Justification of recommendations for the design of technological processes for manufacturing and repairing connecting elements in automotive exhaust systems

Abstract

Vehicle exhaust systems are damaged by corrosion and mechanical stress. Connection zones at diameter transitions, especially those welded or tensioned, are particularly vulnerable. Increasing wall thickness can improve wear resistance and extend repair intervals, but this also adds weight to the components and the vehicle, which is not desirable.

Therefore, the current task remains to increase the wear resistance and reliability of components with a simultaneous reduction in the weight of the vehicle without the use of expensive materials.

This article presents a method for manufacturing and repairing exhaust system connecting pipes by forming bells with minimal end thinning. It offers general recommendations for designing the manufacturing and repair processes. Due to the complexity, time requirements, and high cost of stamping equipment, careful process development and selection of the most technically and economically effective approach are essential. Even minor changes in the process often require redesigning or producing new dies, which can be time-consuming and costly.

Recommended distribution coefficients are provided for steel 12X18N10T and aluminum AD1, both commonly used in automotive exhaust units. The suggested lubricants effectively reduce friction between the blank and tools during plastic deformation as the blank diameter increases. These lubricants are readily available and have proven effective in various applications.

The proposed method of dispensing with an asymmetric tool increases the thickness of the edge part compared to classic dispensing. This happens due to the appearance of tangential stresses that unload the deformation center. Because of this unloading, tangential normal tensile stresses are reduced, which increases the thickness of the finished product. The route for manufacturing a bell on a pipe blank includes an additional transition compared to classic dispensing.

Key words: exhaust system, repair, manufacturing, car, plastic deformation, bell, dispensing.