WPL6 tee

The common problems of WPL6 tee pre welding, such as the fault edge, directly lead to the degradation or waste of large diameter carbon steel tee. Therefore, pre welding requires strict control of misalignment. When the whole or most of WPL6 tees are at the edge of fault, the difference is generally due to

(1) inadequate seam opening adjustment

(2) Joining roll (the adjustment of the roll is not on the right side of the circumference angle, or with the pipe centerline as the axis, the elongation of the radial roll is about asymmetric, or the relative pressure roll is inconsistent, and there is no pressure circle); The pre bending was not in place, which caused the straight edge phenomenon. When the head or tail of the tee shows a fault side error, it is usually because the position of the inlet and outlet roller table is incorrect; The center of the ring is wrong

(3) Joint pressure rolling ring is not good, and individual roller position error

(4) The molding is not good (the height difference of tee on both sides after molding)

(5) The opening width exceeds 150 mm

(6) Hydraulic system pressure fluctuation

2, burn through

If it is clear and time-consuming after welding, the normal production process will be affected; Unclear, the tee is welded to shape and the internal weld is butt welded. Burn through will affect the welding quality of the surface and interior, and filling is required. The reasons for stacking and burning on the back are generally:

(1) The joint is not tight, and there may be a low-pressure hydraulic system

(2) Poor molding and large roundness error

(3) Improper selection of pre welding process parameters. The welding current and arc voltage shall have appropriate welding speed. The welding speed and line energy are too high or too low, which is easy to burn and flash back

3, stoma

preweld porosity leads to internal defects of internal and external welding. The porosity in the pre weld is generally caused by the poor quality of the maintenance gas, such as insufficient water, pressure and flow

(2) Part of the welding gun is blocked, the gas hood composed of maintenance gas is uneven, and there is no concrete clinical effect based mixing

(3) There is rust and oil pollution on the groove

4, the weld composition is poor

The shape of WPL6 tee weld is poor, which affects the surface and inside welding marking, affects the stability of welding process, and thus affects the welding quality. Welding composition is closely related to wire energy. The welding current and arc voltage are stable, the welding speed increases, the weld penetration and the weld width decrease, resulting in poor welding composition. When porosity occurs in the weld, the weld composition is generally poor