Application of pulsating hydroforming in manufacture of engine cradle of austenitic stainless steel

Abstract

The effects of tube bending, preforming and subsequent hydroforming on formability of austenitic stainless steel in manufacture of engine cradle were studied in present study. Wall thickness distribution, surface quality and cross section distortion after tube bending were analysed. The results showed it can obtain high forming quality and dimensional accuracy when tubes are filled with 0.7 mm diameter steel balls during bending process. It is more important that pulsating hydroforming can effectively improve the formability of final products which have apparent non-uniform deformation due to the springback after bending. Applying pulsating load with large amplitude can achieve a more uniform deformation with a more homogeneous thickness distribution beneficial for preventing excessive local thinning and an excellent die filling performance for tube hydroforming.