40Cr钢高效深磨磨削力试验研究

通过对40Cr钢在高效深磨条件下磨削力的试验研究，分析了不同工况对磨削力变化的影响，提出了40Cr钢高效深磨工艺参数的优化方案。试验结果表明，40Cr钢在高效深磨条件下，磨削力随磨削深度的变化呈波浪式的起伏而非线性关系，随砂轮线速度的提高而明显减少。同时证明，高效深磨条件下能获得比普通磨削大得多的比材料磨除率和较好的工件表面质量。     

超细晶粒硬质合金磨削的材料去除机理研究

在使用金刚石砂轮的平面磨床上进行了超细晶粒WC-Co硬质合金的磨削实验研究,通过扫描电子显微镜观察磨削表面形貌,利用X射线能谱仪进行磨削表面元素微区分析,对不同磨削条件下超细硬质合金的材料去除机理进行了研究。研究结果表明:超细硬质合金磨削过程中,随砂轮粒度的增大或切深的增加,材料去除方式渐由滑擦、耕犁向脆性断裂、材料粉末化转变。磨削表面黏结相分布受材料去除方式的影响,以耕犁方式去除的磨削表面Co相分布不均匀程度最大。     

硬质合金整体刀具外圆磨削加工表面缺陷分析

亚微、超细和纳米晶硬质合金是硬质合金整体刀具的典型材质，磨削加工表面缺陷会严重影响其使用寿命和服役行为的稳定性。本文分析了硬质合金整体刀具外圆磨削加工表面存在的4种典型缺陷及其形成原因，即磨屑表面粘附、表面条状撕裂、黏结相浸出和次表层裸露、WC晶粒碎裂。剖析了硬质合金整体刀具磨削加工的特殊性，即（1）合金中易存在以Co池和WC晶粒异常长大为典型代表的微观缺陷；（2）高矫顽磁力导致的难消磁特性；（3）高硬度和高强度导致的磨削碎屑的强损伤力；（4）低热导率和强磨削力工况条件对磨削液施载效果的严要求；（5）微观缺陷与磨削液的交互作用可促进黏结相和硬质相的电偶腐蚀和磨削表面Co的浸出；（6）强磨削力和WC本征脆性共同作用下，WC微小碎粒的形成对高效排屑的严要求。在棒材材质质量控制、磨削加工、磨屑处置、加工工序、磨削液选择与使用、磨削后处理和产品包装等方面提出了一系列抑制与预防磨削加工表面缺陷的建议。     

高效深磨的三种解析热模型

表达了三种高效深磨的热模型，分别是圆弧热源模型、均匀热源模型和三角形热源模型。用实验方法和理论计算方法研究了在高效深磨条件下磨削区的最高磨削温度。为了用高效深磨方式研究低合金钢的磨削性能，进行了平面磨削实验，测得了高效深磨条件下磨削区的最高磨削温度，并与用本模型计算结果进行了比较，发现实验结果与采用本模型理论计算结果基本一致，证明了该磨削热模型是正确的。     

硬质合金PA30高速深磨过程中声发射信号特征的变化研究

在硬脆难加工材料硬质合金PA30高速深磨声发射实验中,随着工件速度和磨削切削深度增加,声发射信号特征参数均方根（AE_RMS）和磨削力变大;随着砂轮速度增大,AE_RMS和磨削力减小。磨削力和AE_RMS有相同的变化趋势。硬质合金PA30高速深磨AE频谱的能量在100~600kHz的频段比较集中,其AE信号频谱的能量与频率范围明显高于低速浅切磨削。      

干/湿磨条件下HIPSN陶瓷磨削力实验研究

研究金刚石砂轮对HIPSN陶瓷平面磨削过程中,不同工艺参数对磨削力的影响。通过正交实验,在干/湿磨两种条件下研究砂轮线速度、磨削深度、工件进给速度等工艺参数对磨削力的影响。在其他参数不变的条件下,湿磨时的法向磨削力大于干磨时的法向磨削力,湿磨时的切向磨削力小于干磨时的切向磨削力。湿磨时的磨削力比大于干磨时的磨削力比,湿磨时的比磨削能小于干磨时的比磨削能。在一定条件下,干磨时的磨削力更有助于高精度表面质量的形成,为绿色加工和生产实践提供了一定的指导意义。     

硬质合金磨削力的实验研究

对硬质合金YG6、YT30的精密磨削进行了磨削力的实验研究．测定和分析了实际摩削深度、工作台速度与单位磨削力的对应关系；比磨削能与工作台速度、实际磨削深度的对应关系，以及比磨削能力与去除量之间的对应关系，并将YG6和YT30分别进行了比较。实验证明，单位磨削力随工作台速度和实际磨削深度的增加而增加。比磨削能随工作台速度和实际磨削深度，以及材料去除率的增加而降低。在同样磨削参数条件下，YG6的单位磨削力和比磨削能要大于YT30．     

钢结硬质合金的超精密磨削

本文提出了一种用机械化学磨削实现钢结硬质合金ＧＴ３５超精密磨削的方法，研究了机械化学磨削机理。研制出一种适合于ＧＴ３５超精磨密削用的磨削液，用这种磨削液要吧实现用带有石墨填充的树脂结合剂刚石砂轮进行超精密磨削硬质材料ＧＴ３５。磨削后表面粗糙度Ｒａ，Ｒｚ值低（Ｒａ＝０．０１７μｍ，Ｒｚ＝０．０８５μｍ），表面质量好。本文比较了用不同磨削液冷却时磨削后的表质量，确定了新研制磨削液的磨削效果。同时还研究     

电解磨削在硬质合金工具生产中的应用

电解磨削是近十几年来迅速发展起来的一种新工艺,它对于磨削硬质合金和各种难加工的耐热合金等材料,具有良好的效果。我厂自从1966年以来,在工具生产中加工各种硬质合金工具,如硬质合金的车刀、铰刀、铣刀、不重磨拉刀和硬质合金拉丝模等等,已经广泛采用,而且正常地用于生产,在生产上发挥了很大作用。目前,采用电解磨削的机床已有电解车刀磨床,电解万能外圆磨床,电解万能工具磨床,电解卧式、立式平面磨床,电解内     

氮化硅陶瓷干湿磨削温度与表面质量研究

为研究干湿磨两种条件下氮化硅陶瓷温度场特性,以及磨削力、温度场特性与表面质量三者间的关系。在理论分析的基础上运用ABAQUS有限元软件对其进行仿真,最后通过实验分析干湿磨条件下的温度场对其表面特性的影响。得出在干湿磨两种条件下的磨削力与磨削区温度场的关系以及磨削温度场的分布情况;并分析了温度场对其热裂纹的影响与温度和其表面特性的关系。得出磨削力是影响磨削区温度场变化的主要因素;随着磨削表面下深度的增加,湿磨下磨削温度的幅度变化要大于干磨,且磨削温度的幅度变化对其表面特性与裂纹的产生有所影响;干磨条件下的表面粗糙度与微观形貌要优于湿磨条件下。     

Influence of the cemented carbide specification on the process force and the process temperature in grinding

Cemented carbides are hard and brittle materials. Their material properties are adjusted by their chemical composition, in particular their average hard phase grain size and their binder fraction. The research paper focusses on grinding of cemented carbides with cobalt (Co) as binder and tungsten carbide (WC) as hard phase material. Within the research paper, it is discussed if and to what extent the cemented carbide composition affects the occurring thermo-mechanical load collective in the grinding process. In particular, the influence of the average WC grain size and the cobalt fraction on the thermo-mechanical load collective is investigated and explained by the cemented carbide material properties. The results of the publication contribute to a knowledge-based design of cemented carbide grinding processes.     

Influence of surface topography evolution of grinding wheel on the optimal material removal rate in grinding process of cemented carbide

Most of the reported studies on the optimization of grinding parameters do not consider the evolution of the surface topography of grinding wheels, and the established empirical models will no longer apply when the surface conditions of the grinding wheel changes. In this paper, an integrated model based on the surface topography of grinding wheel is established. The grinding process of cemented carbide is simulated using the established model, and the simulation results are analyzed to obtain the surface roughness model and the specific grinding energy model based on the undeformed chip thickness distribution. Subsequently, the grinding constraint models are defined according to the two grinding constraints—surface roughness and specific grinding energy. Through inversion analysis, the maximum material removal rate of the given grinding wheel surface conditions satisfying the defined grinding constraints are obtained, and the influence rules of the grinding wheel surface conditions on the maximum material removal rate are analyzed. Then the grinding wheel surface conditions are adjusted by changing the radial dressed height of the grinding wheel and the arrangement distance of the grains in wheel circumferential direction to improve the maximum material removal rate of the grinding wheel. Finally, the optimization results are verified through grinding tests of cemented carbide.     

A study of grinding silicon nitride and cemented carbide materials with diamond grinding wheels

This paper presents selected results of the grinding of silicon nitride and cemented carbide materials with diamond grinding wheels, which will in later research be extended to the grinding of ceramic-cemented carbide compound drill tools. In these fundamental experiments four different types of diamond grinding wheels were used in face grinding processes. The diamond grinding wheels vary by the grain size, the grain concentration and the bonding material. The relevant influencing variables such as the cutting and feed speed and the coolant supply method were varied to investigate the effect on grinding of the two different workpiece materials, the brittle silicon nitride workpiece material and the ductile cemented carbide workpiece material. Some factors, which have significant effects, like the radial wear of the grinding wheel, the components of the grinding forces, the normal and the tangential grinding force, and the surface quality of the ground workpieces are discussed in detail.     

Influence of microstructure on ultraprecision grinding of cemented carbides

The influence of microstructure on the ultraprecision grinding response of a series of cemented carbides for spherical mirrors was characterized by means of optical and laser interferometry, atomic force microscopy, scanning electron microscopy and X-ray diffraction. Surface roughness, form accuracy, grinding-induced residual stress and material removal behaviors were studied as a function of tungsten carbide (WC) grain size. In connection with the removal mechanisms in ultraprecision grinding, microindentations performed on each material showed similar deformation patterns, all in the plastic regime. The microstructure of WC-Co materials was found to have little influence on the nanometre surface roughness and submicron form accuracy. However, the X-ray stress measurements indicated that the microstructure of carbide materials had a significant influence on the grinding-induced residual stresses; i.e. an increase in grinding-induced residual compressive stress with an decrease in WC grain size. No grinding-induced cracks were observed in the ground cemented carbide surfaces. The material removal in ultraprecision grinding was considered to occur within the ductile regime. The formation of microgrooves and plastic flow regions via slip bands of WC grains along the cobalt binder without visible resultant microfracturing of WC grains were the dominant removal mechanisms.     

–50 ℃冷风条件下抛光硬质合金刀片加工TC4钛合金的表面粗糙度分析

目的提高硬质合金刀片加工TC4钛合金的表面质量。方法利用化学机械抛光技术对传统磨削的硬质合金刀片分别进行粗抛、半精抛和精抛处理,运用正交试验法,在常温干切和–50℃冷风条件下,分别采用传统磨削的硬质合金刀片(磨削刀片)与化学机械抛光的硬质合金刀片(抛光刀片)进行切削TC4钛合金正交试验,利用方差分析法分析切削参数对已加工表面粗糙度Ra的影响。运用多元线性回归方法建立磨削刀片、抛光刀片在常温干切和–50℃冷风条件下切削TC4钛合金已加工表面粗糙度Ra的经验预测模型。结果硬质合金刀片前刀面通过粗抛、半精抛和精抛后,刀片前刀面的表面粗糙度Ra为19 nm。当切削参数相同时,磨削刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度,比常温干切条件下平均降低了35.9%;抛光刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度,比常温干切条件下平均降低了43.5%。在常温干切条件下,抛光刀片比磨削刀片切削TC4钛合金的已加工表面粗糙度平均降低了19.2%;在–50℃冷风条件下,抛光刀片比磨削刀片切削TC4钛合金的已加工表面粗糙度平均降低了28.7%。抛光刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度Ra,比磨削刀片在常温干切条件下切削TC4钛合金的已加工表面粗糙度Ra平均降低了54.4%。结论采用对硬质合金刀片表面进行化学机械抛光技术和以–50℃冷风为切削介质的组合工艺,可有效降低TC4钛合金已加工表面粗糙度。     

抛光涂层硬质合金刀片加工钛合金的耐用度分析

目的提高涂层硬质合金刀具加工钛合金的切削性能及加工效率。方法采用化学机械抛光(Chemical Mechanical Polishing,CMP)对经过磨削加工的YG8硬质合金车削刀片前刀面进行抛光预处理,并使用CVD与PVD涂层工艺制备涂层。运用单因素试验法,对抛光涂层硬质合金刀片进行切削TC4钛合金的刀片耐用度试验,分析钛合金加工过程中刀具种类及切削参数变化对刀片耐用度的影响规律。采用扫描电子显微镜(SEM)和能谱仪(EDS)分析刀片的磨损机理。结果经过化学机械抛光处理后,硬质合金刀片的平均粗糙度由87 nm降低为19 nm,降低幅度达78.2%。相同切削参数时,抛光CVD硬质合金刀片的耐用度最大程度上比磨削CVD硬质合金刀片提高了75%,抛光PVD硬质合金刀片的耐用度最大程度上比磨削PVD硬质合金刀片提高了8.3%。可见采用化学机械抛光对硬质合金刀片进行加工是提高刀片表面平整度及耐用度的重要途径。结论抛光CVD硬质合金刀片的耐用度优于磨削CVD硬质合金刀片,抛光PVD硬质合金刀片的耐用度优于磨削PVD硬质合金刀片。     

纳米硬质合金磨削温度及热量分配比例试验研究

为了对纳米硬质合金磨削温度及热量分配比例进行深入研究,同时探讨不同粒度硬质合金间的差异,为多种粒度硬质合金的磨削加工及质量控制提供参考,选择以纳米硬质合金GU092为主的3种硬质合金进行磨削试验。结果表明：相比普通硬质合金,纳米硬质合金的磨削温度较低,热量分配比例较高,在2.5%～11.8%之间;磨削温度随晶粒度变细而降低,且细粒度材料表面的塑性变形小,磨削时消耗的能量更少;热量分配比例随着晶粒度的变细而增加,细粒度硬质合金的物理机械性能更强,导热性能更好。在考虑加工效率的前提下,适当降低磨削深度、增大进给速度,有助于降低温度、提高质量。     

铸铁结合剂金刚石砂轮ELID磨削硬质合金的性能研究

硬质合金具有硬度高、强度好、耐腐蚀和耐磨损的特点,采用传统方法难以满足精密及超精密加工的技术要求.本文采用不同粒度的铸铁结合剂金刚石砂轮ELID镜面磨削硬质合金,得到了不同加工效率以及不同加工表面质量的硬质合金磨削效果,揭示了不同粒度砂轮其磨削性能变化的规律与作用.实验结果表明:在相同的进给量下,粗粒度砂轮的磨削效率较高,能更好地控制工件的尺寸精度.细粒度砂轮则磨削效率较低,但能获得优良的加工表面质量.砂轮表面的氧化膜在磨削过程中扮演非常重要的角色,磨粒的粒径与砂轮表面氧化膜厚度的比值大小决定了砂轮的磨削性能.氧化膜的形成又受到电解参数的影响,可以通过对电解参数的调节实现高效率高精度的ELID磨削.     

含三乙醇胺磨削液对硬质合金刀具的危害

用三种磨削液对硬质合金刀具进行了磨削实验 ,磨削后的刀具表面用扫描电镜进行了成分分析 ,磨削液中的钴含量用分光光度法进行了测定。实验结果表明 ,含三乙醇胺的磨削液对硬质合金有较大的危害