Q460高强度钢内螺纹冷挤压试验研究

Experimental Research on Cold Extruding of Internal Thread in Q460 High-strength-steel

传统的内螺纹冷挤压加工仅适合于强度低、塑性好的非铁金属以及低碳钢的加工,而飞机、高速列车等关键部件的内螺纹需要采用高强度钢进行加工。针对高强度钢内螺纹的冷挤压加工过程中,润滑液的选择、挤压速度、工件底孔直径、挤压次数等加工条件对丝锥的磨损与折断以及内螺纹的加工质量影响很大的问题,通过对Q460高强度钢内螺纹冷挤压过程的试验研究,分析了润滑液、工件底孔直径、挤压速度与挤压次数对挤压扭矩与挤压温度的影响,并优选工艺参数获得理想的内螺纹,为进一步提高内螺纹的表面质量和疲劳性能提供新的依据。试验结果表明,Q460高强度钢内螺纹冷挤压加工宜采用一次成形工艺,选用黏度值在10～12的流体薄油膜润滑液进行冷却润滑,工件底孔直径最佳取值范围在21.20～21.30 mm,一般选取的挤压速度为30～60 mm.min–1。

Traditional cold extrusion process of internal thread is only fit for processing low-intensity and high plasticity metals such as non-ferrous metals and low-carbon steel.But the internal thread of the key parts such as airplane and high speed train is processed with high-strength steel.During cold extruding high-strength steel internal thread,the effects of lubricant,workpiece bottom hole diameter,extrusion speed and extrusion times on wear and fracture of the tap and manufacturing quality of the internal thread are great.The process of cold extrusion of Q460 high-strength steel internal thread is studied through experiments.The effects of lubricant,workpiece bottom hole diameter,extrusion speed and extrusion times on extrusion torque and extrusion temperature is analyzed.And the ideal internal thread is obtained through optimizing technological parameters.It provides a new basis for improving the surface quality and the fatigue property of internal thread.The test results show that Q460 high-strength steel internal thread is better formed by cold extrusion through one-step forming technology.The fluidic thin film lubricant whose viscosity number is between 10 and 12 is selected.The best range of workpiece bottom hole diameter is between 21.20 mm and 21.30 mm.And the generally selected extrusion speed is between 30 and 60 mm·min–1.