【作者】 赵熹；

【导师】 张治民；

【作者基本信息】 中北大学 ， 火炮、自动武器与弹药工程， 2014， 博士

【摘要】 炮弹是战争中消耗量最大、杀伤性能最高的武器，同时也是军工生产中批量最大的产品。大口径弹体毛坯为典型的变壁厚筒体构件，其传统生产方式为：采用“冲压-引伸”工艺形成直壁筒体构件，然后通过机加工的方法切削出不同的壁厚。采用该种方式进行生产带来材料利用率低、加工时间长、刀具消耗量大、生产成本高等问题。针对这一情况，本文提出了辊挤-引伸的新工艺，能够实现变壁厚筒体构件的塑性成形，达到少切削或者无切削的目的，不但可以大大提高了材料利用率和生产效率，还能够使金属流线沿工件轮廓合理分布，提高零件的力学性能。针对50SiMnVB高强度合金钢，借助于热模拟压缩实验、光学金相显微分析、硬度测试等研究手段，系统研究了不同变形参数下材料的流变行为，构建了该种材料的J-C本构模型，并对本构方程经验参数C进行了修正。获得了50SiMnVB基于动态材料模型的热加工图，发现该种材料具有三个峰值能量耗散区域：(I)650～750℃，0.01s1(II)800～900℃，0.001s1，(Ⅲ)1050～1150℃，0.01s1～0.1s1，结合生产实际情况，建议优先选择变形温度为1050～1150℃，应变速率为0.01s1～0.1s1范围内的工艺参数，为该种合金钢的热塑性加工提供理论依据。在辊挤-引伸成形的原理研究中，首先分析了工件实现端部咬入的条件，推导了极限咬入角的计算公式，并得出了稳定辊挤条件；其次分析摩擦系数对咬入条件的影响，给出了摩擦系数的近似计算公式；然后分析了辊挤过程中金属的流动规律，对前滑问题进行了重点研究，根据辊轮凹槽的形状特征推导了辊挤的前滑公式；最后给出了辊挤力的计算公式。根据对挤压件尺寸精确控制的原则，完成辊轮的凹槽设计，制定了辊轮主要结构参数的设计准则；根据有限元数值模拟结果，采用中心复合设计的方法完成了辊轮结构参数优化的实验设计，建立了回归模型，并进行了响应面分析；设计了加权渴望函数的综合评定因子，并计算出了的最优辊轮结构参数：轴线距离189.7475，飞边槽顶角29.9495，辊轮宽度130.1515。在此基础上，完成了辊挤-引伸装置的设计与制造，并对原有生产线进行了改造。通过有限元数值模拟，分析了工艺参数对场变量分布均匀性的影响，并以此为依据选取了工艺参数设计变量；从控形与控性相结合的角度选取目标函数。采用BBD实验设计的方法制定了各因素不同水平下的实验方案，将响应曲面法应用到层次分析中，得到了三个目标函数的分配权重；依据灰色关联度分析结果，获得了最优的工艺组合：T=950℃， V=32mm/s，μ=0.2。对辊挤-引伸成形方案和工艺参数优化结果进行了实验验证，结果表明：与传统工艺相比，采用辊挤-引伸工艺可使弹体毛坯材料利用率提高9.8%，生产效率提高一倍以上，降低了综合生产成本，实现了节能降耗，达到了预期研究目标，为辊挤-引伸技术的推广应用提供了有力的支撑。更多还原

【Abstract】 The production of shells is one of the largest groups of products in militaryproduction.Shells have the largest consumption in the war as the main body of conventionalweapons. The large caliber projectile blank is typical variable wallthickness ofcylinder components. The traditional mode of producing is "stamping-stretch" to form thestraight wall cylinder components, and then cut out different wall thickness, using the methodof machining. This method leads to low material utilization ratio, long processing time, largecutting tool consumption, and high cost. In this paper, in order to solve these quetions, therolling-extrusion and drawing technology is put forward to make the parts with plasticforming methods, with less cutting or no cutting, which not only can greatly improve thematerial utilization and production efficiency, also can make the reasonable distribution ofmetal flow along the contour and improve the mechanical properties of the parts.50SiMnVB alloy steel was analyzed in this paper by means of isothermal compression,optical microscopy, scanning electron microscopy, hardness testing. The deformation behaviorof the alloy steel with different deformation parameters was systematically studied, and theJ-C constitutive model of the alloy steel under the different stress states was established.Based on the dynamic material model, the steel’s two-dimension processing map was created,which showed that the alloy stell has three peak energy dissipation areas:(I)650～750℃，0.01s1(II)800～900℃，0.001s1，(Ⅲ)1050～1150℃，0.01s1～0.1s1.According to theactual production situation，the best choice of process parameters was within temperature1050~1150℃and strain rate0.01~0.1.This provides the reference for choosing theforming parameters.In the study of the principle of the rolling-extrusion and drawing, firstly, the end biteconditions of the workpiece were analyzed, and the formula of limit bite angle and thestability rolling-extrusion conditions were deduced; Secondly, the impact on the biting condition of friction coefficient was analyzed, and the approximate formula of the coefficientof friction was got; the analysis of the metal flow law in the process of rolling-extrusion wasdone. A research is focused on the forward slip and the formula was deduced, according to thecharacters of the shape of the roll grooves. At last, A calculation formula of rolling-extrusionforce was given.The roll grooves were designed based on the principle of precise control on parts size, andthe design criterias of main structure parameters of the rollers were made. According to theresults of finite element numerical simulation, the optimization experiment on roller structureparameters was worked out; using the method of central composite design, and the regressionmodel was established. By response surface analysis and comprehensive evaluation based onthe weighted desire function factor, the optimal roller structure parameters were obtained: theaxis distance189.7475, the apex angle of flash gutter29.9495, the roller width130.1515. Onthis basis, the rolling-extrusion and drawing equipment was designed and manufactured.What’more, and the transformation of the original production line was finished.Through the finite element numerical simulation, analysis of the process parameters onthe distribution uniformity of the field variables was done. The design variables were selected,with impact assessment on the workpiece deformation uniformity as a reference, and theselection of objective function was done with a combined way of shape controland performance control. The experimental scheme of each factor under different level wasdesigned by using the method of BBD, and the three objective function distribution of weightwere got, through the application of response surface method on the analytical hierarchyprocess. The results of grey correlation degrees analysis showed the optimal combination ofprocess: T950C, V32mm/s，0.2.Experiments were carried out to verify the feasibility of the rolling-extrusion and drawingprocess and the correctness of the optimization of process parameters. The results showed thatas compared with the traditional process, the rolling-extrusion process can make the materialutilization rate of projectile blanks be improved9.8%, and make the production efficiency be improved by more than double, along with reducing of the overall production cost, saving ofenergy and reducing consumption, which meet the expected research goal, and powerfullysupported the application of the rolling-extrusion technology.更多还原