基于响应曲面法的高速铣削Ti6Al4V表面粗糙度的预测模型与优化

提出了一种铣削难加工材料钛合金Ti6Al4V表面粗糙度的建模方法。采用BBD响应曲面法,建立了用于表面粗糙度预测的多元回归模型,运用方差分析检验了该预测模型的拟合度,利用响应曲面法对表面粗糙度建立等值响应曲面,从而可以通过切削参数的优化在保证加工质量的前提下获得更高的材料去除率,实现难加工材料钛合金高效切削。     

球头阴极电解铣磨加工TC4钛合金试验研究

采用直径6 mm的球头阴极,通过内喷液式的供液方式,对TC4钛合金进行电解铣磨加工粗精加工试验研究.结果表明:采用球头阴极可以实现底面为曲面的沟槽加工,电解铣磨加工方法可以对沟槽进行连续的粗精加工,实现TC4钛合金曲面沟槽的高效精密加工.     

基于曲面再设计的钛合金高速铣削热研究

钛合金复杂曲面零件在航空航天、汽车及船舶等工业领域应用广泛。该类复杂曲面零件在高速铣削加工过程中由于加工轨迹曲线几何特征的变化,导致瞬时切削量不断变化,致使复杂曲面铣削热剧烈波动,影响零件表面完整性。为此,以钛合金TC4正弦轮廓曲面三轴高速铣削加工为例,以提高零件表面完整性为目标,通过微调加工余量实现半精加工工序曲面轮廓的再设计,确保加工过程瞬时切削面积恒定,使得TC4正弦轮廓曲面高速铣削过程铣削温度稳定,为实现高质量加工提供技术支撑。     

如何实现钛合金管件相贯线端口的机械加工

钛合金管件相贯线端口为不规则的曲面结构,且钛合金材料机械加工的特殊性,本文通过对钛合金材料的机械性能分析,配合适合管件的装夹方法,利用Master CAM编程软件实现3D模型编程,确定好机械加工工艺参数,实现钛合金管件相贯线端口的机械加工。     

基于国产装备的钛合金TC4高效铣削试验研究

钛合金TC4在航空领域得到广泛应用,然而其加工效率极低。以民机零件为试验对象,开展了钛合金高效铣削试验,试验结果表明:乳化液更利于切削热量的排放,减少刀具磨损,延长刀具寿命;利用3轴和5轴配合加工方式,可以提高航空工件曲面的加工效率,曲面重构可以提高工件的加工表面质量;合理的切削参数,能够充分发挥国产装备的切削性能,材料去除率达到了75 cm3/min。     

基于Kriging插值和遗传算法钛合金车削加工参数优化

钛合金较差的切削加工性不利于保证好的表面完整性,影响钛合金零件的使用性能。基于田口方法建立钛合金车削试验模型,考察切削用量对表面粗糙度、刀具寿命、切削力和材料去除率的影响规律,以材料去除率为目标函数,以表面粗糙度、刀具寿命和切削力为约束函数,基于Krig-ing插值的响应曲面法和遗传算法构建了钛合金车削参数优化模型。研究结果表明:钛合金车削过程参数最优的水平组合为v3f1ap1r1E3,优化结果与初始试验相比,表面粗糙度、刀具寿命、切削力和材料去除率分别改善了75.86%、65.16%、36.41%和557.91%。     

典型钛合金曲面壁板的高效加工

针对控制钛合金曲面壁板变形及提高零件表面粗糙度的问题,从定位方法、刀具选择、工位安排、余量设置以及编程要点等方面入手展开了工艺方法的研究,有效解决了一系列的加工难题。     

昆明机床 走极限加工之路

各项精度均达到亚纳米,配AC头可进行五轴联动的复杂曲面加工,能切削铝钛合金等多种特殊材料,在CCM T2012第七届中国数控机床展会上,沈机集团昆明机床股份有限公司推出一款可用于极限加工的超精密加     

提高钛合金蒙皮外形准确度的方法研究

本次研究是以数字化制造为基础,通过在热成型模上增加一套定位压点结构,利用高温下钛合金强度降低,而压点销强度相对较大这一特点,使钛合金板材在热成形的过程中同时标记出多个定位点,此定位点可以达到与零件曲面外形极高的一致性和连续性;然后通过钻模等辅助工装,将定位点钻制成定位孔;再借助激光切割等高精度切割设备,以定位孔作为定位基准,准确加工出零件外形。通过这种方法以实现钛合金蒙皮零件的精确制造,满足飞机无余量装配的要求。     

基于ABAQUS的微织构刀具切削机理研究

微织构刀具在切削过程中有减小切削力的作用,为了进一步研究微织构尺寸参数(包括宽度、间距、深度)的变化对切削力的影响,运用ABAQUS建立了微织构刀具切削钛合金的有限元模型,并进行中心复合试验得出响应曲面。响应曲面不仅可以直观地看出各变量对响应目标的影响,还可以研究几种因素间的交互作用,试验得出沟槽型微织构的间距对主切削力的影响最为显著,沟槽深度次之,宽度对主切削力的影响最小。     

控轧控冷工艺条件下X70针状铁素体管线钢铌、钛的析出行为

通过透射电镜研究了X70针状铁素体管线钢中微合金元素铌、钛在控轧和控冷过程中的析出行为。结果表明：析出粒子主要以两种形式存在,一种是在高温下尺寸较大的铌、钛复合粒子的析出,方形的TiN粒子先析出,随后含铌的粒子将包覆在TiN外面并以其为核析出,而不是独立形核;另一种是在低温条件下,由于变形使大量细小的近似球形的NbC在晶内的位错和亚晶上析出。同时还讨论了控轧控冷技术对第二相粒子析出的促进作用。     

氢对Ti600合金切削加工性能影响的试验研究

通过对不同氢含量Ti600合金试件进行车削试验,测量切削力和加工后表面粗糙度并观察切屑形貌,研究了氢对Ti600合金切削加工性的影响。试验结果表明:随氢含量增加,Ti600合金的切削加工性提高,并且有一个最佳氢含量范围;超过该氢含量范围,随氢含量增加,Ti600合金切削加工性变差。     

微量钛、硼对AM50镁合金组织和性能的影响

对在AM50镁合金中添加不同微量钛、硼元素后的微观组织和力学性能的变化规律进行了研究。结果表明：微量钛、硼的加入能够细化AM50合金的晶粒,改善第二相的形貌,使第二相变得细小,分布更加均匀;微量钛、硼在含量分别为0．002%和0．0010%附近时合金室温力学性能明显提高;过多添加钛、硼并不能明显提高AM50合金的力学性能。     

曲面铝合金锤击平整技术研究

以曲面铝合金为例,利用工业机器人锤击的方式对曲面类零件表面进行平整,并探究各锤击工艺参数对其表面的粗糙度、硬度及表面形貌的影响.将锤击装置装夹到工业机器人上,控制工业机器人以矩形光栅式运动路径对曲面铝合金表面进行锤击加工,并对锤击后表面的粗糙度、硬度及表面形貌进行测量观察.结果表明:经锤击加工后的铝合金表面粗糙度可达0...     

不锈钢外板对5A06铝合金板材液压胀形行为的影响

薄壁曲面铝合金零件整体液压成形时,易发生起皱和破裂缺陷,探讨通过施加外层板能抑制缺陷发生的机理。采用5A06铝合金内层板材和1Cr18Ni9Ti不锈钢外层板材,对双层板液压胀形行为进行研究。通过塑性理论分析板材液压胀形屈服半径,讨论经向摩擦力及法向压力对板材应力大小的影响;利用数值模拟给出内层板的应力、应变分布;通过双层板液压胀形试验,对比单层板和双层板条件下,铝合金内层板极限胀形高度、极限应变,分析双层板的变形协调性。结果表明:通过施加不锈钢外层板,减小了5A06铝合金内层板顶部位置面内的双向拉应力,减小了内层板变形区应力、应变梯度,使胀形变形更加均匀,胀形高度提高32%,顶部极限应变提高51.7%,极限应变显著提高。     

Nd:YAG laser alloying of high-speed steel tools with BN and Ti/BN and the effects on turning performance

A 400 W pulsed Nd:YAG laser was used to surface alloy BN and Ti/BN on AISI M2 steel using hexagonal BN powder and Ti foil (25 μm thickness). The clearance (flank) faces of the single-point tool were laser alloyed using BN and Ti/BN. Optical metallography, scanning electron microscope, Vicker's microhardness and X-ray diffraction were employed to characterize the alloyed layers. The depths of the laser-alloyed zones of BN- and Ti/BN-alloyed tools were about 140 μm and 260 μm respectively. The hardness of the laser-alloyed layer with BN was about 640 HV while that of the alloyed layer with Ti/BN was about 680 HV. The alloyed layers were free from cracks and porosity. Both the alloyed and unalloyed tools were then tested on a 14.7 kW engine lathe to turn AISI 1045 steel workpieces. The results indicated that the tool life of BN-alloyed tools was about 200% higher than that of the unalloyed tools, while the tool life of Ti/BN-alloyed tools was about 260% higher when the tool life criterion was chosen as 0.3 mm flank wear. Also, the tool wear rate was reduced by about 30% and 50% for BN-and Ti/BN-alloyed tools, respectively. The reduction in tool wear of the alloyed tools was attributed to a reduction of the chip-tool contact length (and consequently the reduction of coefficient of friction between the tool and workpiece material) and to the different chip formation mechanisms.     

Solid particle erosion behaviour of Ti6Al4V alloy

Abstract

The effects of particle impingement angle, impingement velocity and erodent particle size on the erosion rate and surface morphology of the Ti6Al4V alloy have been investigated comprehensively in order to evaluate solid particle erosion behaviour of Ti6Al4V alloy. Samples were eroded in a specially designed sandblasting system under various parameters using alumina (Al₂O₃) erodent particles. Surface morphology investigations were examined by scanning electron microscope using various analysis and modes (energy dispersive X-ray analysis, elemental mapping and compositional contrast). Ti6Al4V alloy showed ductile behaviour with a maximum erosion rate at 30° impingement angle. Erosion rate of Ti6Al4V alloy increased with increases in velocity and decreased with increases in erodent particle size. Scanning electron microscopy investigations of eroded surfaces of Ti6Al4V alloy samples reveal the dominant erosion mechanism such as microploughing, microcutting and plastic deformation. Embedded erodent particles on the surfaces of Ti6Al4V alloy nearly at all particle impingement angles and velocities were clearly detected.     

Multi-pass scratch test behavior of modified layer formed during plasma nitriding

316L stainless steel and Ti6Al4V alloy were plasma nitrided at different treatment parameters, and the wear behaviors of the modified layers formed on the surface during nitriding were investigated by multi-pass scratch test. Phase structure and cross-sections of modified layers were also examined with XRD and SEM. While a single modified layer formed on surface of the 316L stainless steel, both modified and diffusion layers were observed on the surface of the Ti6Al4V alloy after nitriding. As a result, it was observed that phase structure and thickness for modified layers of 316L stainless steel and Ti6Al4V alloy, respectively, were the significant parameters for friction coefficient and wear rate. In addition, diffusion layer formed during the nitriding process caused on increase of wear resistance of Ti6Al4V alloy by supporting the modified layer on the surface.     

曲线孔仿生电火花加工工艺规律的研究

曲线孔仿生电火花加工工艺是作者综合运用形状记忆合金功能材料、仿生技术和电火花等技术等研制开发出一种加工技术,该加工技术可方便地加工出形状复杂的曲线孔。本文对该加工技术的加工苣规律进行了实验研究,给出了加工极性、加工深度等对加工工艺效果的影响规律关系。     

新型Ti5553合金切削加工性

新型Ti5553合金是一种很难加工的钛合金.分析了Ti5553合金的切削加工性,提出了切削刀具、切削参数和装夹方式的选择,可以为从事Ti5553合金工件加工人员提供一定的帮助.