薄壁管数控弯曲截面畸变的实验研究

截面畸变是薄壁管小弯曲半径数控弯曲成形容易出现的成形缺陷之一。文章采用实验法,研究了芯头个数、芯棒伸出量、弯曲角度、压块润滑状态、相对弯曲半径、材料等因素对截面畸变的影响;并提出了减小截面畸变的有效措施。结果表明,增加芯头个数与芯棒伸长量都能减小弯管的截面畸变,但两者都导致弯管壁厚减薄量增大;随着弯曲角度的增加,截面畸变越严重,相对弯曲半径越小,无芯棒与芯头支撑段弯管的截面畸变愈严重;在压块无润滑情况下,弯管的截面畸变和壁厚减薄量都小,并且在同等弯曲条件下,1Cr18Ni9Ti弯管的截面畸变小于LF2M弯管。

Experimental study on cross-section ovalization of thin-walled tube in NC bending process

Cross-section ovalization is one of the flaws in the thin-walled tube NC bending process.The effects of some parameters,such as mandrel ball numbers,mandrel extension length,bending angle,lubrication condition of pressure die,relative bending radius and material,on ovalization have been investigated by experimental method,and the effective methods to reduce the ovalization are proposed.The results show that increasing the ball numbers and mandrel extension length may reduce the ovalization,but leads to more remarkable wall thinning; the ovalization becomes more severe with the larger bending angle; the smaller the relative bending radius,the larger the ovalization is;the ovalization and wall thinning degrees are both smaller in the case of pressure die with dry lubricant; and under the same bending condition,the ovalization of LF2M tube is larger than the one of 1Cr18Ni9Ti tube.