Research on integral hydro-mechanical forming process of symmetrical structure pipe with large cross-section changing rate
To solve the manufacturing problem of multiple forming passes in integrated forming of an automobile exhaust liner,the sym-metrical structure at the circular cross-section(B-type)was proposed which is different from the design idea of traditional symmetrical structure at the traditional flattening feature(A-type),which were formed by hydro-mechanical forming process.By comparing the form-ing passes and part quality,the advantages and disadvantages of the two kinds of symmetrical structures workpiece were analyzed.It is found that because of the cracks in the round corners of the A-type workpiece during the one-step forming,it is necessary to adopt multi-step forming to realize it.The B-type workpiece has good forming effect with one-step forming.The maximum wall thickness reduction rates of the A-type structure workpiece after multi-step forming and the B-type workpiece after one-step forming are both less than 25％.However,compared with the A-type symmetrical structure workpiece,the wall thickness reduction rate at the round corner of B-type work-piece is lower,and the forming effect is better.The number of mold of B-type structure is reduced from three sets to one set.Through the reasonable part structure design,the structure breaks the traditional circular section end seal design constraints,not only effectively re-duces the cost of the mold,but also improves the production efficiency,and greatly improves the part forming effect.
NETL
NSTL
万方数据
维普
