Research and application of precision forging forming process for flat thin flash of automobile disc steering knuckle

Abstract

The steering knuckle is the important safety part of commercial vehicle, the structure is more complex as the performance improved. In this paper, a kind of disc-type steering knuckle with complexity up to level S4 is studied, and a precision forging process is proposed to change the traditional horizontal open pre-forging and large flash final forging into semi-closed flat thin flash pre-forging and semi-closed flat thin flash final forging. Based on the analysis of mechanism and effect of the classical forming theory on the flat thin flash, the equivalent stress, equivalent strain and temperature distribution field as well as the force formation curve and deformation law are obtained by means of thermal-mechanical coupled finite element simulation analysis, and the correctness of the process scheme is verified. The precision forging of steering knuckle has been successfully developed on the program controlled hammer and CNC electric screw press, the results are consistent with the simulation results. The material utilization rate of the new process is 88%, which is 16% higher than that of the traditional process, with better quality and stronger bearing capacity. In recent years, the company has built four automatic production lines with CNC electric screw press as main equipment, with robot operation and online detection of hot forging, it has realized mass production of flat thin flash precision forging of A161 disc-type knuckle series product.