借助有限元软件ABAQUS6.5模拟研究20碳钢作基管、316L不锈钢作内衬管的双金属复合管的拉拔成形过程,分析稳定拉拔阶段成形区内轴向、径向和环向应力的分布,找出拉拔后衬管出现横裂、纵裂及模具受磨损的原因,探讨拉拔力和内外管间残余接触压力的分布规律.通过正交实验法进一步研究拉拔参数(模具锥半角α、过渡圆弧半径r、定径带长度l、摩擦因数μ、拉拔速度v、模具直径d)对拉拔20/316L双金属复合管的影响,采用极差和方差分析法对模拟结果进行分析,得到复合管在最大残余接触压力条件下的最优拉拔工艺参数(α=11-、r=3 mm、l=7 mm、μ=0.05、v=0.03 m/s、d=17.3 mm)及各因素对分析指标的影响规律.在此基础上对优化方案进行数值模拟,模拟结果表明了正交实验对拉拔复合管参数优化的有效性.应用拉拔试验表明,参数优化后的硬质合金拉拔模具的工作寿命比未优化前硬质合金模具的工作寿命高出6倍.%By means of the finite element analysis software ABAQUS6.5, a drawing forming process of bimetal-lined pipe made of 20 carbon steel as the base tube and 316L stainless steel as the liner tube was simulated to analyze the axial,radial and hoop stress distributions in the forming zone during the stable drawing stage. The reasons of transverse and longitudinal crack on the liner tube and die wear were found. The distributions of drawing force and residual contact pressure between the inner and outer pipe were discussed. The effects of drawing parameters(the semi-angle of drawing dies a, the transition arc radius r, the length of bearing part l, the friction coefficientμ, the drawing velocity v, the diameter of drawing dies d)on drawing 20/316L composite tube were investigated by using orthogonal experiment. The optimal drawing parameters (a=11°, r=3 mm, l=7 mm, μ=0.05, v=0.03 m/s, d=17.3 mm) under the maximum residual contact pressure and the influence of factors on analysis indexes were obtained according to the simulation results by the methods of range analysis and variance analysis. Then the drawing process was further studied by using these optimal parameters, and the results confirmed the effectiveness of the orthogonal experiment on optimization of drawing composite tube parameters. Compared with the non-optimized parameters cemented carbide drawing dies, the application experiment result shows that the working lifetime of the optimal cemented carbide drawing die can be increased 6 times.
展开▼
