底孔直径对1100铝合金内螺纹冷挤压过程的影响

Effect of hole diameter on cold extrusion process of 1100 aluminum alloy internal thread

冷挤压成形内螺纹具有加工效率高、成本低、牙形流线分布合理、螺纹强度高等特点.底孔直径是冷挤压内螺纹加工过程中的关键工艺参数.研究了工件底孔直径对1100铝合金冷挤压内螺纹性能的影响,利用DEFORM-3D有限元软件模拟1100铝合金M12×1.25 mm螺纹孔冷挤压过程,通过分析不同底孔直径的等效应力应变、扭矩及牙高率的变化,探索最佳底孔直径,并进行实验验证.结果表明:在内螺纹冷挤压数值模拟过程中,等效应力与等效应变变化趋势一致,发生在挤压丝锥与铝合金挤压摩擦的工作区域,说明挤压丝锥的结构也是影响内螺纹冷挤压变形的因素.随着底孔直径的增大,加工过程中的扭矩及牙高率都呈降低的趋势,扭矩及牙高率的有限元模拟结果与实际测量结果吻合较好,验证了有限元模拟的正确性与可靠性.综合考虑成形过程的影响,最佳底孔直径为11.45 mm.

Cold extrusion internal thread has the characteristics of high processing efficiency,low cost,reasonable distribution of thread streamline and high thread strength.The hole diameter is the key parameter in the cold extrusion process of internal thread.The influence of workpiece hole diameter on the cold extrusion internal thread of 1100 aluminum alloy was studied.DEFORM-3D finite element software was used to simulate the process of cold extrusion of 1100 aluminum alloy M12 × 1.25 mm threaded hole.By analyzing the changes of equivalent stress-strain,torque and tooth height ratio under different hole diameters,the best hole diameter was explored and tested.The results show that in the process of numerical simulation of cold extrusion of internal thread,the change trend of equivalent stress is consistent with that of equivalent strain change,which occurs in the working area of extrusion friction between extrusion tap and aluminum alloy.It shows that the structure of extrusion tap is also the factor affecting the cold extrusion deformation of internal thread.With the increase of the hole diameter, torque and tooth height ratio of the thread all decrease. The results ofthe finite element simulation of torque and tooth height rate are in good agreement with theactual measurement results, which verifies the correctness and reliability of the finite elementsimulation. Considering the influence of forming process, the best hole diameter isФ11. 45 mm.