Comparison of the wear resistance of selected steels and cemented carbide cutting tool materials in machining wood

An experimental investigation is described where specimens of selected steels and cemented carbides are tested to simulate cutting green wood and cured wood. Extensive results are presented that show quantitatively the progressive wear of several Stellites, steels and cemented carbides as a function of time for sliding under wet and dry conditions.A simple theoretical analysis of tool wear that applies to cutting green wood with cemented carbide tools is described. The analysis, which indicates the important parameters in the wear process, is used to predict the effect of carbide particle size on wear rate. Comparisons are made between the predicted and experimentally determined wear rates for two groups of cemented carbide materials. Good agreement is found between experimental measurements and theoretical predictions. It is shown that wear depends on carbide particle size. Superior wear resistance of cemented carbides is attributed to the high hardness and low chemical reactivity of the carbide phase. The improved wear resistance of the Stellites is attributed to the low reactivity of the matrix.     

涂层硬质合金刀具磨损机理的研究

通过高速切削试验,观察了涂层刀片的磨损过程,描述了其磨损形态,分析了涂层刀片磨损率不同的原因,提出了涂层硬质合金刀具的磨损机理模型以及涂层硬质合金刀具的磨损类型。     

车削加工陶瓷材料时刀具磨损表面形态的研究

分别使用硬质合金刀具、金刚石刀具、立方氮化硼刀具对氟金云母陶瓷及二硅酸锂玻璃陶瓷材料进行车削试验。利用显微镜观察刀具磨损形貌,通过能谱分析研究了刀具的磨损机理。试验结果表明,刀具磨损部位主要集中在刀尖和后刀面,刀具磨损形式主要为磨料磨损和粘结磨损。用硬质合金刀具车削氟金云母陶瓷时,切削深度越小,磨料磨损越严重。     

Carbide tool wear mechanism in turning of Inconel 718 superalloy

Wear surfaces of the cutting tools are analyzed to study the wear mechanism of cemented carbide tools in turning in Inconel 718 superalloys. SEM and EPMA analyses indicated that the wear of carbide tools during high speed turning condition (V = 35 m min⁻¹) was caused by diffusion of elements (Ni or Fe) in workpiece into tool's binder (Co) by a grain boundary diffusion mechanism. This action weakened the bonding strength between carbide particles (WC, TiC, TaC) and the binder (Co). The carbide particles were then detached out of the cemented carbide tool by high flow stresses. The proposed grain boundary diffusion mechanism is also confirmed by theoretical analysis.     

Wear Mechanism of Cemented Carbide Tool in High Speed Milling of Stainless Steel

Adhesion of cutting tool and chip often occurs when machining stainless steels with cemented carbide tools. Wear mechanism of cemented carbide tool in high speed milling of stainless steel 0Cr13Ni4 Mo was studied in this work. Machining tests on high speed milling of 0Cr13Ni4 Mo with a cemented carbide tool are conducted. The cutting force and cutting temperature are measured. The wear pattern is recorded and analyzed by high?speed camera, scanning electron microscope(SEM) and energy dispersive X?ray spectroscopy(EDS). It is found that adhesive wear was the dominant wear pattern causing tool failure. The process and microcosmic mechanism of the tool's adhesive wear are analyzed and discussed based on the experimental results. It is shown that adhesive wear of the tool occurs due to the wear of coating, the a nity of elements Fe and Co, and the grinding of workpiece materials to the tool material. The process of adhesive wear includes both microcosmic elements di usion and macroscopic cyclic process of adhe?sion, tearing and fracture.     

[刀具及切削工艺]高速铣削中TaC（NbC）对硬质合金刀具磨损性能的影响

针对航空航天钛合金加工时硬质合金刀具磨损过快的难题,制备了主元素一致、微量合金碳化物TaC（NbC）含量不同的两种WC-Co基硬质合金材料。采用高温维氏硬度计检测两种材料的高温硬度和高温断裂韧性,并制备相同几何参数的立铣刀对钛合金TC4进行铣削加工试验。试验结果表明：在硬质合金中添加微量合金碳化物TaC（NbC）,可以同时提高材料的高温硬度和高温断裂韧性,在相同的切削条件下,添加微量合金碳化物TaC（NbC）的硬质合金立铣刀比未添加微量合金碳化物的立铣刀耐磨性更好,刃口断裂裂纹更少,刀具使用寿命更长,更适合航空航天钛合金材料的高速铣削加工。     

铁基粉末冶金材料的高速干切削试验研究

用陶瓷刀具、涂层刀具和硬质合金刀具进行了铁基粉末冶金零件的干切削对比试验,研究了切削速度、切削深度以及进给速度与刀具耐用度和加工表面粗糙度的关系,分析了陶瓷刀具的磨损机理。结果表明所选用陶瓷刀具的切削性能明显优于涂层刀具和硬质合金刀具;陶瓷刀具前刀面主要磨损形式为月牙洼磨损与剥落,后刀面的主要磨损原因为磨粒磨损;认为陶瓷刀具更适合用于粉末冶金零件的切削加工。     

Comparison of the wear resistance of various grades of cemented carbides that may find application in wood machining

A laboratory test is described in which specimens of rectangular cemented carbide tool inserts of a standard size are allowed to slide against a rapidly rotating fiberboard disc in either the presence or the absence of a mist spray of a dilute organic acid (tannic acid or acetic acid) to simulate the cutting of green wood and cured wood respectively. It is shown that the worn surfaces of cemented carbide tools used in (field) service are remarkably similar to the worn surfaces of specimens used in the laboratory (simulation) tests.Extensive results are presented that show quantitatively the progressive wear of a wide range of cemented carbides as a function of time for sliding under wet and dry conditions. It is shown that wear depends on the type and amount of binder present in the cemented carbide and on the nature of the environment. Materials with Co-Cr and Ni-Cr binders containing significant amounts of chromium showed the greatest resistance to wear.     

An Investigation of the Wear Mechanisms of Polycrystalline Cubic Boron Nitride (PCBN) Tools when End Milling Hardened Steels at Low/Medium Cutting Speeds

The commercial availability of PCBN tools has created the possibility for great improvements in the area of machining hardened steels. Roughing and finishing cuts can be carried out to achieve a surface finish as good as that obtained by grinding. Through this procedure, fabrication time can be greatly reduced and quality increased. This work presents a study of the wear of PCBN and cemented carbide tools when end milling hardened steels at low/medium cutting speeds. The experiments were carried out using a 12.0 mm diameter end milling tool with an indexable insert tipped with PCBN. Removal rate was 384 mm 3 min −1 . Carbide inserts were also tested under the same cutting conditions. The tests were carried out in the dry condition. Three different hardened steels were cut and the wear mechanism was investigated using a scanning electronic microscope (SEM). The minimal wear mechanism found was a combination of adhesion and abrasion. The wear occurred predominantly on the flank face, although some indications of crater wear were also detected. The amount of wear was significantly smaller for PCBN tools than for cemented carbide tools.     

A study of the cutting-induced heating effect on the machined surface in ultra-precision raster milling of 6061 Al alloy

Ti-6Al-4V alloy is an attractive material in many industries due to its unique and excellent combination of strength to weight ratio and their resistance to corrosion. However, because of its low thermal conductivity and high chemical reactivity, Ti-6Al-4V alloy is generally classified as a difficult-to-cut material that can be characterized by low productivity and rapid tool wear rate even at conventional cutting speeds. It is well known that tool wear has a strong relationship with the cutting forces and a sound knowledge about correlation between cutting forces variation and tool wear propagation is vital to monitor and optimize the automatic manufacturing process. In the present study, high-speed end-milling of Ti-6Al-4V alloy with uncoated cemented tungsten carbide tools under dry cutting conditions is experimentally investigated. The main objective of this work is to analyze the tool wear and the cutting forces variation during high-speed end-milling Ti-6Al-4V alloy. The experimental results show that the major tool wear mechanisms in high-speed end-milling Ti-6Al-4V alloy with uncoated cemented tungsten carbide tools are adhesion and diffusion at the crater wear along with adhesion and abrasion at the flank wear. The cutting force component in the negative y-direction is more dominant of the three components and displays significantly higher magnitudes than that of the other two components in x- and z-directions. The variation of cutting force component F _y has a positive correlation with the tool wear propagation, which can be used as a tool wear indicator during automatic manufacturing process.     

基于XPS硬质合金刀具氧化磨损的试验分析

采用多功能表面分析系统对车铣加工Ti6Al4V钛合金的硬质合金刀具进行X射线电子能谱分析(XPS)。通过对磨损区域进行全谱扫描和精细谱扫描,应用XPSPEAK4.1和Origin7.5对所得数据进行分峰拟合处理,最后分析了所生成的氧化物对刀具磨损和刀具寿命的影响。试验结果表明涂层材质为S30T的刀具磨损表面有Ti O_2、Al_2O_3、Co O和Ti N等物质生成;H13A非涂层材质刀具磨损表面有Ti O_2、WO3和Co_3O_4等氧化物生成。     

镍基粉末冶金零件的切削试验研究

对陶瓷刀具和硬质合金刀具进行了镍基粉末冶金零件的干切削对比试验,测量了切削力和加工表面粗糙度,分析了刀具的磨损机理。试验结果表明:陶瓷刀具的切削性能明显优于硬质合金,适合于粉末冶金零件的切削加工。     

高速干切削铁基粉末冶金零件时细晶粒硬质合金刀具的切削性能研究

用细晶粒硬质合金刀具进行了铁基粉末冶金零件的高速干切削试验。研究了切削参数与刀具耐用度以及加工表面粗糙度的关系,给出了刀具的主要磨损形态,通过能谱分析研究了刀具的磨损机理。结果表明:所选用细晶粒硬质合金刀具具有较高的刀具耐用度和较好的加工表面粗糙度,适合于铁基粉末冶金的加工;细晶粒硬质合金的主要磨损形态是前刀面的月牙洼磨损;主要磨损机理是扩散磨损、粘结磨损。     

Analytical techniques in fundamental tool wear research

As no systematic work evaluating the usefulness of the various analytical techniques available for fundamental tool wear research has been reported, an attempt has been made to evaluate the advantages and limitations of electron and ion beam instruments for quantitative analysis of the chemical and structural changes taking place in cemented carbide tools as a result of the metal cutting process.     

硬质合金切槽车刀性能分析

运用有限元方法对钛合金环槽车削过程进行数值模拟计算,得到硬质合金切槽车刀表面的温度,并应用Usui磨损理论计算刀具磨损速率。通过改变切削速度和进给量,获得不同工艺参数下刀具最高温度及刀具前刀面磨损速率。对环槽车削过程的热力耦合模拟结果进行分析,获得刀具切削过程中的温度及磨损速率的变化规律。结果表明,刀具温度和刀具前刀面磨损速率与工艺参数之间存在密切关系,合理选择工艺参数能有效提高硬质合金切槽车刀的性能。     

电磁耦合处理对硬质合金刀具切削力的影响研究

为了研究电磁耦合处理对硬质合金刀具切削力的影响,利用电磁耦合设备对YT15硬质合金刀具进行强化处理,通过干车削40Cr试验研究不同电磁耦合处理参数情况下对刀具切削力的影响。结果表明,在适当的电磁耦合处理参数作用下刀具的总切削力大幅下降。通过采集到能反映切削过程稳定性的总切削力信号幅值,发现电磁耦合处理可以提高切削稳定性、延缓刀具磨损。建立了相应的修正后的电磁耦合处理刀具的切削力经验公式,分析了各切削要素对处理前后硬质合金刀具切削力的影响。     

纯钒车削刀具磨损表面形态及机理研究

对金刚石刀具、涂层刀具及硬质合金刀具车削纯钒时刀具磨损形态及其磨损机理进行观察和分析.结果表明,在所选取条件下,不同刀具材料对工件材料切削时表现出的刀具磨损形态主要为前刀面磨损、后刀面磨损、微崩刃、剥落和粘结等.刀具的前刀面主要是沿切屑流出方向的沟槽形月牙洼磨损,而后刀面以粘结磨损为主.CD10刀具和H10非涂层刀具具有较佳的切削性能,而H13A非涂层刀具和GC1025涂层刀具不适于纯钒车削.     

基于 STFT 的织构涂层硬质合金表面振动解析方法

针对织构涂层复合工艺对硬质合金表面改性时存在消极振动的问题,提出一种基于织构涂层表面摩擦振动行为的解析 方法来探索织构涂层复合工艺改性效果。 因此,搭建了微织构 AlSiTiN 涂层硬质合金-钛合金磨盘摩擦磨损试验平台,基于短 时傅里叶变换(STFT)与灰度算法对摩擦振动变化规律性映射和振动行为平稳时段进行了获取,进而分析了微织构 AlSiTiN 涂 层工艺参数对硬质合金的改性效果。 试验研究得出了微织构及 AlSiTiN 涂层对硬质合金表面耐磨改性效果最为积极的时间 段,即自接触摩擦起第 5~ 25 min 的稳定作用时期,得出微织构及 AlSiTiN 涂层参数对硬质合金表面改性的影响机理,优选该复 合改性方法抑制硬质合金表面消极摩擦振动的工艺参数,为提升硬质合金表面性能研究提供新思路。     

ZrN涂层刀具的滑动磨损特性研究

山东大学摘要:采用电弧离子镀法在硬质合金刀具表面制备了厚度为2.19~5.23μm的ZrN系列涂层,测定了涂层的显微硬度,并通过划痕试验和摩擦磨损试验考察了涂层与基体的结合强度及其摩擦磨损性能。在扫描电镜下观察磨损表面形貌,结果表明:ZrN系列涂层能够显著提高硬质合金刀具的表面硬度;涂层与基体的结合强度较高,划痕临界载荷高于60N;与此同时,电弧离子镀法ZrN系列涂层可以显著改善硬质合金刀具的耐磨性能。磨损机理主要是磨粒磨损和涂层的微剥落。     

纳米硬质合金刀具切削Al/SiC_p复合材料的实验

针对SiC颗粒硬度高,切削Al/SiCp复合材料时刀具磨损剧烈,本文提出用具有较高硬度、韧性及良好抗磨损能力的WC-7Co制备纳米硬质合金刀具,并对Al/SiCp复合材料进行了切削实验。研究了纳米硬质合金刀具磨损机理和Al/SiCp复合材料的切屑去除机理,以及刀尖处后刀面磨损值。研究认为,纳米硬质合金刀具磨损的机理为SiC颗粒的微切削作用引起的磨料磨损,及SiC颗粒对刀尖刃口的高频、断续冲击引起的微崩刃及微破损;Al/SiCp复合材料的切削实质是断续切削;去除机理为切屑的崩碎去除;纳米硬质合金后刀面磨损值较普通硬质合金小30%～50%。实验表明,纳米硬质合金较普通硬质合金更适于加工Al/SiCp复合材料。