硬质合金刀具高速车削钛合金的切削性能研究

采用单因素试验法,用未涂层硬质合金刀具和TiAlN涂层硬质合金刀具对Ti-6Al-4V钛合金进行了高速干车削试验,通过对切削过程中切削力、刀具寿命、切削温度以及加工表面粗糙度的分析,得出了两种刀具高速干车削钛合金的切削性能,为钛合金高速切削刀具的设计提供了试验依据。     

不同材料和刀尖圆弧半径刀具加工TC4钛合金的表面质量及刀具磨损行为

采用聚晶立方氮化硼(PCBN)、TiAlN涂层硬质合金(2种刀尖圆弧半径)和Al_2O_3+TiC涂层硬质合金等3种刀具车削TC4钛合金工件,测试了刀具后刀面磨损宽度和工件表面粗糙度,观察了刀具的磨损形貌并分析了磨损机制;同时,研究了刀尖圆弧半径对工件表面粗糙度和切屑形貌的影响。结果表明:TiAlN涂层硬质合金刀具具有比其他2种刀具更长的使用寿命,且加工后工件的表面粗糙度最小、表面质量最好,其磨损形式主要为磨粒磨损和黏结磨损;PCBN刀具的失效形式主要为前刀面和后刀面崩塌,而Al_2O_3+TiC涂层硬质合金刀具的磨损形式主要为扩散磨损;刀尖圆弧半径的增大有利于提高TiAlN涂层硬质合金刀具的断屑能力以及加工工件的表面质量。     

金刚石涂层刀具铣削高硅铝合金的性能研究

选用未涂层、TiAlN涂层及金刚石涂层整体硬质合金两刃平头立铣刀,在相同切削参数下进行高硅铝合金的高速铣削加工试验。试验结果表明:金刚石涂层铣刀具有良好的耐磨性,在切削过程中刀刃磨损均匀缓慢,刀具使用寿命长,加工表面粗糙度值稳定性好,是铣削高硅铝合金的理想刀具。     

等离子体辅助激光织构化预处理增强TiAlN刀具涂层膜基结合强度的机理研究

物理气相沉积(PVD)TiAlN涂层刀具在难加工材料高性能切削中有巨大的应用需求,而涂层膜基结合强度成为制约其高性能切削难加工材料的关键问题。为解决该问题,采用纳秒激光和等离子体刻蚀系统对硬质合金基体表面进行预处理,而后进行TiAlN涂层,最终获得传统涂层刀具(CCT)、激光织构化涂层刀具(LCT)、等离子体刻蚀涂层刀具(CECT)、等离子体辅助激光织构化涂层刀具(LECT)。分析织构化基体晶相结构、比表面积、表面能等材料特性和表面状态,并利用上述制备的涂层刀具进行划痕试验和干切削316奥氏体不锈钢试验。结果表明,通过基体表面等离子体辅助激光织构化预处理,可改善涂层膜基化学键合性能的差异,增加基体表面比表面积和表面能,改善膜基间物理结合和化学键合界面,进而提升TiAlN涂层膜基结合强度。与其他三种涂层刀具进行划痕试验与切削试验对比,进一步验证了LECT的涂层膜基结合强度最好。     

钛合金TC11车削中已加工表面质量试验研究

为了研究车削钛合金TC11时切削速度和刀具磨损对已加工表面质量的影响,选用涂层硬质合金刀片CNMG120408在不同切削条件下进行车削试验,分析后刀面磨损量随切削时间的变化规律;对比磨损刀具与新刀具切削的工件表面,观察表面粗糙度、表面形貌、显微硬度以及表层微观组织情况,分析切削速度和刀具磨损对已加工表面质量的影响规律。试验结果表明:在刀具磨损初期,即新刀具切削时,切削速度从60m/min增加到100m/min,刀具磨损程度增大,表面粗糙度值降低,硬化层深度减小,加工硬化程度略微增大,表面塑性变形层深度减小;在刀具磨损终期,不同切削速度下的表面粗糙度增大,表面形貌变差,硬化层深度和加工硬化程度增加,表面变形程度增大,塑性变形层深度增加。     

润滑方式对高速铣削淬硬钢的影响

使用TiSiN和TiAlN涂层刀具在3种不同冷却润滑方式下,在高速加工中心上采用固定的切削工艺参数,对淬硬钢SKD11(HRC 62)进行切削试验,研究加工工件的表面粗糙度、切削力、刀具磨损及切屑形态的不同.结果 表明:TiSiN涂层铣刀相对于TiAlN涂层能更好地降低已加工面的表面粗糙度,减小切削力,降低刀具的磨损;在微量润滑(MQL)方式下,已加工面的表面粗糙度值低于干切削和冷风切削条件;在减小切削力、降低刀具磨损、改善切屑形态方面,冷风切削的效果优于干切削,MQL润滑方式增大了刀具切削力.     

氮硅涂层陶瓷刀具切削铸铁磨损机理研究

为研究氮硅涂层陶瓷刀具切削性能及磨损机理,采用物理气相沉积(PVD)工艺分别在氮化硅刀具表面沉积TiAlN和CrAlN涂层,利用切削灰铸铁HT200实验对刀具寿命和磨损机理进行了系统研究,探讨不同切削深度、进给率、切削速度下刀具的磨损情况.着重关注陶瓷涂层车削铸铁的最佳切削速度,分析了不同切削速度下刀具的切削性能.结果表明:TiAlN和CrAlN涂层刀具能有效提高刀具硬度,三种刀具切削灰铸铁的磨损机理无明显区别,磨损机制主要是磨粒磨损;随着切削速度的增大(Vc=250 m/min～450 m/min),氮化硅涂层陶瓷刀具的切削寿命均迅速减少,能够为氮化硅涂层陶瓷刀具的研发提供理论指导.     

硬质合金刀具车削Cr12Mn5Ni4Mo3Al不锈钢的试验研究

使用硬质合金刀具YW2进行Cr12Mn5Ni4Mo3Al不锈钢的干车削试验。分析了切削速度对车削力及表面粗糙度的影响,并采用扫描电子显微镜(SEM)观察刀具的磨损形貌。研究结果表明:使用硬质合金刀具YW2干车削Cr12Mn5Ni4Mo3Al不锈钢时,在小进给量和小背吃刀量切削的条件下,车削三向力的大小顺序为:径向力轴向力切向力;受积屑瘤的影响,表面粗糙度呈现出随车削速度的变化先减小后增大的变化趋势;硬质合金刀具后刀面磨损较轻微,而沿刀尖周围出现了较严重的粘结现象,前刀面上出现了较严重的划痕现象,低速时,前刀面还出现了贝壳状的剥落现象。     

基于HSM的氮铝钛涂层刀具切削性能的研究

通过对TiAlN涂层硬质合金刀具在淬硬模具钢高速数控切削中的切削力、刀具磨损及加工策略的分析,为模具材料的高速数控加工提供了实用依据。     

TiAlSiN涂层刀具的发展与应用

为满足更加复杂的工业应用需求,在现有刀具涂层中添加其他元素来改善涂层的力学性能,成为目前刀具涂层领域研究的热点。用多弧离子镀和磁控溅射等PVD方法,在TiAlN基中加入Si元素制备的TiAlSiN刀具涂层具有特殊的纳米结构,表现出了更加优异的力学性能、热稳定性和抗氧化性,适合于高速和干式切削,引起了极大的关注,具有广泛的应用前景。本文对TiAlSiN刀具涂层的组织结构、性能特点和制备方法,以及TiAlSiN涂层刀具的应用做了系统的介绍。     

Behavior of Coated Carbide Tools in High Speed Machining of a Nickel Base Alloy

Multilayer TiN/TiCN/TiN and single-layer TiAIN PVD coated carbide tools were used to machine a nickel base, C-263, alloy at high-speed conditions in order to investigate their performance in terms of tool life, surface finish and component forces generated during machining. The test results show that the triple layer, TiN/TiCN/TiN, coated inserts gave longer tool life when machining at higher speed and depth of cut conditions while the single layer, TiA/N, coated inserts produced better surface finish. The feed forces recorded were generally higher than the cutting forces. This could perhaps be attributed to the adverse effect of burr formation and work hardening of the workpiece associated with prolonged machining. Analysis of the test results indicate that the difference in thermal properties and tribo-chemical behaviour of both the coating and substrate materials are the major factors influencing the tribo-contact at the tool-chip interface during machining. Wear mechanisms of the coating materials can also affect tool performance in terms of tool life, surface finish and component forces.     

Effects of Coating Materials on the Machinability of a Nickel Base,C-263, Alloy

PVD coated (TiN/TiCN/TiN, TiAIN and TiZrN) and uncoated carbide tools were used to machine a nickel base, C-263, alloy at high-speed conditions. The test results show that the multiple TiN/TiCN/TiN coated inserts gave the best overall performance in terms of tool life when machining at cutting speeds up to 68 m min and at depths of cut of 0.635 mm, 1.25 mm and 2.54 mm. All the tool grades tested gave fairly uniform surface roughness (Ra) values, below the rejection criterion, at lower speed conditions. The TiZrN coated inserts gave the lowest component forces when machining at lower cutting speed conditions while the TiA/N coated inserts gave the lowest component forces when machining at a higher speed of 68 m min^?1 and depth of cut of 1.25 mm. This tool performance can generally be attributed to the difference in their ability to provide effective lubrication at the cutting zone, thermal conductivity of the coating materials as well as the cutting conditions employed. The uncoated carbide tools generally encountered more severe crater wear, chipping/fracture of the cutting edges as well as pronounced notching during machining. This is due to their inability to provide effective lubrication at the cutting zone, thus impeding the gliding motion of the chips along the rake and flank faces respectively, thus accelerating flank wear. Analysis of the worn tool edges revealed adhesion of a compact “fin-shaped” structure of hardened burrs with saw-tooth like edges. This generally alters the initial geometry of the cutting edge, consequently resulting to poor surface finish with prolonged machining.     

涂层硬质合金齿圆锯片的设计与试验

以锯片的实际锯切工况为背景,为适应不同成分钢材工件的锯切要求,选取无涂层硬质合金齿圆锯片以及分别涂覆有TiAlN和A1CrN的涂层硬质合金齿圆锯片作为研究对象,对三种锯片锯切试验的结果进行分析。分析结果表明：涂层硬质合金锯片可使锯片的锯切能力显著提升,使用寿命进一步提高;而且A1CrN涂层比TiAlN涂层更适合锯切难加工金属材料,从而为刀具涂层技术在锯切领域的应用奠定了基础。     

The effect of welding atmosphere on the pitting corrosion of AISI 304L resistance spot welds

In industry, many taper shafts are designed with tolerances of a few microns. To cut them in finish turning, paths of the tool in virtual machining should be accurately generated beforehand. For this purpose, the dimension errors and surface roughness of the virtually cut workpiece should be predicted. Unfortunately, the current tool path generation methods cannot accurately calculate the errors and the roughness, resulting in the taper errors larger than the part tolerance. Our research formulates equations of the effective turning edge to accurately calculate the dimension errors and the surface roughness, and then proposes a new approach to CNC programming for high-precision CNC turning. It lays a theoretical foundation of modeling parts in virtual turning and can generate tool paths to machine taper parts with high accuracy.     

SLM成形表面织构对TC4钛合金干摩擦磨损性能的影响

基于一步法思路,采用金属3D打印机基于激光选区熔化（SLM）技术制备表面带有凹坑织构的TC4钛合金试样,采用光学相机、超景深显微镜和扫描电镜观察织构成形情况,利用激光共聚焦位移测试仪和显微维氏硬度计分别测试表面粗糙度和表面硬度,在干摩擦条件下采用摩擦磨损试验仪考察不同载荷下织构密度对TC4钛合金试样摩擦学性能的影响,并使用扫描电镜对摩擦实验前后的表面形貌进行分析。研究结果表明：一步法SLM成形能够在TC4钛合金表面获得成形良好的直径500 μm的织构;随着织构密度的提高,钛合金试样表面粗糙度增大,表面硬度有所降低;干摩擦条件下,提高TC4钛合金试样织构密度有利于磨屑的收集从而减少试样的三体磨损,提高载荷有利于改善摩擦副接触状态;5 N载荷下40%织构密度试样的平均摩擦因数和磨痕宽度均最小,与无织构试样相比,平均摩擦因数和磨痕宽度分别降低12%和16%;40%织构密度下,载荷提高会引起摩擦因数的降低和磨损量增大,磨损表面犁沟和片状剥落增多。在干摩擦条件下,3D打印一步法制备的表面织构可以显著改善TC4钛合金的磨粒磨损和黏着磨损。     

Properties of coatings based on Cr,Ti, and Mo nitrides with embedded metals deposited on cutting tools

The relation between the phase-structure state and mechanical and operating characteristics of coatings based on solid solutions of (Ti, Cr)N, (Ti, Mo)N with Cr and Mo formed on a hard tool T15K6 alloy by condensation and ion bombardment of combined plasma flows in nitrogen is studied. A tool with the coating based on the solid solution (Ti, Cr)N is shown to have high hardness, low friction coefficient, and maximal resistance to cracking and oxidation, resulting in increased service life in mechanical working of steel.     

涂层钻头加工不锈钢磨损机理研究

研究了TiN、TiAlN、TiCN三种高速钢涂层专用麻花钻头钻削加工1Cr18NigTi奥氏体不锈钢时的刀具寿命以及刀具表面涂层的磨损特性。通过研究刀具寿命以及对刀具前刀面涂层磨损形态和元素成分的变化规律，揭示了三种涂层钻头的磨损机理。结果表明：在中低速、湿切削的情况下，TiCN涂层要优于TiAlN涂层，明显优于TiN涂层；TiCN涂层高速钢专用钻头较TiAlN、TiN涂层高速钢专用钻头更加适合不锈钢的钻削加工。研究结果对提高不锈钢钻削加工效率与加工质量具有重要意义。     

钢铜摩擦副摩擦磨损特性的试验研究

本文试验分析了ＺＱＡ１９－４和ＺＱＺｎ６－６－３两种铜合金材料在不同的表面粗糙度下对摩擦系数和出口区油温的影响，以及改变载荷和相对滑动速度时，摩擦系数的变化状况。结果表明；铜合金成分不同时具有不同的硬度。     

On dry sliding friction and wear behaviour of PEEK and PEEK/SiC-composite coatings

In this work, polyetheretherketone (PEEK) and PEEK/SiC-composite coatings were deposited on Al substrates using a printing technique to improve their surfaces performance. The objective of this work was to investigate coatings friction and wear behaviour. Especially, the effect of sliding velocity and applied load on coatings friction coefficient and wear rate was evaluated in range of 0.2-1.4 m/s and 1-9 N, respectively. Compared to Al substrate, the coated samples exhibit excellent friction coefficient and wear rate. For PEEK coating, under an applied load of 1 N, the increase in sliding velocity can result in decreasing of friction coefficient at a cost of wear resistance. Under a load of 9 N, however, PEEK coating exhibits the highest friction coefficient and wear rate at an intermediate velocity. These influences appear to be mainly ascribed to the influence of contact temperature of the two relative sliding parts. In most test conditions, the composite coating exhibits better wear resistance and a little higher friction coefficient. SiC reinforcement in composite coating plays a combined role. First of all, it might lead to energy dissipation for activation of fracture occurred on the interface of PEEK and the powders. Moreover, it can reduce coating ploughs and the adhesion between the two relative sliding parts.     

化学镀Ni—B合金与有机钼对金属基体的双重保护

采用表面镀层和润滑油中加入某些添加剂，使两者产生协同效应，是减少相对运动的零件表面间摩擦磨损的一项有效措施，本文研究了Ｎｉ－Ｂ合金镀层与油溶性有机钼的联系及摩擦磨损机理，摩擦磨损实验结果表明，Ｎｉ－Ｂ合金镀层与油溶性有机钼（ＭｏＤＴＰ）有良好的协同效应，可大幅度提高运动副的减摩性和耐磨性，如Ｎｉ－Ｐ合金镀层经４０℃热处理，油中加ＭｏＤＴＰ比４５钢基础油润滑下，耐磨性提高１２．８倍，摩擦系数降低５４