法兰面焊接螺母冷镦成形孔口折叠缺陷的产生机理研究
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摘要
法兰面焊接螺母在实际冷镦成形中容易出现孔口折叠缺陷,采用有限元模拟分析与试验相结合的方法对缺陷进行了研究。首先结合现有设备能力及制造成本确定工艺方案;然后通过Deform-3D有限元软件对法兰面焊接螺母冷镦成形中的金属流动过程进行了动态模拟分析,得到缺陷产生的机理,并进一步对缺陷影响因素进行分析;对缺陷产生机理及关键影响因素进行了试验验证,在此基础上提出改进措施。结果表明,孔口折叠是在镦锻成形过程中,凹穴内孔圆柱面的金属流向法兰面,同时上面金属向下流动造成金属回流而成,严重时产生折叠缺陷;无法完全避免金属孔口折叠,但可通过控制成形工艺来减少折叠程度。
The orifice folding defect often happens during the practical manufacturing of flange welding nuts by cold heading molding. The FEM simulation analysis combined with experiment on the defects was adopted. At first,the process plan was made according to the equipment's requirement of the company and the cost of the product. Secondly,the metal flow process during the manufacturing of the flange welding nut by cold heading molding was dynamically studied by Deform- 3D FEM software,and the mechanism was obtained.Furthermore,the factors influencing the defect were studied systematically. At last,the mechanism and factors were tested and verified by experiments,and based on which,improvement measures were put forward. The results show that the orifice folding is formed by metal refluxing when the metal on inner cylindrical surface flows to the flange and the metal above flows down during the manufacturing by cold heading molding. If the extent of folding is serious,there will be a defect. The orifice folding is unavoidable,but the extent of folding can be controlled by optimizing the technique.
The orifice folding defect often happens during the practical manufacturing of flange welding nuts by cold heading molding. The FEM simulation analysis combined with experiment on the defects was adopted. At first,the process plan was made according to the equipment's requirement of the company and the cost of the product. Secondly,the metal flow process during the manufacturing of the flange welding nut by cold heading molding was dynamically studied by Deform- 3D FEM software,and the mechanism was obtained.Furthermore,the factors influencing the defect were studied systematically. At last,the mechanism and factors were tested and verified by experiments,and based on which,improvement measures were put forward. The results show that the orifice folding is formed by metal refluxing when the metal on inner cylindrical surface flows to the flange and the metal above flows down during the manufacturing by cold heading molding. If the extent of folding is serious,there will be a defect. The orifice folding is unavoidable,but the extent of folding can be controlled by optimizing the technique.
引文
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[8]梁建平,程旺军.基于数值模拟的锥形螺母冷镦挤成形分析与模具设计[J].锻压技术,2015,40(7):151-155.Liang J P,Cheng W J.Deformation analysis and die design of cold heading extrusion for a conical nut based on numerical simulation[J].Forging&Stamping Technology,2015,40(7):151-155.