离心泵壳体件的修复(国外英文资料).docVIP

离心泵壳体件的修复(国外英文资料) Repair of centrifugal pump housing Centrifugal pump shells are usually cast in grey cast iron. Grey cast iron has good casting and cutting performance, the price is cheap, but high carbon content, large material brittleness, containing impurities, and tensile strength is low, the lack of plasticity and toughness, in the process of transportation, running and so on, is likely to produce cracks, and even local damage. A common method for repairing shell parts (1) thermal rehydration The thermal welding process is complicated, which is suitable for large parts with large force or change of shape. Before the soldering, place the pump shell in the cast mould of the water resistant brick, and then put the yellow sand in the inner surface, and place charcoal or coke in the surrounding area, warm up the pump shell, and the time is 2-5h. Warm up the temperature gradually and gradually heat up to 500. The pump case is red through the left, and then the pump shell must be soldered, the rest is covered with asbestos, and then welded with cast iron electrode or stainless steel electrode. After welding, the pump shell is naturally cooled in the furnace, and the internal stress is retreated. (2) cold rehydration Cold repair welding technology, need not special preheating before welding, welding without heating, can omni-directional welding, can simplify the process, save the heating equipment, reduce cost and improve the welding conditions, welding pieces of basic deformation and residual stress is small. The cold repair process is introduced as follows. Welding groove. At the end of the pump shell crack front 5mm, the crack hole of ping Smm and deep l5-20mm. The crack is cut into v-shaped or u-shaped groove with Angle, deep 10-20mm, wide 15-20mm, and the groove should be smooth and clean. The surface of the metal surface is worn by the width of 1OOmm in the weld area of the groove. The welding materials are made of nickel-iron alloy welds, and the welds shall b