2022-05-15
The pipe mould shall be soaked or sprayed to reduce the temperature after puu-out operations, and the inner wall temperature shall be lowered to ≤50℃ before taking out.
The pipe mould after taking out shall be cooling slowly at room temperature and not allowed cooling rapidly at the vent. The heat preservation measures shall be made in the northern winter season for mould≥Dn600 to prevent the pipe mould from deforming and cracking due to the change of stress.
The rust removal shall be made if the casting pipe mould rusted, and then the position, degree and type of the defect should be identified by visual inspection and hand feeling so as to choose the maintenance mode accordingly.
If the small cracks appear in the inner hole of the pipe mould or only the inner hole pitting point have been worn out after using, the inner hole of pipe mould shall be performed grinding and then peening.
If the damaged part is within 700mm at both ends or at both ends face, the damaged part can be turned by lathe, then performed build-up welding, turning, grinding and peening.
If the damaged part is on the OD, the part shall be turned, and then performed build-up welding, turning, grinding and peening.
If the damaged parts are deep in the inner hole(all the inner holes produce thermal fatigue cracks or long scratches, etc.) or the size of the inner hole is out of tolerance, the crack layer or scratches can be removed by deep hole boring machine, and then welding is carried out on special deep hole welding equipment. Annealing shall be performed to remove the internal stress, and then the mould shall be returned to deep hole boring, grinding and peening.
After completion of the above operation, the pipe mould shall be final inspected and tested. Only it can be used again after qualified.
