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高温高压铸造三通在蠕变温度下长期运行后,在肩部内壁产生的裂纹具有蠕变特征,裂纹扩展过程中可能遇到芯部疏松区而加速扩展.裂纹中渗入介质后构成腐蚀电池,因而可能转变为应力腐蚀扩展.肩部蠕变开裂的主要原因是过渡园角过大而导致肩部内壁高度应力集中.修改三通结构形状和改进铸造工艺,可以降低应力集中系数和减少缩孔、疏松等缺陷,从而可提高三通的寿命.
After long-term operation of high temperature and high pressure casting tee at creep temperature, the cracks on the inner wall of the shoulder have creep characteristics, and the core may loose during the crack growth and accelerate expansion. The crack infiltrates the medium to form a corrosion battery, Which may change to the stress corrosion expansion.The main reason of shoulder creep cracking is that the transitional angle is too large to cause the high stress concentration on the shoulder inner wall.Changing the three-way structure shape and improving the casting process can reduce the stress concentration factor and reduce the shrinkage cavity , Loose and other defects, which can improve the life of three links.