Failure analysis and improvement method of twist-pressure isothermal composite forming die for cup

Abstract:

To solve the forming die' s early failure of 7A60 aluminum cup in the twist-pressure isothermal composite formingexperiment,withthe use of finite element software DEFORM, a detailed discussion and analysis of the cause of failure is studied in terms of the technical characteristics, stress distribution and mold structure. The results show that the main reasons which cause the early rupture at the corner of the die arethe stress concentration, hot-cold cycle thermal stress and the oxidation of high-temperature mold. Then based on thetheory of “no crack first division”, the structure of the die is improved. Finally, the results show thatthe improvements of die effectively avoid the stress concentration and reduce the equivalent stress extremes by 30%.The metal flow lines are visible on the surface of cup with no obvious defects.