the outer diameter of the steel pipe to be bent, to prevent the quality of the steel bending pipe from not meeting the requirements after simmering.
When the outer diameter of the steel pipe to be bent is greater than 60mm, a bending mandrel must be placed inside the pipe. The outer diameter of the mandrel is 1-1.5mm smaller than the inner diameter of the steel pipe, and is placed slightly in front of the bending point of the steel pipe; the intersection line between the conical part of the mandrel and the cylindrical part must be placed on the bending surface of the steel pipe. As shown in Figure 1-15. If the mandrel sticks out too far, the mandrel will crack during bending; if the mandrel sticks out too far, the steel bending pipe will be too round. The correct position of the mandrel can be obtained experimentally. When using a mandrel to simmer the pipe, the debris in the lumen of the steel pipe to be simmered should be cleared before simmering the pipe. If possible, a little engine oil can be applied to the inner wall of the steel pipe to reduce the friction between the mandrel and the pipe wall.
Third, hydraulic steel bending pipe machine simmering pipe
The hydraulic steel bending pipe machine mainly consists of two parts: tire jacking and pipe holder. The function of the tire jack is the same as the steel bending pipe mold of the electric steel bending pipe machine. The function and shape of the pipe holder are the same as the compression mold on the electric steel bending pipe machine.
When using this kind of steel bending pipe machine to hydraulically simmer the pipe, first move the top tire behind the pipe holder, then place the steel pipe in the arc groove between the top tire and the pipe holder and make the center of the bent part of the steel pipe and the center of the top tire Align the points, then start the machine to bend the steel pipe to the required angle. After bending, reverse the vehicle and return the top tire to its original position, take out the simmered steel bending pipe, and check the angle. If the angle is not enough, you can continue to bend.
This steel bending pipe machine is simple, lightweight, and powerful, and can bend steel pipes with larger diameters. However, when bending steel pipes with larger diameters, the steel bending pipe section is often severely deformed. Therefore, it is generally only used for bending steel pipes with an outer diameter not exceeding 44.5mm.
When using this steel bending pipe machine to simmer pipes, the angle of each bend should not exceed 90°. During operation, you also need to pay attention to adjusting the distance between the two tube supports to just allow the top tire to pass. If it is too small, it will cause the top tire to press against the pipe supports and damage the steel bending pipe machine; if it is too large, the pipe sections between the pipe supports will be bent and deformed during bending, which will affect the quality of the steel bending pipe.
Fourth, medium frequency steel bending pipe machine
The medium-frequency steel bending pipe machine uses medium-frequency electric energy induction to perform local annular heating of the steel pipe. At the same time, the steel pipe is mechanically driven to rotate and sprayed with water for cooling, so that the steel bending pipework can be continuously coordinated. Using this pipe machine, an F325×10mm elbow can be bent, with a bending radius of 1.5 times the nominal diameter of the steel pipe, which improves work efficiency by nearly 10 times compared to coke-heated steel bending pipes. Compared with common cold-stewing steel bending pipe equipment, this steel bending pipe machine has the advantages of less space, low cost, no need for expensive molds, and easy adjustment of the bending radius.
When steel bending pipe shaping, first remove the floating rust and dirt on the surface of the steel pipe to be bent, install the steel pipe chuck that matches the specifications of the steel pipe to be bent on the rotating arm, and adjust the center line of the chuck to the required bending radius. Then fix it; then, adjust the position of the support roller so that the distance from the center line of the bent steel pipe to the center of the swing arm axis is equal to the bending radius. Adjust the height of the support roller and bracket so that the center line of the steel bending pipe is in the same plane as the center of the chuck and parallel to the plane of the rotating arm; insert the steel pipe into the heating ring and clamp it in the chuck; adjust the heating ring, so that the gap between the inner side and the outer surface of the steel pipe is consistent. Turn on the intermediate frequency unit for heating. When the steel pipe is heated to 950-1000°C (orange), immediately start the motor to steel bend the pipe; at the same time, open the cooling water valve and spray water to cool the local parts. When steel bending pipe shaping, if the temperature of the steel pipe is high, the rotating arm speed can be appropriately accelerated; otherwise, the rotating arm speed can be slowed down so that the heating zone of the steel pipe always maintains the same temperature. When the steel bending pipe is bent to the required angle, stop heating and the motor (but do not stop the steel bending pipe in the middle), and continue to cool the steel bending pipe with water until the steel bending pipe cools to normal temperature. Take out the steel bending pipe and check the bending angle and quality. does it reach the requirement?
Post time: Mar-18-2024