GH4169和K4169切削加工性能对比研究

GH4169与K4169分属变形镍基高温合金和铸造镍基高温合金，具有不同的成型工艺和热处理状态。开展了非涂层硬质合金刀具干切削GH4169和K4169的对比试验，从切削力、刀具磨损方面揭示了两种材料加工性能的差异，从力学性能及显微组织两方面解释了差异产生的原因。结果表明，试验各组参数下，两种材料切削力无显著差别；随着切削速度和进给量的增加，切削GH4169时刀具磨损形式由刀尖磨损过渡到后刀面均匀磨损最后转变成沟槽磨损，切削K4169时刀具失效形式主要为后刀面均匀磨损和沟槽磨损，并未出现严重的刀尖磨损，K4169组织中的C化物等硬质点是导致其切削力波动较大及刀具产生沟槽磨损的主要原因。     

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。     

切削介质对微细铣刀磨损影响的试验研究

在微细铣削加工中,尚缺乏切削介质对刀具磨损影响的研究.在干切削、浇灌切削液、微量切削液和低温冷风介质下,对6061铝合金进行了微细铣削试验,研究了刀具的磨损形式和机理、不同切削介质对刀具磨损、切削力和表面粗糙度Ra的影响规律.同时,确定出能减小刀具磨损和切削力,提高加工质量的最佳切削介质.结果表明:四种切削介质下刀具磨损的形式不完全相同,粘结磨损与磨粒磨损是造成刀具磨损的主要机理;切削力和表面粗糙度Ra的变化趋势可以辅助判断刀具磨损情况;相比于其它切削介质,微量切削液介质下刀具磨损小,切削力低,工件表面质量好,是微细铣削6061铝合金的最佳切削介质.为深入研究微细铣削刀具磨损和实际加工中选择切削介质有一定的参考价值.     

切削介质对微细铣刀磨损影响的试验研究

在微细铣削加工中,尚缺乏切削介质对刀具磨损影响的研究.在干切削、浇灌切削液、微量切削液和低温冷风介质下,对6061铝合金进行了微细铣削试验,研究了刀具的磨损形式和机理、不同切削介质对刀具磨损、切削力和表面粗糙度Ra的影响规律.同时,确定出能减小刀具磨损和切削力,提高加工质量的最佳切削介质.结果表明:四种切削介质下刀具磨损的形式不完全相同,粘结磨损与磨粒磨损是造成刀具磨损的主要机理;切削力和表面粗糙度Ra的变化趋势可以辅助判断刀具磨损情况;相比于其它切削介质,微量切削液介质下刀具磨损小,切削力低,工件表面质量好,是微细铣削6061铝合金的最佳切削介质.为深入研究微细铣削刀具磨损和实际加工中选择切削介质有一定的参考价值.     

复合Si3N4刀具切削高锰钢时的磨损、破损机理

研究了复合Si3N4刀具切削难加工的高锰钢时的磨损、破损机理。通过试验测量了刀具后刀面磨损宽度分别与切削时间和切削速度的关系，用扫描电镜显微分析了复合Si3N4的磨损和破损形貌和元素变化。结果表明，随着切削时间的延长，Si3N4刀具表面依次出现积屑瘤、扩散磨损和机械、扩散、粘结复合型磨损形式；刀具的破损形式分别发生在高速切削初期的脆性断裂和长时间切削导致的热震破裂；刀具的最佳切削速度为60-70m/min。     

硬质合金刀具高速干车削Ti6Al4V切削力及刀具寿命研究

主要对硬质合金刀具在较高的速度范围内干车削Ti6Al4V进行了正交试验。获得了干切削状态下切削力与刀具寿命的经验公式,分析了切削力、刀具磨损与切削路程-试验时间的关系,同时研究了刀具的磨损形态和磨损机理,粘结、扩散、氧化是硬质合金刀具的主要磨损机理。最后。通过对刀具寿命-切削效率的分析,给出了硬质合金刀具在干切削状态下合理的切削参数。     

高速切削Inconel 718刀具磨损形态和机理分析

利用涂层硬质合金刀具对Inconel 718进行了高速干切削试验,采用扫描电子显微镜SEM和能量分散光谱EDS扫描,对不同切削参数下刀具的损坏形态和损坏机理进行了研究。分析结果表明刀具损坏形式主要有前刀面磨损、后刀面磨损、剥落和崩刃。刀具损坏机理主要是粘结磨损、磨粒磨损、氧化磨损和扩散磨损等。     

硬质合金刀具切削各向同性热解石墨磨损机理

针对各向同性热解石墨切削过程中刀具磨损过快的问题,采用硬质合金刀具进行了切削加工试验,研究了切削过程中硬质合金刀具的磨损形式、磨损过程以及刀具磨损对表面加工质量的影响。通过对试验结果的研究分析表明:硬质合金刀具磨损形式为后刀面磨损以及切削刃崩刃破损,刀具磨损机理为磨粒磨损。刀具的有效切削距离仅为250m左右,已加工表面分布着形状和深度大小不一的凹坑,表面加工质量差,硬质合金刀具作为各向同性热解石墨的切削刀具具有一定的局限性。     

加工含镍球墨铸铁时梯度陶瓷刀具的失效机理

研究了Al2O3／TiC梯度陶瓷刀具干切削含镍球墨铸铁的切削性能及损坏机理。结果表明,梯度陶瓷刀具的寿命约为硬质合金YS10刀具的1—2倍,且切削速度愈高,梯度陶瓷刀具的优越性愈显著;其损坏形式：低速切削时,为磨粒磨损;高速切削时,为剥落及粘结磨损。     

PCBN刀具切削GCr15淬硬轴承钢时刀具磨损的研究

通过切削实验，研究了PCBN刀具切削淬硬轴承钢时刀具磨损形态及磨损机理。实验表明。PCBN刀具前刀面的磨损为月牙洼磨授，后刀面的磨损为机械磨损，其磨损程度与工件硬度呈非线性关系，并随着切削速度的提高磨损量减少。     

PCBN刀具干湿切削淬硬钢对比试验研究

通过PCBN刀具干、湿切削淬硬轴承钢GCr15对比试验,对两种条件下的切削力随刀具磨损的变化、刀具寿命及被加工工件表面粗糙度进行了对比。试验表明:干切削状态下金属软化效应占主导地位,湿切削可获得更好的表面粗糙度,切削液在刀具磨损后期开始发挥作用。     

Evaluation of machinability and economic performance in cryogenic-assisted hard turning of α-β titanium: a step towards sustainable manufacturing

Abstract

Titanium, a difficult-to-cut material, consumes higher time and cost in removing material by machining to produce parts. Machining of Ti alloys has got serious attention owing to its reactive nature with tool materials at elevated temperature that aggravates tool wear. Reportedly, effective and efficient cooling and lubrication at the tool–work interface can ameliorate the machinability of Ti-alloys. In this perspective, this article interrogates the underlying mechanism of critical responses such as surface roughness, temperature, tool life and machining cost under dry, minimum quantity lubrication (MQL) and cryogenic liquid nitrogen (LN2) modes. The effect of cutting speeds and feed rates on such responses have been considered as a function of cooling strategy to standardize the cooling technique as the best alternative for machining. Cryogenic cooling seems to be preponderant regarding machining cost, temperature, surface roughness and tool life in hard turning of a–b titanium alloy. The feasibility of cryogenic cooling was investigated using the iso-response technique in comparison with dry and MQL-assisted hard turning. Experimental results revealed longer tool life and lower machining cost under cryogenic condition followed by MQL and dry machining. Moreover, cryogenic LN2 has been identified as an appropriate alternative to reduce the temperature and surface roughness. On contrary, dry turning evoked a high-temperature and rapid tool wear. In a nutshell, cryogenic assisted hard turning has acceded as a sustainable strategy from an environmental and economic perspective.     

Study on lubricating characteristic and tool wear with water vapor as coolant and lubricant in green cutting

In recent years, green cutting is becoming increasingly more popular due to concern regarding the safety of the environment and operator health. The efficiency of metal cutting operation depends upon the frictional/thermal conditions at the tool–chip interface. Use of water vapor, gases (carbon dioxide, oxygen), WV&C (mixture of water vapor and carbon dioxide gas) and WV&O (mixture of water vapor and oxygen gas) as coolants and lubricants to improve the frictional/thermal conditions in turning operations are studied here. In this study, the effects of water vapor, gases, mixture of water vapor and gas, oil water emulsion applications and dry cutting on main cutting force, cutting temperature, chip deformation coefficient (count backwards of cutting ratio), rake face wear, and tool flank wear have been examined in turning ANSI 1045 steel material with cement carbide tool P10. Experimental results show that applications of water vapor, gases and mixture of water vapor and gas reduce main cutting force comparing to dry cutting and wet cutting. Water vapor reduces lower cutting temperature and chip deformation coefficient than others lubricating conditions. The tool life is extended much longer in direct on applications of water vapor and mixture of vapor and gas than dry cutting. The diffusion and adhesion is alleviated with application of water vapor because of chemical reaction between water vapor and metal surface and forming boundary lubrication layer of multi-dimension metal oxidation.     

The analysis of tool life and wear mechanisms in spindle speed variation machining

Regenerative chatter vibrations generally limit the achievable material removal rate in machining. The diffusion of spindle speed variation (SSV) as a chatter suppression strategy is mainly restricted to academy and research centers. A lack of knowledge concerning the effects of non-stationary machining is still limiting its use in real shop floors. This research is focused on the effects of spindle speed variation technique on tool duration and on wear mechanisms. No previous researches have been performed on this specific topic. Tool wear tests in turning were carried out following a factorial design: cutting speed and cutting speed modulation were the investigated factors. The carbide life was the observed process response. A statistical approach was used to analyze the effects of the factors on the tool life. Moreover, the analysis was extended to the wear mechanisms involved during both constant speed machining and SSV. The worn-out carbide surfaces were examined under a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. Significant differences were appreciated. It was observed that SSV tends to detach the coatings of the inserts, entailing a mechanism that is quite unusual in wet steel turning and thus fostering the wear of the tool. The performed analysis allowed to deduce that the intensified tool wear (in SSV cutting) is mainly due to thermo-mechanical fatigue.     

不同冷却条件下钛合金材料的车削性能研究

对难加工材料钛合金进行冷风油雾切削实验,将实验结果与常温干车、常温喷雾和大量油剂喷淋的冷却方式进行对比研究。通过实验结果分析,在采用相同切削参数及刀具加工时,低温喷雾冷却的刀具使用寿命最长,常温干车的刀具使用寿命最短。同时,采用低温喷雾冷却方法,加工表面粗糙度值也有所下降。     

Environmentally conscious hard turning of cemented carbide materials on the basis of micro-cutting in SEM: stressing four kinds of cemented carbides with PCD tools

Environmentally conscious hard turning and technology has placed more importance on the machining process. In this research, the possibility of environmentally conscious hard turning of cemented carbides was studied. The effects of cutting methods of dry and wet (vegetable oil mist, and mineral oil) and work material on cutting resistance and wear characteristics of cutting tools were experimentally investigated. The turning and micro-cutting process in SEM was carried out by using four kinds of tungsten carbides with the PCD cutting tools. Specifically, an emphasis was put on the effect of WC and Co additives in four kinds of cemented carbides on machinability and tool wear characteristics. The tool wear width and the cutting resistances were measured, and the worn flank was observed.     

高合金不锈钢的干车削和近干车削研究

高合金不锈钢具有强度高、韧性好、耐腐蚀等优良性能而得到日益广泛的应用,但是其难加工性同时也对切削技术提出了更高的要求.干切削因具有对环境和人体无害、经济性好等优点成为金属加工技术的主要发展方向之一.文中对高合金不锈钢Y12Cr17和16Cr17Ni3的干车削和近干车削中,切削参数和切削材料对刀具磨损和工件表面质量的影响进行了深入研究.结果表明,通过选择适当的切削参数、刀具材料以及刀具涂层,可以很好地实现高合金不锈钢的干车削加工,并能获得比传统乳化剂加工更小的磨损值和更好的工件表面质量.     

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。     

干式高速车铣时金属陶瓷刀具磨损机理研究

研究了干式高速车铣D60钢时金属陶恣刀具的磨损机理和磨损特性。与水溶性冷却液浇注冷却的湿式高速车铣相比,干式高速车铣D60钢时,金属陶瓷刀具有更高的耐磨性。硬质相颗粒的脱落是干式高速车铣D60钢时金属陶瓷刀具磨损的主要原因。     

Minimal quantity lubrication in turning: Effect on tool wear

Industries and researchers are trying to reduce the use of coolant lubricant fluids in metal cutting to obtain safety, environmental and economical benefits. The aim of this research is to determine if the minimal quantity lubrication (MQL) technique in turning gives some advantages in terms of tool wear reduction. This paper reports the results obtained from turning tests and SEM analysis of tools, at two feed rates and two cutting lengths, using MQL on the rake and flank of the tool. The results obtained show that when MQL is applied to the tool rake, tool life is generally no different from dry conditions, but MQL applied to the tool flank can increase tool life.