硬质合金刀具铣削参数对激光熔覆TC4合金切削力的影响

为了提高激光熔覆TC4合金切削加工性能，通过设计高速铣削测试方案比较了TC4合金在铸造与激光熔覆条件下的切削性能差异。研究结果表明：激光熔覆钛合金在采用铣削加工过时表现出各向异性，铣削方向与熔覆轨迹一致，主切削力高于90°方向。在采用铣削方式处理钛合金时，主切削力随着单齿进给量不断增大而持续增大，主切削力随着切削刃不断增大而升高。主切削力在铣削深度增大的条件下呈线性上升，导致切削刃的切削抗力升高。铣削速度在100～400 m/min范围内，削主切削力在铣削速度逐渐增大的情况下呈现上升趋势。     

整体硬质合金立铣刀高速加工钛合金振动分析

针对切削振动制约钛合金高速加工的问题,采用变齿距结构铣刀,在干切削条件下对TC4钛合金进行高速铣削加工,建立动态铣削力模型,利用MATLAB软件对其进行快速傅里叶变换(fast Fourier transform,FFT),得到动态铣削力的频谱图;基于该图分析切削速度对切削稳定性的影响,得到颤振发生的切削速度。试验结果表明颤振会急剧地增加切削力幅值,大大降低已加工表面质量;根据频谱分析,在保证其它切削参数不变的条件下,最佳切削速度为160 m/min时,从而在保证刀具寿命和加工表面质量的前提下提高切削效率。     

Ti-5553合金车削加工性能研究

Ti-5553(Ti-5Al-5V-5Mo-3Cr-0.5Fe)合金具有优异的综合力学性能,正逐步替代TC4(Ti-6Al-4V)钛合金成为高强度航空用工件的制备材料。然而,由于Ti-5553合金机械加工效率低,一定程度上制约了其在航空领域的大规模应用。为此,对Ti-5553合金与TC4钛合金的车削加工性能参数进行了探索,发现在相同的切削速度下,Ti-5553合金的主切削力和吃刀抗力均高于TC4钛合金,且最高切削速度仅为50 m/min。此外,两种合金在切削过程中均会与车刀发生扩散反应,而Ti-5553合金对刀具的磨损更为严重。相信本研究将为后期优化Ti-5553合金的车削加工参数、提高其加工效率提供有利的实验数据支持。     

基于DEFORM-3D的EHM切削Inconel 718的刀具磨损研究

具有难切削加工问题的高温合金是发动机的关键材料,为了减少切削加工区域的刀具磨损深度,运用仿真软件DEFO-RM-3D建立了高温合金Inconel 718的EHM仿真模型,随后用EHM仿真模型分别进行了单因素实验与正交实验的仿真实验。实验结果表明:随着切削速度、切削深度、进给量三个切削因素的持续增大,刀具磨损深度表现为不断上升的趋势,而工件初始温度的不断升高则会持续降低刀具磨损深度;在工件初始温度不断升高的条件下,EHM仿真模型的刀具磨损深度比无电流加热切削刀具磨损深度降低了21.9%。     

快速落刀试验及有限元仿真分析Ti-6Al-4V合金锯齿状切屑特性

形成锯齿状切屑是钛合金加工的主要特征之一,也是进行钛合金切削机理研究的关键。首先设计并进行快速落刀试验,分析不同切削速度下锯齿状切屑的形成特点与变化规律;为获得锯齿状切屑内部的物理力学性能参数,对Ti-6Al-4V钛合金切削加工进行有限元仿真分析,揭示锯齿状切屑的形成对切削力的影响及切屑形成时剪切区与材料堆积区的温度变化规律,为揭示钛合金加工的内在本质及实现钛合金高速高效加工提供支持。     

AF1410超高强度钢硬质合金加工刀具的磨损机理

AF1410超高强度钢是具有难加工特性的新型结构材料,通过设计正交实验,研究涂层硬质合金刀具切削AF1410超高强度钢的切削力和刀具寿命,分析达到磨钝标准的硬质合金刀具前、后刃面的磨损形貌,以及刀具磨损机理。结果表明,刀具寿命随铣削深度和铣削速度增大而线性减小,随着每齿进给量和铣削宽度增加,刀具寿命下降趋势逐渐放缓甚至略有增加。刀具磨损分为3个阶段:磨合阶段—稳定磨损期—快速磨损阶段,在快速磨损阶段刀具磨损迅速增加,直到刀具失效。前、后刃面均发生刀具材料的严重剥离,同时粘结大量AF1410钢屑。刀具涂层失效的主要机理为磨粒磨损,刀具基体主要失效机理为扩散磨损和粘结磨损。     

钛二维机加工的切削力预测

<正>对材料进行切削加工时,除要考虑被切削材料和刀具这两个重要因素,也要考虑夹具、切削参数和冷却液等其他因素。在切削加工过程中,被切削材料上不需要的部分在刀具边缘变成切屑,切屑形成区的压应力和摩擦力会对切削力产生影响。金属切削是一种塑性变形过程。为观察和预测钛及钛合金切削过程中的切削力,开发了DEFORM2D软件来模拟切削过程。该软件使用有限元方法模     

钛合金冷切削加工实践研究

钛合金属于机械加工行业典型的难加工材料之一，为有效提高钛合金的冷切削加工性能，对钛合金冷切削加工进行长期的实践加工探索。分析钛合金冷切削加工方式车削、磨削、钻削、铰削和攻丝的加工过程，总结给出各种冷切削加工方式的刀具材料、刀具参数和切削用量的具体推荐数值。钛合金冷切削加工参数推荐值，可为钛合金材料的实际冷切削加工应用提供有用借鉴和必要的参考。     

PCBN刀具高速精密切削W-Ni-Fe合金的性能研究

采用PCBN刀具对W-Ni-Fe合金进行高速精密切削试验,通过观测PCBN刀具前、后刀面的磨损形貌,分析了刀具的失效磨损机理;从CBN含量、刀具参数以及已加工表面粗糙度方面研究了PCBN刀具加工W-Ni-Fe合金的切削性能。结果表明,CBN含量高且刀尖圆弧半径大的PCBN刀具具有更长的使用寿命,在高速、低进给、小切深条件下可获得良好的表面质量。SEM和EDS分析结果表明,PCBN刀具高速精密切削W-Ni-Fe合金的磨损机理为粘结磨损、扩散磨损、局部剥落、氧化磨损以及崩刃磨损等多重磨损机理共同作用的结果。     

含硫齿轮钢20CrMnTiH中硫化物对切削性能的影响

在不同切削速度(200～230 m/min)和切削深度(0.5～2 mm)下试验研究了普通20CrMnTiH齿轮钢(0.006%S)和含硫20CrMnTiH齿轮钢(0.031%S)的切削性能。结果表明,随切削速度增大,刀具的磨损增大,在200 m/min,0.031%S钢是0.006%S钢刀具的使用寿命的2.8倍;在230 m/min,0.031%S钢是0.006%S钢刀具使用寿命的2.6倍;随切削深度增加,切削力增加,但在相同切削深度下,0.031%S钢的切削力低于普通0.006%S钢;由于0.031%S钢存在≤6μm的MnS夹杂,使切屑易断,并硫化物夹杂能够包裹Al₂O₃尖晶石夹杂,减少刀具磨损,提高钢材的切削性能。     

浅谈加工模具中刀具材料的选用

分析了焊接切削用刀具在切削性能和加工精度方面的不足,比较了新型模具材料的优缺点,认为氮化硅系陶瓷刀具和碳化钛基硬质合金刀具。适合加工小型模具,而大型模具使用涂层硬质合金刀具较为合适。     

低碳高硫易切削钢的切削性能研究

 对宣钢生产的X1215低碳高硫易切削钢进行了切削试验,运用扫描电镜研究了钢中的夹杂物形态。切削试验表明,该钢的易切削性能优于45钢,切削比Kr达到1.48。分析表明,该钢中全氧的质量分数为120×10-6 时,钢中大量存在的条形硫化锰及纺锤形硫化锰-氧化物的复合夹杂是钢材切削性能优良的主要原因。     

Wear resistance in ceramic silicon nitride cutting tools bearing continuous or discrete titanium nitride coatings

Measurements have been made on the wear resistance of ceramic cutters based on silicon nitride and bearing titanium nitride coating during the continuous machining of ShKh15 steel. The coatings were deposited by cathode sputtering. Use was made of continuous coatings and discrete ones in the form of ordered fragments. The continuous TiN coatings raise the wear resistance by a factor of 1.7, while the factor is 2.2 for the discrete TiN coatings. The performance of the tool is also improved in the case of the discrete coatings as the cutting speed and feed can be raised by comparison with tools with continuous coating.     

易切削齿轮钢22CrMoHS的开发

苏钢开发了一种新的易切削齿轮钢22CrMoHS （/%:0.19～0.25 C,0.80～1.00 Mn,≤0.025 P,0.040～0.060 S,1.00～1.40 Cr,0.35～0.45 Mo）,S控制在0.040%～0.060%;通过控制电弧炉终点[C]在0.05%～0.12%;LF精炼初期渣的碱度（R）和Al2O3含量分别为4～5和25%～35%,在精炼后期渣碱度（R）和Al₂O₃含量分别为3～4和25%～35%;VD后钙处理,使钢中[Ca]在0.0015%～0.0025%;连铸二冷比水量0.81 L/kg,控制拉速0.75～0.80 m/min等工艺,钢中硫化物形态主要为球形,球化率达95%以上,材料的切削性能得到明显改善。     

关于阴极炭块切削刀具问题的探讨

通过阴极炭块铣削刀具的硬度和耐磨性、强度和耐热性、切削力与几何角度等问题的分析探讨,寻找提高切削刀具耐用度的有效途径,满足阴极炭块使用技术要求。     

PCBN刀具及其高速切削性能研究进展

简要介绍了我国PCNB刀具发展现状及其切削性能,详细介绍了国内外PCBN刀具高速切削的研究进展,主要包括:PCBN刀具高速切削淬硬钢的研究,高速切削各种铸铁的研究,高速切削钛合金的研究,高速切削钨及其合金、喷涂材料的研究。分析了我国PCBN刀具发展存在的问题,并提出了相关建议。     

Al2O3/TiCN-0.2% Y2O3 Composite Prepared by HP and Its Cutting Performance

Al₂O₃/TiCN-0.2% Y₂O₃ composites were fabricated by hot pressing sintering. The effect on mechanical property and microstructure of the sample composition and HP temperate was investigated. The results of Al₂O₃/TiCN-0.2% Y₂O₃ were satisfied. The bending strength, fracture toughness, Vickers hardness was respectively 1015 MPa, 6.89 MPa·m^1/2 20.82 MPa at 1650 °C for 20 min. Good wear resistance was found for the kind of ceramic material when used as cutting tools in the machining of the hardened carbon steel. By the compared experiment for the cutting performances, it could be seen that the performance of this composite material was better than that of the ceramic tool material YT15 for continuously cutting quenched steel. This kind of composite tool material is suitable for continuously cutting quenched steel No.45, especially intermittently cutting quenched steel.     

数控加工大圆弧形面的切削方式比较与循环程序编写

分析比较了在CK010数控机床上加工大圆弧形面时的几种走刀路线,认为圆弧走刀法可有效提高生产效率,保证产品质量,并指出矢量法编程方式是大规模加工大圆弧形面的快捷方便的首选编程方式。     

Cutting directions of bone with biomaterials in situ does influence the outcome of histomorphometrical quantifications

Ten commercially pure titanium implants were inserted in the tibia of ten mature New Zealand white rabbits for a healing period of 3 months. Cut and ground sections were performed on transversely and longitudinally cut tibia bone with implants in situ. Each implant with surrounding bone was processed by (a) dividing it into two parts by cutting transversely through the tibia and then (b) cutting one of the implant halves longitudinally through the tibia. In both cases 10 microns sections were made. Computerized histomorphometrical calculations of the bone-to-metal contact and the bone area in the threads were performed and comparisons of the differently cut sections were made for the same implant. Larger amounts of bone-to-metal contact and bone area in the threads were observed in the longitudinally cut samples in comparison to transversely cut ones. A strong statistically significant difference was obtained when comparing the transversely with the longitudinally cut samples with respect to bony contacts in the cortical region, demonstrating 25% more bone-to-metal contact lengths in the longitudinal cutting direction of the tibia. Quantitative histomorphometrical comparisons should, therefore, be performed on samples that are cut in the same direction.