单晶锗微切削温度场建模及实验分析

针对单晶锗微切削热传导问题,采用移动热源法分别建立了在剪切滑移面热源和前刀面摩擦热源作用下单晶锗的微切削温升理论模型,计算了单晶锗三种切削速度下的最高切削温度,同时以同类硬脆性材料单晶硅的切削温度对此模型进行了验证。通过单点金刚石车削实验,利用红外热像仪对单晶锗微切削过程中的温度进行了在线测量。实验测量结果与模型计算结果对比发现,不同切削速度下,单晶锗的最高切削温度变化趋势一致,切削速度越大温度越高,其相对误差在2.56%～6.64%之间;单晶硅的最高切削温度相对误差为3.84%。模型能够对单晶锗及同类硬脆性材料的温度场进行较准确的预测,为研究其热效应提供进一步理论支持。      

新型陶瓷刀具

设在瑞典的桑德维克公司推出一种先进的陶瓷切削刀具。这种陶瓷刀具是以特殊组份的氮化硅为基体,且具有韧性和高耐磨性的切削表面。 与常规的碳化物陶瓷相比,该刀具的主要优点是具有高的切削速度(达800m/min)。氮化硅体材     

热压工艺参数对纳米SiC—Al2O3／TiC新型陶瓷刀具材料力学性？…

研究了压力、热压温度和保温时间等工艺因素对纳米ＳｉＣ－Ａｌ２Ｏ３／ＴｉＣ系新型陶瓷刀具材料的抗弯强度、韧性和硬度的影响。结果表明,对于纳米ＳｉＣ－Ａｌ２Ｏ３／ＴｉＣ系陶瓷复合材料,在压力为３０ＭＰａ热压温度为１７００℃,保温时间为６０ｍｉｎ时,材料的性能最好。     

硫对Y40CrCaS易切削刚性能的影响

为了研究１８ｔ电弧炉冶炼Ｙ４０ＣｒＣａＳ易切削钢的工艺参数及冶金效果，对１００ｋｇ感应炉采用喷射冶金方法，研究其工艺效果。实验证明，在保证钢中钙含量为０．００５％￣０．００７％的前提下，硫含量为０．１６５％，切削速度为２００，／ｍｉｎ，切削温度为８８０℃时，在刀具后刀面上形成了一层保护膜，使刀具寿命比切削Ｙ４０ＣｒＣａ钢时高１５倍。保护膜成分为３６．７８％Ａｌ２Ｏ３，３９．９８％ＳｉＯ２，１６．４     

碳氮化钛基金属陶瓷

金属陶瓷是等轴细晶硬质相埋置在金属或者合金粘结剂基体内的结构材料，因其具有优异的性能，Ｔｉ（Ｃ，Ｎ）基金属陶瓷正在取代切削刀具用的ＴｉＣ基陶瓷。在传统的碳氮化钛基金属陶瓷中，钼是润湿性和烧结性必不可少的配料。随着陶瓷硬质相预烧结固溶处理技术的创立，这种材料的发展进入了一个新阶段；在这里，钼就更是不可缺少的了。     

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%。     

新型陶瓷刀具材料抗弯强度的统计特性分析

研究了一种新型陶瓷刀具材料的抗弯强度有其统计特性，并据此优化了热压工艺参数，分析了其断裂特征。线性回归分析和Ｋ－Ｓ分布拟合检验的结果表明：该陶瓷刀具材料的抗弯强度很好地服从三参数威布尔分布，并进一步建立了抗弯强度尺寸效应的统计模型。     

Al2O3+TiC混合陶瓷刀具加工高铬铸铁辊的实践

介绍了高铬铸铁主要性能，特点和加工难度，对比分析了Al2O3 TiC混合陶瓷刀具材料成分，温度，硬度和耐用度的关系；优化选择了该刀具加工高铬铸铁的切削参数。     

超细晶硬质合金刀具Co含量对其耐磨损性的影响

用不同Co含量的超细晶硬质合金刀具对高温合金GH2132进行了高速连续切削试验,根据最小二乘法对试验结果进行了线性回归,建立了刀具寿命与切削速度之间的关系即T-υc经验公式;随后进行了高速断续切削刀具磨损试验,用连续变倍体视显微镜及显微摄影系统观察了刀具刃口和后刀面的磨损形貌,并对达到磨钝标准时的刀具后刀面磨损微区成分进行了电子探针能谱分析,探讨了粘结相Co含量对刀具磨损性能的影响机理。结果表明:粘结相Co含量过高或过低,均会降低刀具的耐磨损和破损性能。     

新型刀具材料与切削工艺的变革策略探讨

切削技术在长期发展中主要追求较高的加工质量、较短的切削时间、稳定的加工过程,近年来我国刀具材料、刀具应用性能逐步优化,全新的刀具材料开始出现应用,制造刀具的材料必须具有很高的高温硬度和耐磨性,必要的抗弯强度、冲击韧性和化学惰性,良好的工艺性(切削加工、锻造和热处理等),并不易变形。新型刀具材料大致分如下几类:高速钢、硬质合金、金属陶瓷、陶瓷、聚晶立方氮化硼以及聚晶金刚石。新材料促使传统切削技术开始全面变化,从生产实践中能得出,新材料制作而成的刀具,能全面提升加工切削速度以及进给速度,有效提升综合生产效率、加工精度。     

Rare earth ceramic cutting tool and its cutting behavior when machining hardened steel and cast iron

The addition of rare earth element yttrium played an important role in the improvement of both mechanical properties and wear resistance of Al2O3/(W,Ti)C ceramic cutting tool material.Mechanical properties especially the fracture toughness and flexural strength were obviously increased when a suitable amount of the yttrium were added.Wear resistance of the developed rare earth ceramic cutting tool material was higher than that of the corresponding materials without rare earth in the machining of the hardened 45# carbon steel and cast iron HT20-40.Wear modes of the Al2O3/(W,Ti)C rare earth ceramic tool materials were mainly flank wear and crater wear accompanied with slight notch wear when machining the hardened carbon steel.Wear mechanisms were major abrasive wear at low cutting speed and adhesive wear at high cutting speed.Wear modes were nearly the same except that the adhesion phenomenon in the crater area was intensified when machining cast iron.The flank wear area was relatively smooth with no obvious plowing phenomenon which was possibly concerned with the workpiece of low hardness and the adhesion phenomenon at high cutting temperature.     

1215MS易切削钢盘条翘皮成因

针对连续4批1215MS盘条均存在翘皮缺陷的现象,首先调查了该4批盘条对应浇次连铸坯投轧盘条情况,排除了整个浇次钢坯均存在质量问题的可能。接着对化学元素、皮下气泡、炼钢工艺和轧制工艺等翘皮影响因素进行了排查,筛选出产生本次翘皮的重点嫌疑因素：轧制温度、钢坯表面质量、夹杂物。然后通过生产试验和实验室研究,确定了产生翘皮的主要因素,最后通过生产实践进行了验证。结果表明,本次1215MS易切削钢盘条翘皮与轧制温度、钢的洁净度相关,与钢坯针孔、振痕无明显相关性。适当提高轧制温度可避免产生盘条翘皮。     

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。     

金属陶瓷复合塑料切粒刀的研制及应用

研究了ＴｉＣ－ＮｉＣｒ金属陶瓷在塑料切粒刀上的应用。这种切粒刀结构特点是金属陶瓷刀刃与钢刀体通过高温真空扩散焊复合为一体。结果表明这种金属陶瓷复合切粒刀性能比钢结硬质合金切粒刀更好。     

PCBN刀具在切削含硼高速钢轧辊中的应用

分析含硼高速钢轧辊的加工性能,选用PCBN刀具作为切削刀具,通过加工过程的分析得出合理的切削参数。     

Alternatives to Lead as a Machinability Enhancer in Free Cutting Steels

Low levels of lead are added to free cutting steels to improve machinability. For environmental reasons, there is interest in alternatives to lead that are technically and commercially viable. The machining performance of eight low carbon free cutting steels with alternative machinability enhancers, including additions of bismuth, increased sulphur (with and without tellurium), tin and phosphorus, has been investigated. In tests with high speed steel tools and lubricant, the leaded steel showed the best performance in terms of production rate, surface finish and chip form. In tests with coated carbide tools at a range of cutting speeds the standard non‐leaded 11 SMn30 steel performed well in terms of tool wear, but showed poorer chip form than the leaded steel. The steels with increased sulphur showed improved performance compared with the 11SMn30 steel in tests using high speed steel tools and lubricant, but did not approach the leaded steel in terms of production rate. The steels containing tin did not generally perform better than the 11 SMn30 steel. The 11 SMn30Bi steel gave performance approaching that of the leaded steel in tests with high speed steel tools and lubricant. However, the cost of this addition may make it uneconomic for large scale use.     

硫系易切削钢的研发

通过对硫系易切削钢的冶炼工艺及轧制工艺进行研究,总结了硫系易切削钢生产时的冶炼工艺及轧制工艺控制要点．成功地开发了硫系易切削钢并形成批量生产。     

New Grades of Hardmetals for a Rock Cutting Tools

A concept is developed for creating hardmetals for rock cutting tools. The concept pays particular attention to increasing energy absorption and the fatigue strength of hardmetals. In order to provide high rock cutting tool efficiency it should be fitted with hardmetal inserts which exhibit high bending strength, fracture toughness, total work of deformation, and energy absorption coefficient. This has been realized in the development of new grades of hardmetals for rock cutting tools. The efficiency of rock cutting tools fitted with inserts made from the new grades of hardmetal exceeds that of similar tools fitted with standard hardmetals inserts by a factor of 2.8     

宝钢厚板高敏感性裂纹钢切割裂纹机理研究

针对高裂纹敏感性钢,以耐磨钢为例,研究了耐磨钢板的显微组织,带温和非带温切割条件下硬度的变化,确定了火切端部裂纹形成与扩展机制。结果表明,带温切割条件下火切热影响区硬度梯度变化明显变缓,产生裂纹等缺陷风险大幅降低。对实际生产具有十分重要的实际应用意义。     

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.