【作者】 张文超；

【导师】 陈文琳；

【作者基本信息】 合肥工业大学 ， 材料加工工程， 2010， 硕士

【摘要】 随着钢丝制品行业的快速发展,钢丝韧性性能越来越受到人们的关注。扭转性能是钢丝的重要机械性能指标之一,用以表征材料的韧性性能。对扭转性能的研究是提高钢丝综合力学性能的关键。本文以冷拔钢丝为研究对象,主要研究内容如下:首先,分析钢丝扭转变形机理、异常断口、材料组织结构、表面质量及残余应力测量。通过宏观和微观综合分析,钢丝表面轴向残余应力值过大是影响钢丝扭转性能降低的主要因素。其次,根据有限元理论,建立钢丝拉拔的三维模型,在实际生产的条件下采用物理测量验证有限元模型可靠性。分析金属的流动特点及钢丝残余应力的分布规律。最后,引入混合优化方法,利用有限元模拟和神经网络建立正确的描述拉拔参数与钢丝表面轴向残余应力关系的映射模型,采用遗传算法进行优化设计,优化钢丝拉拔过程参数。通过对冷拔钢丝扭转性能研究,混合优化后钢丝表面的轴向残余应力降低67.6%,优化效果明显。使钢丝表面的裂纹不易在轴向应力下扩展破坏,因此提高了冷拔钢丝的扭转性能,保证钢丝的综合力学性能,为同类问题的解决提供了借鉴。更多还原

【Abstract】 With the rapid development of steel wire industry, more and more attention has been paid to the toughness of steel wire. Torsion performance is an important mechanical indicator, which is often used to describe the material toughness properties. Therefore, the research of torsion is the key to improve its comprehensive mechanical properties.In this paper, cold drawn steel wire is selected as the research object, and the main research contents are as follows:Firstly, the wire torsion deformation mechanism, abnormal fracture, material organizational structure, surface quality and residual stress are investigated in detail. By macro and micro analyses, the primary factor of degrading torsion performance is oversized axial residual stress in the surface.Secondly, according to the finite element theory, the three-dimensional modeling of wire drawing is established, and the finite element model is verified by using physical measurements in the actual production conditions. Metal flow characteristics and residual stress distribution in the steel wire are finally analyzed explicitly.Last, hybrid optimization method is introduced in present work. Finite element simulation and BP neural network are combined together to build the non-linear mapping relations between residual stress and forming parameters. During the process of optimization, genetic algorithm is used to obtain the wire drawing process parameters.Through studying the torsion performance of cold drawn steel wire, the axial residual of steel wire surface is forced to be decreased by 67.6%, and hybrid optimized effect is fully perfect. The defects of steel wire surface do not expand easily under the residual stress. Therefore, Torsion performance is enhanced greatly, and the comprehensive mechanical property is guaranteed. It also provides helpful references for the similar problems.更多还原