1.Cross-section ovalization is one of the flaws in the thin-walled tube NC bending process.

1.截面畸变是薄壁管小弯曲半径数控弯曲成容易成缺。

2.The failure of directly buried heat-supply pipeline is discussed, and the design essentials are put forward in accordance with local buckling and ovalization deformation.

2.探讨了直埋供热管道失效,针对局部失稳和椭圆化变,提了设计要点。