Loss of stability of pipe stocks during end upset of fuel injection lines of the Common Rail systems

The article discusses one of the aspects of the production technology of high-pressure fuel pipelines of Common Rail type fuel systems. BACKGROUND: Battery-type fuel systems, often referred to as Common Rail, are becoming more widespread. The development of domestic production of such equipment requires taking into account the processes occurring during technological operations and assessing their impact on the operability of manufactured parts. Currently, most of the publications relate only to design features, and technological issues are not yet receiving sufficient coverage. AIM: The purpose of this work is to study the consequences of the loss of stability of pipe blanks observed in the manufacture of TVD, mainly TVD Common Rail systems. METHODS: The ends of the pipe blanks were landed according to various technological schemes on the die tooling and equipment used in the serial production of the theater at the Altai Precision Products Plant (UC “AZPI” LLC). Further, the experimental parts were examined in terms of the number and shape of the folds formed on the surfaces of their channels when the stability of the workpiece was lost. RESULTS: The obtained results confirmed the dependence of the number, nature and size of the folds on the technological scheme of planting. The formation of additional folds, conventionally called the second, from the top of the so–called first folds, formed directly from the surface of the channel of the pipe billet, was found. CONCLUSION: It is established that for the pipe grade of dimensions 8khvn.3.0 and 8khvn.3.6 of the STE 460 BKS type steels, the formation of annular first folds with a depth of 1 mm or more is observed during non-permanent planting. In this case, the formation of second folds from the vertices of the first folds with a depth of 560 microns and a maximum width of 0.05 mm is possible. During mandrel planting, the formation of two consecutive (along the axis of the pipe) folds is observed, differing in shape and size.