机械式双金属复合管基/ 衬管之间为过盈贴合，衬管较薄且刚度较差，若工程应用中使用不当，易出现双金属复合管衬管鼓包失稳。从双金属复合管衬管鼓包失稳的机理研究，给出了适用于复合管衬管鼓包临界载荷估算的经验公式和发生衬管鼓包的力学条件。根据发生衬管鼓包的力学条件结合复合管设计、生产和使用过程，分析了可能影响复合管鼓包的主要因素。经理论分析与试验验证得出:双金属复合管结构设计及基/ 衬管结合强度值不合理，会导致衬管鼓包临界载荷降低，基/ 衬管之间进水且在高温下使用，衬管出现贯穿性缺陷导致输送介质进入基/ 衬管间隙是双金属复合管衬管鼓包失稳的主要因素。

Interference bonding is between the base pipe and the liner pipe of the mechanically lined pipe, and the liner pipe is relatively thin. If it is used unsuitably in the project, it is possible that buckling and instability would appear on the liner pipe of the bimetal lined pipe. Through the mechanism analysis on the buckling and instability of the liner pipe of the bimetal lined pipe, this paper indicates mechanical condition of the buckling occurrence on the liner pipe and the empirical formula, which is suitable for the critical load estimation on the liner pipe buckling. The principal factors that might influence the buckling of the lined pipe are analyzed according to the mechanical condition of the buckling occurrence, together with the design, production and using process of the lined pipe. Based on the theoretical analysis and empirical testing, this paper concludes that unreasonable design of the lined pipe structure and bonding strength between the base and liner pipe could lead to the reduction of the critical load of the liner pipe buckling. At the same time, the principal factors of the liner pipe buckling and instability are the water penetration between the base and liner pipe while using under high temperature, the appearance of penetrating defects on the liner pipe, which causes the transporting stuff to enter the gap between the base and liner pipe.