Abstract:Based on Dynaform

a finite element model of hydroforming for four way pipe was built. Through the initial feed rate

initial internal pressure

and the intermediate pressure were selected as the design variables

taking the minimum and maximum wall thickness of the post forming for tube as design aim.Based on Box Behnken Design and response surface method

the response surface model was established for the goals of minimum and maximum wall thickness of tube

the effects of various parameters on the forming tube by numerical simulation was studied

and the optimal parameters of the model was determined through variance and regression analysis. The result of model’s predicted factor through finite element simulation

compared with the result of the model

the error rate was less than 1 percent

therefore the reliability of the model was verified. The results showed that high quality forming process parameters four tube part could be quickly got through response surface method and numerical simulation.