求翻译：弯管是一种空间曲面构件，在弯管成形制作过程中，外弧段受拉伸而使管壁减薄、内弧段受压缩使管壁增厚，易出现截面椭圆化和壁厚不均现象。是什么意思？

Pipe is a curved surface elements, in the pipe forming the production process, leaving the outer arc wall thinning under tension, within the arc by compression so that the wall thickening, and prone to cross-section elliptical wall thickness is not both phenomena.

syphon is a spatial curvature components, the syphon molding production process, in paragraph one, the tensile and the pipe wall thinner section of the ARC, in compressed the pipe wall thickening, prone and a wall thickness of sectional oval.

The elbow piece is one kind of space-like surface component, in the elbow piece forming manufacture process, outside the segmental arc is stretched causes the pipe wall to attenuate, in the segmental arc is compressed causes the pipe wall accumulation, easy to appear the section ellipse rounding and

Elbow is a surface component, making in pipe bending forming process, the outer arc stretching and the pipe wall thinning, arc compression inside tube wall thickening, susceptible to uneven sections and wall thickness of the ellipse.

Elbow is a surface component, making in pipe bending forming process, the outer arc stretching and the pipe wall thinning, arc compression inside tube wall thickening, susceptible to uneven sections and wall thickness of the ellipse.