增分熔融凝固加工工艺参数的探讨

对增分熔融凝固加工技术中的最主要的参数－电源电力进行了探讨,考察原电力与开始熔化时间、熔融区深度、熔融区温度、所得材料的微观组织之间的关系,并运用所得参数制得了高性能的材料。     

Analysis of a new Segmentation Intensity Ratio “SIR” to characterize the chip segmentation process in machining ductile metals

In machining, chip morphology has an important effect on several cutting parameters such as tool wear, chip flow, vibration, etc. This research work aims to analyse the chip segmentation phenomenon for ductile metals. The aeronautical aluminium alloy A2024-T351 has been selected for the study. Using Finite Element modelling, segmentation process has been analysed and quantified with a new physical parameter called “Segmentation Intensity Ratio”. The SIR parameter which leads to a better analysis of the chip morphology is defined as a ratio between the equivalent plastic strain inside and outside shear bands within the chip. Using this parameter the effect of cutting conditions and tool geometry on the chip segmentation can be clearly shown. Also the fluctuation of the contact length, the tool-chip interface temperature as well as the cutting force oscillations with respect to cutting speed are carefully discussed when segmentation occurs. A correlation between chip formation process and cutting force oscillation is established as well as a correlation between average cutting force reduction and segmentation intensity when cutting speed increases. Finally, a parametric analysis was conducted to highlight the effect of the friction on the chip segmentation intensity.     

API 20C阀体模锻件质量的过程控制

为保证阀体模锻件满足API 20C要求和产品制作过程符合规范,在以过程为方法控制质量的基础上,结合锻造工艺学,按阀体锻件的生产流程介绍了各加工环节中的质量控制措施,并阐述了每生产环节中的操作规范和质量缺陷成因。通过对过程分解的质量控制方法,能够有的放矢地进行前期质量策划和重点过程控制,利于产品质量可控。通过对不同文献资料的研究和参数优选,并结合实际操作中积累的经验,对阀体常用材质4130钢和410钢的加热规范、锻造温度范围、锻后冷却、锻后热处理工艺等进行了明确,使阀体模锻件的质量性能更易于保证。该控制措施经过长时间实践,无论产品质量还是质量可控性,都得到显著提高,具有良好的可实施性。     

管加工数控机床1850CNC参数的修改和设置方法

栅格偏移参数1850CNC是管加工数控机床控制系统非常重要的一个参数。为稳定机床的精度 ,挖掘机床的潜力 ,对1850CNC参数进行了相应的修改。简介了该参数的修改原因 ,前提条件 ,设置过程及参考点的确定原则     

电火花线切割加工Si3N4/TiN纳米复相陶瓷工艺规律的实验研究

分析研究了电火花线切割加工Si3N4/TiN纳米复相陶瓷材料时,影响加工速度和表面粗糙度值的主要因素,得出了各加工参数对加工工艺指标的影响规律,为加工时参数的选择提供了依据.     

曲面数控加工精度的研究

分析了影响曲面数控加工精度的因素,研究并提出了从数控程序设计、工艺系统和控制系统等方面提高曲面加工精度的方法。结果表明：数控加工工艺系统特性和数控系统误差是影响加工精度的重要因素,应尽量购置高精度的机床和数控系统,或采用工艺手段,或设置相应补偿参数,由系统自动补偿功能消除;程序设计的优劣也是影响加工精度的主要因素,应从刀具、加工方法、进退刀与走刀方式的选择和刀具路径规划的验证等方面采取措施,以保证曲面加工精度。     

基于LS—Dyna的板料冲裁过程仿真

利用显式动力学分析程序LS—Dyna对4mm厚Q235A板材冲裁过程进行了有限元仿真。根据仿真结果对冲裁机理、最大主应力及冲裁力的变化规律进行了分析,得出了与实际相吻合的结论,其方法和结论对冲裁工艺参数优化及相关产品研发具有参考价值。     

冷轧机组飞锯机的设计分析

介绍冷轧机组飞锯机同步机构、锯切机构、定尺机构的设计和选取，重点介绍了锯片结构参数和工艺参数的选取。     

锤锻件有效压实工艺准则及应用

对大型自由锻锤的工艺过程采用有效压实法工艺参数进行控制,可以减少镦粗次数、保证产品质量、提高产量。文中还简要阐述了工艺准则和应用实例。     

钽薄板微间隙TIG氦弧点对接焊熔池的数值分析

针对钽薄板微间隙TIG氦弧焊接方法．基于有限元分析软件ANSYS，采用数值模拟方法计算了间隙处取不同边界条件时温度场的分布。计算结果表明：间障的存在使得温度场分布不均．是熔池表面形状呈现椭圆形的一个重要因素．这种影响随焊接时间的变化更为明显。分析了间隙对熔池形状的影响，得出不同工艺参数对熔宽变化的影响规律，并分析了电孤形态差异对接头的影响。这对制定实际的TIG焊工艺具有指导意义。     

Artificial neural networks applied to spot welding process modeling

Artificial neural networks have been studied for applicability for modeling of spot welding process. Some basic concepts relating to neural networks are explained as well as how they can be used to model welding quality parameters in terms of the welding process parameter. The performance of the neural networks for modeling is presented and evaluated using actual welding data. It is concluded that neural network modeling is a good means of estimating spot welding quality on-line.     

疲劳损伤过程的热能耗散分析

利用能量作疲劳损伤基本参量,建立了疲劳损伤的能耗结构,在试验的基础上,围绕着疲劳损伤过程中的不可逆能耗分析,系统地研究了循环过程及循环内的疲劳损伤热能耗散变化规律,并寻找出疲劳过程中循环滞回能与有效能耗(储能)之间联系。     

The weldability of thermomechanically rolled S460ML steel

The way in which the metal is transferred from the electrode tip to the weld pool affects the MIG/MAG process productivity and stability, as well as the weld bead geometrical characteristics. Among the modes of metal transfer, a very important parameter to know is the value of the globular spray transition current, which occurs in a narrow band of current and causes considerable changes in the frequency and diameter of the transferred drops and, therefore, the process stability. The transition current was investigated experimentally using a high-speed video camera associated with a new proposed methodology for identifying the transition current applied to binary and ternary mixtures of O₂ and CO₂ with an Ar base.     

大型台阶圆环锻造技术研究

介绍了大型台阶环自由锻工艺参数的确定方法。指出坯料分配是工艺参数中的关键 ,大小台阶的扩孔次序和压下量是控制尺寸精度的重要因素。介绍了锻造大型台阶环的改进工艺 ,用该工艺进行生产不仅节省了原材料 ,而且提高了锻件的内部质量     

基于Dynaform的高强钢板冲压回弹补偿分析

对高强钢的冲压回弹及回弹补偿原理进行了分析。以某乘用车B柱高强钢加强板零件冲压加工工艺为例,在模具设计阶段对整个工艺过程进行CAE分析,在工艺参数优化前提下,对回弹进行全序计算和预测,并对模具进行回弹补偿。为高强钢冲压模具设计及工艺参数优化提供依据,从而降低模具开发风险,减少试模时间,缩短开发周期,提高产品质量,降低生产成本。模拟结果与实验较吻合,表明所采用回弹补偿方法是可靠的。     

采用CBN砂轮磨削气缸体Ni-SiC复合镀层

与离子溅射、火焰溅射、CVD等方法相比较, 采用电沉积方法形成的复合镀层有着非常优越的性能,但同时复合镀层的精密加工亦成为制约其性能发挥的关键.某小型航空发动机气缸体中由于有Ni-SiC复合镀层,其内孔磨削的难加工是制约该型号发动机性能的关键工艺.针对该缸体的特殊结构及镀层特点,文中采用合理的装夹方式及磨削工艺参数,在精密内圆磨床上采用陶瓷结合剂CBN砂轮实现了对Ni-SiC复合镀层内孔的磨削.实践证明,该工艺方法解决了Ni-SiC弥散复合镀层的精密加工难题,提高了加工效率,改善了表面尺寸形状精度和表面粗糙度.     

高低压联合转子材料及热处理工艺研究

根据高低压联合转子使用特性和技术要求 ,设计了相应的 2 .5 % Cr Ni Mo V钢转子材料 ,并进行了相关的物理和工艺参数试验 ,对试验结果进行了对比和讨论 ,认为该材料适用于生产高低压联合转子     

HEAT ENERGY DISSIPATION IN FATIGUE DAMAGE PROCESS

Using the dissipated energy as an essential parameter,the energy dissipative structure in pro-cess of fatigue damage of materials has been established.Through thermodynamic analysis forirreversible energy dissipation in fatigue damage process,the heat dissipative variations incyclic loading process as well as in a cycle have been systematically studied on the basis of lowcycle fatigue tests and infrared measurement of self-heating thermography.Meanwhile,thecyclic hysteresis energy and efficient energy dissipation (stored energy) have been proposedduring fatigue damage process.     

电弧炉主要工艺参数对单渣法炼钢的影响

单渣法炼钢工艺的设计思想主要体现在 :快速熔炼、减少吸气、熔氧结合、早期精炼。为较好地实施该工艺 ,电弧炉主要工艺参数及辅助条件应与之相适应。本文就此阐述了确定电弧炉设计和运行的最佳工艺参数的观点和方法 ,并讨论了其它辅助条件的相关内容     

异种金属摩擦焊接工艺参数优化算法

针对当前摩擦焊接工艺参数获取存在盲目性,提出在获得摩擦焊接工艺参数的预测范围基础上,结合正交试验进行分组.用一维有限差分的方法来对每组试验进行验证,对获得优异的工艺参数给出一维温度场,其结果与现有文献基本相符,从而证明了本算法的可行性.文中所提出的异种金属摩擦焊接工艺参数优化算法,对于实际生产中摩擦焊接工艺参数的制定,...