大型管件的模压式精确缩径矫圆

提出以模压式缩径矫圆的方式代替机械扩径以减小管件椭圆度,提高其承压强度.模压式缩径矫圆采用闭合后模腔为一整圆的上、下模具对椭圆管坯进行矫圆,为减小矫圆后管坯的回弹,须使整个管坯内外壁均进入压缩塑性变形,即有足够的压缩率.本文采用小曲率曲梁平面压弯的分析方法对模压式缩径矫圆工艺进行了理论分析,推导出缩径矫圆弹复方程,该方...

Precise compression and setting round by mold for large pipes

A new method called compression and setting round was proposed to replace the mechanical expanding to reduce the ellipticity and increase the compressive strength of large pipes. The compression and setting round by mold was completed by a upper die and a lower die whose cavities could be closed to a whole round.In order to reduce the springback,the within and outside walls of the pipe must be compressed into the plastic deformation,namely,the compression rate must be sufficient.In this paper,the small curv...