In response to the problem that the conventional splined shaft extrusion method is short of efficiency and the forming force is large
this study adopted a new forming process
i.e.
oscillating cold extrusion. The forming experiments of splined shaft were performed and the microstructure and hardness were examined. An extrusion die whose module of gear is 1.75 and the number of teeth is 10 was used to form the workpiece. The workpiece is an AISI 1045A bar stock with a diameter of 17.9 mm. Each time when the die moves ahead 1 mm
it would moves back 0.5 mm. Different oscillating frequencies at 10
15
and 20 Hz were compared. The results showed that the forming force of oscillating extrusion decreased by nearly 25% compared with conventional extrusion. The cause of friction reduction is that the lubricant film is rebuilt between the workpiece and the die during the back stroke. Comparison of the splined shafts made by oscillating extrusion and conventional extrusion shows that oscillating extrusion provides a better surface quality of the splined shaft and the material piling is reduced. The material flow in oscillating extrusion is better than that in conventional extrusion. So the change of the diameter of the addendum circle is little and the forming accuracy is high in oscillating extrusion. Hardness test showed that oscillating extrusion can decrease the hardness of splined shaft by 10%
YAO Wenxi, QU Liangsheng. Analysis about the mechanism of “Mid-Concave” phenomenon on the surface of the gear during shaving process [J]. Journal of Xi'an Jiaotong University, 1995, 29(8): 50-58.
YANG Qinghua, CHEN Xin, MENG Bin, et al. Numerical simulation for vibration extrusion of automotive car piston pins [J]. Journal of Zhejiang University of Technology, 2013, 41(3): 317-320.
OSAKADA K, WANG X, HANAMI S. Precision forging process with axially driven container [J]. Journal of Materials Processing Technology, 1997, 71(1): 105-112.
CHRISTODOULOU N, WOO O T, MACEWEN S R. Effect of stress reversals on the work hardening behaviour of polycrystalline cooper [J]. Acta Metall, 1986, 34(8): 1553-1562.