求翻译：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？

Forming in the pipe production process, leaving outside the arc wall thinning under tension, within the arc by compression so that the wall thickening, and elliptical cross-section prone to the phenomenon of uneven thickness.

In syphon took shape during the production process, from paragraph one by the tensile and the pipe wall thinner paragraph one, in the compression so that the wall thickness, increased cross-sectional elliptical, prone and wall thickness.

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 the wall thickness uneven phenomenon.

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.

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.