Mandrel Pull Pipe Wall Thickness

Non-mandrel drawing is a method widely used in cold drawn pipe production. It's simple, agile and efficiency. In anamorphic process of non-mandrel drawing only outside diameter is reduced, and the wall thickness being not controlled by mandrel is changed freely, which can be increased, reduced or not be changed. The wall thickness of non-mandrel drawing production is affected by many factors, so it is very difficult to be mastered. So far, internal and international cold drawn pipe production company have no settled drawn table, they commonly adopt conventional methods to arrange technology. By long-term practice, each company predominated many methods to control wall thickness, but being out of scalar, they only know the result but don't know why, which have no meaning in practice. Quantificationally to find the wall thickness mutative rules in non-mandrel drawing is of very important meaning for instructing production, increasing the size of cold drawing production, improving products precision and empoldering new products. After researching each factor of affecting non-mandrel drawn pipe wall thickness, this thesis have established theory model, found theory formula, and educed experimental data by contrastive test, corrected theory formula by adopting regression analysis, at last formed proximate formula which being used to instruct production.