1. The cylinder is cast, and the cylinder is subjected to aging treatment after leaving the factory, so that the internal stress generated by the cylinder during the casting process is completely eliminated. If the aging time is short, the machined cylinder will be deformed in the future.
2. The force of the cylinder during operation is complicated. In addition to the static pressure of the gas inside and outside the cylinder and the weight of each component contained in it, it also bears the reaction force against the static part when the steam flows out of the vane, and The force acting on the cylinder under various hot and cold conditions of the connecting pipe, under the interaction of these forces, the cylinder is prone to plastic deformation and leakage.
3. The load increase and decrease of the cylinder is too fast, especially the rapid start, stop and the change of the working condition, the temperature change is large, the way of the warm cylinder is not correct, the insulation layer is opened too early during the maintenance, etc., and is generated in the cylinder and the flange. Great thermal stress and thermal deformation.
4. The cylinder generates stress during the machining process or after repair welding, but the cylinder is not tempered to eliminate the cylinder, resulting in large residual stress in the cylinder, resulting in permanent deformation during operation.
5. During the installation or overhaul process, due to the maintenance process and maintenance technology, the expansion gap of the inner cylinder, cylinder partition, diaphragm sleeve and steam jacket is not suitable, or the expansion gap of the hanger pressure plate is not suitable. After that, a huge expansion force is generated to deform the cylinder.
6. The cylinder sealant used is of poor quality, too many impurities or the wrong type; if there are hard impurity particles in the cylinder sealant, it will make the sealing surface difficult to tightly bond.
7. The clamping force of the cylinder bolt is insufficient or the material of the bolt is unqualified. The tightness of the cylinder joint surface is mainly achieved by the tightening force of the bolt. The thermal stress and high temperature generated when the unit starts or stops or increases or decreases the load will cause the stress relaxation of the bolt. If the stress is insufficient, the pre-tightening force of the bolt will gradually decrease. If the bolt material of the cylinder is not good, the bolt will be elongated under the action of thermal stress and cylinder expansion force during long-term operation, plastic deformation or fracture will occur, and the tightening force will be insufficient, causing the cylinder to leak.