冷挤压, 内螺纹, 金属流动, 金属材料成形过程

The forming process of internal thread of aircraft landing gear with cold extrusion was studied. Through metallographic analysis of the material, microstructure change and deformation mechanism of crest, flank and root of the thread along the layer depth direction were obtained. The results show that the pressure on the crest of thread under the teeth of extrusion tap was relatively small, and the root was biggest. When the metal flows to the crest, the resistance is smallest.In the extrusion processes, the hardness and the intensity of the material are increased significantly,and the plasticity and the toughness are decreased. It appeares work-hardening phenomenon and increases the surface texture and the mechanical strength greatly of internal thread with cold extrusion.

cold extrusion, internal thread, metal flow, metal material forming process