The high-frequency welded pipe(ERW pipe) is a welded tube with a high welding speed and a small welding heat-affected zone. Welding can not be cleaned for steel pipes, thin-walled pipes can be welded, and metal pipes can be welded.
Advantages and disadvantages of high-frequency welded pipe edge forming
Edge forming is the first step in the high frequency welded pipe forming process, the purpose of which is to bend the edge portion of the strip to the curvature of the extrusion roll radius. The edge forming of the traditional process adopts single-radius forming, while the modern process adopts double-radius forming.
The initial double-radius molding is just a simple double-radius upward bending. Later, it developed into W forming. The bending of the middle part of this forming method adopts a reverse protrusion, which makes the edge bend more fully, and the linear speed difference of each part of the pass is smaller during forming.
The edge forming generally adopts the solid bending method. In cold roll forming, solid bending generally refers to double-sided bending of the strip, and empty bending refers to single-sided bending. In edge forming, there are three basic types of solid bending passes: single radius, multi-curve and involute.
1.Single radius solid bending forming
The single-radius solid-bending pass and the strip are closed in line contact, and the strip is pushed into the pass by external force and then bent and formed. The pass type of this roll is a single radius of curvature, which can only be bent to a specific specification of the radius of curvature, and the rolls have no commonality
The advantages of single-radius solid bending forming:
(1) the strip is well centered and guided, and it is not easy to deviate from the rolling center;
(2) the curved strip is subjected to a large forming force of the upper and lower rolls, the bending is sufficient, and the forming area has a small rebound;
(3)The roll pass curve is simple and easy to process .
Disadvantages:
(1)The commonality of the rolls is poor;
(2) the line speed difference of each part of the pass is large, which may easily cause scratches on the pass and the surface of the strip;
(3)it is difficult for the strip to enter the cavity.
2. Multi-curve real bending forming
The pass and strip formed by multi-curve solid bending are line-contact closed type, but the pass of the upper and lower rolls has changed into multiple curves with different curvature radii. There is a certain commonality. The upper part of the multi-curve forming frame should adopt a rotatable structure, and the required forming curvature can be selected by adjusting the angle; the lower roll is generally a flat roll, and the center distance of the roll sheet can be adjusted to correspond to the pass curve of the upper roll.
Advantage:
(1) The rolls have a certain range of commonality;
(2) It is more convenient to adjust;
(3) The contact surface between the hole pattern and the strip is small, and the surface is not easily scratched.
Shortcoming:
(1) The pass curve is more complex and difficult to process;
(2) The frame structure is relatively complex;
(3) The strip center is easy to deviate from the rolling center, and the forming elastic recovery is relatively large.
Advantages and disadvantages of high-frequency welded pipe edge forming
Edge forming is the first step in the high frequency welded pipe forming process, the purpose of which is to bend the edge portion of the strip to the curvature of the extrusion roll radius. The edge forming of the traditional process adopts single-radius forming, while the modern process adopts double-radius forming.
The initial double-radius molding is just a simple double-radius upward bending. Later, it developed into W forming. The bending of the middle part of this forming method adopts a reverse protrusion, which makes the edge bend more fully, and the linear speed difference of each part of the pass is smaller during forming.
The edge forming generally adopts the solid bending method. In cold roll forming, solid bending generally refers to double-sided bending of the strip, and empty bending refers to single-sided bending. In edge forming, there are three basic types of solid bending passes: single radius, multi-curve and involute.
1.Single radius solid bending forming
The single-radius solid-bending pass and the strip are closed in line contact, and the strip is pushed into the pass by external force and then bent and formed. The pass type of this roll is a single radius of curvature, which can only be bent to a specific specification of the radius of curvature, and the rolls have no commonality
The advantages of single-radius solid bending forming:
(1) the strip is well centered and guided, and it is not easy to deviate from the rolling center;
(2) the curved strip is subjected to a large forming force of the upper and lower rolls, the bending is sufficient, and the forming area has a small rebound;
(3)The roll pass curve is simple and easy to process .
Disadvantages:
(1)The commonality of the rolls is poor;
(2) the line speed difference of each part of the pass is large, which may easily cause scratches on the pass and the surface of the strip;
(3)it is difficult for the strip to enter the cavity.
2. Multi-curve real bending forming
The pass and strip formed by multi-curve solid bending are line-contact closed type, but the pass of the upper and lower rolls has changed into multiple curves with different curvature radii. There is a certain commonality. The upper part of the multi-curve forming frame should adopt a rotatable structure, and the required forming curvature can be selected by adjusting the angle; the lower roll is generally a flat roll, and the center distance of the roll sheet can be adjusted to correspond to the pass curve of the upper roll.
Advantage:
(1) The rolls have a certain range of commonality;
(2) It is more convenient to adjust;
(3) The contact surface between the hole pattern and the strip is small, and the surface is not easily scratched.
Shortcoming:
(1) The pass curve is more complex and difficult to process;
(2) The frame structure is relatively complex;
(3) The strip center is easy to deviate from the rolling center, and the forming elastic recovery is relatively large.
