【作者】 王海文；

【导师】 杨坤怡；

【作者基本信息】 西南交通大学 ， 机械制造及自动化， 2011， 硕士

【摘要】 铁路用钢轨材料通常为U71Mn高锰钢,硬度高,切削困难。因长期反复轮轨碾压,产生了波磨、轨面剥离、擦伤、飞边等钢轨伤损类型,这些伤损在钢轨修复成型中由于冷作硬化的缘故,钢轨切削更加困难。旧钢轨属于典型的难加工材料。目前,高锰钢钢轨再修复成型中切削用量的选择往往依靠经验进行。依靠经验法选择的切削用量数值往往不合理,是造成刀具磨损加剧,切削效率低下的重要原因。论文在对高锰钢材料特性分析研究的基础上,首先对影响切削的刀具材料、刀具几何角度作了论述说明,其次对高锰钢切削时的切削力和切削温度进行了分析和总结,目的是为后面章节高锰钢铣削用量优化作理论基础。最后结合正交试验原理,采用多因素正交回归试验法,依据硬质合金刀具铣削高锰钢的的试验数据建立了刀具寿命公式,并把此公式作为BP-GA优化模型中的约束条件之一。建立了高锰钢铣削加工中切削用量优化的数学模型,通过对切削过程中影响切削结果的各个因素分析,确定目标函数和约束条件。结合神经网络和遗传算法(BP-GA)来实现对目标问题的优化,最终对优化结果进行了实验研究和验证,表明建立的优化数学模型和采用的遗传算法具有生产实用性,为高锰钢的铣削用量优化提供了应用指导。更多还原

【Abstract】 The material of railroad rail is the U71Mn High Manganese Steel (HMS) with high hard hardness and cutting difficulty. Due to long term wheel-rail relationship, the railroad rail emerges various damage. It is very difficult to cut the used rail with strain hardening, the used rail is a typical difficult machining materials.At present, the selection of the HMS cutting parameters usually depends on experience it does not make sense that the selection of cutting parameters is by experience. alsoit is the main cause that leads to wear and damage of the tool and low efficiency.Based on the analytical research of HMS characteristics, firstly, we discuss that tool material and cutter geometrical angles effect on the cutting. Secondly, we analyze and summarize the cutting force and cutting temperature in the machining process. Lastly, we get the tool life empirical formula of the milling HMS by means of multi-factors orthogonal experiment design, the formula is as a constraint condition in the BP-GA optimization modelWe establish the mathematical model of optimization parameter, through analyzing the each factor which affects the cutting results in the process, it has obtained that the constraint conditions and optimization function. Ultimately, We work out the practical problem by means of BP Neural Network and Genetic Algorithms(BP-GA). The mathematical model of machining the High Manganese Steel and the Genetic Algorithm in this paper is useful to production, which make the theoretical basis and application guidance for machining High Manganese Steel.更多还原