Spiral welded pipe production uses hot rolled coil. The alloy content of the coil is often lower than similar grades of steel plate, improving the weldability of the spiral welded pipe. Due to the rolling direction of spiral welded pipe coil is not perpendicular to the pipe axis direction, the crack resistance of the spiral welded pipe materials.
Because of the unique performance of the spiral pipe, when spiral welded pipe blasting occurred, the weld suffered stress and co-stress is relatively small, blasting the mouth is generally not the origin of the spiral weld, so the higher security. Spiral weld near the defect with parallel spiral weld force is smaller, so the risk of expansion is not.
Steel pipe subjected to internal pressure, usually in the wall on the two main application of force, the radial stress δY and axial stress δX. Weld resultant stress δ = δY (l/4sin2α + cos2α) 1/2, which, α is the helix angle of the spiral weld pipe. The helix angle of the spiral weld pipe is generally 50-75 degrees, so the spiral weld large resultant stress. In the same work under the pressure of the same diameter spiral welded pipe wall thickness can be reduced a lot, spiral pipe plant can be made into a small caliber.
Post time: Dec-02-2019