锥孔锻件自动化闭式热挤压工艺

Automatic closed hot extrusion process of cone hole forging

针对锚固装置中的锚套典型件,设计了自动化热挤压工艺。试生产中出现锻件质量不稳定和模具寿命太低等问题,导致难以实现自动化生产。质量不稳定的表现是锻件同轴度超差且无规律,模拟分析了预锻同轴度对成形凸模等效应力和偏移量的影响,并通过提高坯料尺寸精度和调整镦粗高度解决了同轴度的问题,使锻件同轴度从最大Φ0.86 mm减小到Φ0.4 mm以内,确保了锻件质量稳定合格。成形凸模失效的表现是磨损,模拟分析了不同材料、润滑系数、凸模长径比对模具磨损量的影响,并通过实验确定:润滑剂采用水基石墨,凸模材料采用3Cr2W8V钢,将模具寿命从1500件提高到10000件以上,可以连续生产20 h以上。最终实现班产不换模具且无废品,达到自动化生产的要求。

For the typical parts of anchor sleeve for anchoring device,an automatic hot extrusion process was designed. The instable forging quality and short die lifetime during the production hindered the realization of automated production. The performance of quality instability was the coaxiality of big tolerance and not regular in the forging. Then,the influences of pre-forging coaxiality on the equivalent stress and offset of forming punch were simulated and analyzed. Therefore,the problem of coaxiality was solved by improving the blank size accuracy and adjusting the upsetting height,and its coaxiality was reduced from Φ0. 86 mm to Φ0. 4 mm or less to ensure the stable forging quality.However,the forming punch failure displayed the wear,and the influences of different materials,lubrication coefficient and punch length to diameter ratio on the die wear were simulated and analyzed. The experiment results show that the die life is increased from 1500 pieces to10000 pieces with water-based graphite lubricant and punch material 3Cr2W8 V steel,and the continuous production is up to 20 hours at least.Finally,a day without changing dies and defects unqualified forgings can be realized to achieve the requirements of automated production.