In the spiral welded pipe technology, the forming angle is an important parameter, which refers to the spiral axis formed by the center line and the width of the strip (pipe) and the angle (acute angle) of the coil after the spiral welded pipe production (pipe) is welded. Diameter, stress and productivity have a certain relationship.


RELATIONSHIP BETWEEN SPIRAL WELDED PIPE WIDTH AND DIAMETER OF FORMING ANGLE (PIPE) OF STRIP STEEL
In some cases, the width of strip and the change of forming angle directly affect the change of pipe diameter, while the diameter of steel pipe with different width of the same band can be used, and different forming angle can be used. Considering the feasibility and economy of production, the width and diameter ratio of strip steel is a certain limit and scope. From the economic point of view, the smaller the forming angle, the higher the productivity. If the forming angle of 30 degrees is equal to that of 50 degrees, the same output will be about one fourth of the diameter of the pipeline. In terms of feasibility, the small steel with smaller roundness after forming has poor steel quality.


Relational Forming Angle and Welding Stress
Spiral weld is exposed to less stress than straight line, only 75% - 90% of straight line, so it can withstand more pressure. Longitudinal wall thickness can be reduced by 10%-25% compared with the same diameter. Therefore, the wall thickness of the radial stress is the decisive factor. The angle between the longitudinal direction of the straight line tangent to the cylindrical surface of the tube formed by the helical joint angle is formed.