【作者】 李航；

【导师】 张连洪；

【作者基本信息】 天津大学 ， 机械工程， 2012， 硕士

【摘要】 全纤维弯曲镦锻是生产整体式曲轴的重要工艺方法。现阶段广泛应用的曲轴全纤维弯曲镦锻工艺方法主要有RR、NRR、TR和NTR等。以上工艺方法的基本原理相同，即通过镦弯复合变形实现曲拐臂的成形；其本质差异为镦弯速度搭配不同，从而产生具有优劣差异的成形效果。本文基于6G32曲轴锻件的1:24比例模型，通过数值模拟和比例模型试验，对以上四种弯曲镦锻方法进行系统的比较分析，获得镦与弯速度搭配对曲拐臂的成形效果的影响规律，为合理制定镦锻工艺提供科学依据。论文的主要研究内容和成果如下：1.为了系统地比较各种弯曲镦锻方法，分析镦与弯速度搭配对曲拐臂成形的影响规律，设计了基于6G32曲轴锻件1:24比例模型的12组镦弯速度搭配加工参数，其中RR法1组，NRR法3组，TR法1组，NTR法7组。2.应用塑性有限元方法对所设计的加工参数进行了数值模拟，分析对比了各组加工参数的填充效果、成形过程、锻件内部平均应力和镦锻成形力，之后运用模型试验技术对成形效果和镦锻成形力的数值模拟结果进行试验验证。结果表明：弯曲运动开始前，镦粗行程进行得足够充分，弯曲运动开始后，镦粗速度较低且呈递减趋势而弯曲速度较高，这样的镦-镦弯行程，更有利于曲拐臂的成形。更多还原

【Abstract】 The continuous grain flow upset-bending process is an important method tomanufacture solid crankshafts. At this stage, RR, NRR, TR and NTR are four kindsof upset-bending processes which are widely used. The fundamental principle of theabove processes is the same that forging the crank arm by upsetting combined withbending; but the essential difference between them on the combination of upsettingspeed and bending speed leads to different forging effect. A1:24model of thecrankshaft modeled6G32is selected to study the four upset-bending processessystematically with numerical simulation and scale model experiments. The acquiredeffect laws of the combination of upsetting speed and bending speed can provide abasis for formulating forging process reasonably. The following main contents andcontributions have been made in this article:1. In order to compare the upset-bending process systematically and analyze thelaw how the combination of upsetting speed and bending speed influences theforging effect,12groups of forging parameters are made, which is constituted by1group of RR,3groups of NRR,1group of TR and7groups of NTR.2. Plastic finite element method is selected to analyze the filling ability, forgingprocedure, internal mean stress and forging load of the12groups of forgingparameters. Then scale model experiments are carried out to validate the numericalsimulation results of filling ability and forging load. It turns out that, the forgingprocess which is beneficial to the forging effect of crank arm should be like that:Before the bending movement starts, the upsetting stroke has been long enough;after the bending movement starts, the upsetting speed is low and decreaseprogressively, while the bending speed is high.更多还原