Modelling and analysis of metal flowing behaviors in constraining ring rolling of tapered ring with thin wall and three high ribs

Abstract

Tapered ring with thin wall and three high ribs (TRTWTHR), showing complicated geometry (wall thickness is less than 4 mm and rib height exceeds 20 mm), is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin, rocket body and fuel tank because of light weight and high carrying capacity. How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve. In this work, constraining ring rolling (CRR) technique is first adopted to form TRTWTHR. However, unreasonable metal streamlines (UMS) and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR, which makes the forming quality of TRTWTHR difficult to be controlled. Faced with this difficulty, an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR. Subsequently, the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment. Then, using the established analytical model, the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed. Finally, three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur, and the mechanisms of three uncoordinated growth modes are revealed.