Cold forging of a hollow flanged part by an unconventional extrusion method

Abstract

This paper presents a numerical analysis of a new cold forming process for a hollow part with an external flange. The following techniques were used: forward extrusion, an unconventional method of extrusion with a moving sleeve, and upsetting in a tapered die cavity. The billet (42CrMo4 steel tube) was formed at ambient temperature. The study aimed to investigate the proposed method in terms of forged part accuracy. The following are examined and discussed: material flow, process force parameters in relation to tool strength, energy consumption of individual operations, as well as the distributions of strains, stresses, temperature and Cockcroft-Latham integrals in the produced part. The study has confirmed that hollow forged parts with external flanges of relatively large diameters and heights can be cold formed in several operations using different techniques.

Ejector pin-related high-cycle fatigue fracture of the critical die corner during automatic multistage cold forging of an automotive wheel nut

“…Kolpak et al [ 24 ] studied the effects of anisotropic hardening on the predicted component properties and forming loads, including the ejecting force during cold forging, which was much affected by the influential strain hardening. Winiarski et al [ 25 ] considered the ejecting force reduction in cold forging of a hollow flanged part to increase structural integrity and minimize the damage experienced by the ejector pin. Gitschel et al [ 13 ] applied counterpressure to the material by way of the ejector pin during the cold forward extrusion to improve the product quality without any change of its shape.…”