干式车削不同淬硬状态工具钢三向切削力的试验研究

通过使用PCBN刀具精密干式车削不同淬硬状态(51、55、58、62、65±1 HRC)工具钢Cr12MoV的试验,分析了淬硬状态对三向切削力的影响规律。试验表明:随工件硬度的升高,主切削力与径向力先逐渐增大,后急剧减小;而进给力在很小范围内波动。EDS分析进一步表明:工件硬度达到65±1 HRC时,会因工件表面材料的脆性而减小切削力;而当工件硬度达到62±1 HRC时,由于切削温度的升高而在切屑与刀具前面产生粘结作用,从而引起切削力增大。试验结果对精密干式切削淬硬工具钢具有实际的指导意义与参考价值。     

精密干式硬态车削淬硬工具钢时表面粗糙度的参数优化

使用PCBN刀具对不同淬硬状态工具钢Cr12MoV进行了精密干式硬态车削试验,运用正交实验法分析了切削速度、试件硬度、刀具前角、切削深度4个因素间的交互作用,并得到了最优车削参数.试验表明:影响表面粗糙度最显著的因素是切削速度与淬火硬度,切削深度影响最小.     

精密干式硬态车削淬硬工具钢加工表面温度参数优化

使用PCBN刀具对不同淬硬状态工具钢Cr12MoV进行精密干式硬态车削试验,运用极差法分析切削速度、走刀量、切削深度、试件硬度、刀尖圆弧半径五个因素对工件表面温度影响的显著性,并得到了最优车削参数。试验表明：影响工件表面温度最显著的因素是工件淬火硬度,切削深度与走刀量的影响相当,刀尖圆弧半径的影响最小。     

干式车削不同淬硬状态淬硬钢已加工表面粗糙度及三维形貌的试验研究

使用 PCBN 刀具对5种不同淬硬状态(40±1HRC,45±1HRC,50±1HRC,55±1HRC,60±1HRC)Cr12MoV模具钢进行干式硬态车削试验,揭示了切削速度、走刀量、切削深度、工件硬度对已加工表面粗糙度及三维形貌的影响规律及机理.研究结果表明:与车削硬度为40±1HRC、45±1HRC、60±1HR...     

淬硬零件的车削

代替磨削的硬车削,比磨削效率高很多倍。例如,修磨一件螺纹滚子,磨削需要2小时,而硬车削只需10min。     

硬态干式车削淬硬钢SKD11表面粗糙度试验研究

应用单因素法研究了PCBN 刀具硬态干式切削淬硬钢SKD11过程中,进给量、切削速度、背吃刀量、刀尖圆弧半径和倒棱宽度等参数对表面粗糙度的影响规律.     

基于神经网络的高速硬车削切削力预测研究

采用PCBN刀具进行高速硬车削AISI P20淬硬钢的切削试验,并通过方差分析研究切削速度、进给量、切削深度和刀尖圆弧半径对切削力的影响.基于获得的试验数据,应用人工神经网络方法建立高速硬车削P20淬硬钢时的切削力预测模型.试验与仿真分析显示,切削力随进给量、切削深度和刀尖圆弧半径的增加而增大,而不同切削速度下的切削力值几乎保持不变;同时,切削深度对切削力的影响最为显著,其次为进给量,再次为刀尖圆弧半径,而切削速度的影响则非常微弱.     

高速铣削P20和45淬硬钢的切削力

使用TiAlN涂层的整体硬质合金球形立铣刀，对45钢（52HRC、48HRC、42HRC）及P20钢（41HRC、33HRC）进行了高速铣削试验。基于材料变形下的流动应力方程及剪切角理论，分析了切削速度、工件硬度、材料性能对切削力的影响。试验中的切削参数如下：切削速度为156～816m／min，每齿进给量为0．1mm，轴向切削深度为3mm，切削宽度为1mm。结果表明：高速铣削淬硬钢产生锯齿形切屑，切削速度和工件硬度对切削力有显著影响。     

用PCBN车削淬硬钢工件

有时硬车削是精加工淬硬钢工件的最好方法。     

切削用量对车削40CrNiMo切削力影响的仿真研究

利用有限元分析软件ABAQUS建立了车削40Cr Ni Mo的有限元模型,并在不同切削用量条件下对切削力进行仿真,得到了主切削力、进给力的变化规律,分析了引起切削力变化的主要原因。结果表明:切削分力中主切削力最大;切削深度对切削力尤其是主切削力的影响最大,进给量次之,切削速度的影响最弱。     

Prediction of tool failure rate in turning hardened steels

This paper presents a stochastic model for predicting the tool failure rate in turning hardened steel with ceramic tools. This model is based on the assumption that gradual wear, chemical wear, and premature failure (i.e. chipping and breakage) are the main causes of ending the tool life. A statistical distribution is assumed for each cause of tool failure. General equations for representing tool-life distribution, reliability function, and failure rate are then derived. The assumed distributions are then verified experimentally. From the experimental results, the coefficients of these equations are determined. Further, the rate of failure is used as a characteristic signature for qualitative performance evaluation. The results obtained show that the predicted rate of ceramic tool failure is 20% (in the first few seconds of machining) and it increases with an increase in cutting speeds. These results indicate that there will always be a risk that the tool will fail at a very early stage of cutting. Such a possibility should not be overlooked when developing proper tool replacement strategies. Finally, the results also give the tool manufacturers information which can be used to modify the quality control procedures in order to broaden the use of ceramic tools.Nomenclature c constant - ch chamfer width of the tool, mm - d depth of cut, mm - h _i hardness value at theith location on the workpiece during machining - h mean ofh ₁,h ₂,h ₃, ...,h _nn - n hardness mean location - m Meyer exponent determined experimentally to define the nonlinear relation between the cutting force and the ratioh _i/h - f feedrate, mm rev^–1 - f(t) probability density function of tool failure - f ₁(t) probability density function of tool failure due to breakage caused by tool quality - f ₂(t) probability density function of tool failure due to breakage caused by workpiece condition - f ₃(t) probability density function of tool failure due to tool chipping caused by chemical wear - f ₄(t) probability density function of tool failure due to flank wear - f ₅(t) probability density function of tool failure due to crater wear - O() error - t cutting time, min - x ₁,x ₂,...,x _n independent variables - A _i instantaneous area of contact between the tool and the workpiece - C ₁ chip load, which can be determined as a function of the cutting conditions and tool geometry - K _I crater wear index - K _T maximum depth of crater wear on tool face, mm - K _M crater centre distance, mm - N number of failures - P(t) probability function of tool failure - P _j(t) corresponding probability of failure, such that 1j5 - R tool nose radius, mm - R(t) reliability function - R _j(t) corresponding reliability function, such that 1j5 - T _V estimate of tool life for a set value of average flank wear (V _B ^* ) - T _K estimate of tool life for a set value of maximum depth of crater wear (K _T ^* ) - V cutting speed, m/min - V _B average tool wear, mm - Z(t) instantaneous failure rate or hazard function - ₃ shape parameter in the Weibull probability density function - rake angle - ₃ scale parameter in the Weibull probability density function, min - failure rate of the cutting tool - mean of a logarithmic normal distribution function - standard deviation of a logarithmic normal distribution function - tool wear function - time corresponding to the occurrence of tool failure - (.) standard logarithmic normal distribution function     

Wear behavior of some cutting tool materials in hard turning of HSS

This study presents an assessment of the performance of four cutting tool in the machining of medium hardened HSS: polycrystalline c-BN (c-BN+TiN), TiN coated polycrystalline c-BN (c-BN+TiN), ceramic mixed alumina (Al₂O₃+TiC), and coated tungsten carbide (TiN coated over a multilayer coating (TiC/TiCN/Al₂O₃)). The Al₂O₃+TiC and the coated carbide tools can outperform both types of c-BN at high cutting speeds. Raman and SEM mapping revealed an alumina tribo-layer that protects the surface of the Al₂O₃+TiC cutting tool. The high chemical and thermal stability of Al₂O₃ tribo-films protects the tool substrate because it prevents the heat generated at the tool/chip interface from entering the tool core.     

高速硬车削淬火钢的实验研究

通过改变高速车削淬火钢（Cr12）的切削用量，对切削力、切削温度、加工表面质量等进行了研究，结果表明合理选择切削用量，高速硬车削淬火钢可显著提高生产率及加工表面质量，并在一定程度上可取代磨削加工。     

高速硬车削淬火钢的实验研究

通过改变高速车削淬火钢(Cr12)的切削用量,对切削力、切削温度、加工表面质量等进行了研究,结果表明合理选择切削用量,高速硬车削淬火钢可显著提高生产率及加工表面质量,并在一定程度上可取代廖削加工。     

Effect of work material hardness and cutting parameters on performance of coated carbide tool when turning hardened steel: An optimization approach

In present work performance of coated carbide tool was investigated considering the effect of work material hardness and cutting parameters during turning of hardened AISI 4340 steel at different levels of hardness. The correlations between the cutting parameters and performance measures like cutting forces, surface roughness and tool life, were established by multiple linear regression models. The correlation coefficients found close to 0.9, showed that the developed models are reliable and could be used effectively for predicting the responses within the domain of the cutting parameters. Highly significant parameters were determined by performing an Analysis of Variance (ANOVA). Experimental observations show that higher cutting forces are required for machining harder work material. These cutting forces get affected mostly by depth of cut followed by feed. Cutting speed, feed and depth of cut having an interaction effect on surface roughness. Cutting speed followed by depth of cut become the most influencing factors on tool life; especially in case of harder workpiece. Optimum cutting conditions are determined using response surface methodology (RSM) and the desirability function approach. It was found that, the use of lower feed value, lower depth of cut and by limiting the cutting speed to 235 and 144 m/min; while turning 35 and 45 HRC work material, respectively, ensures minimum cutting forces, surface roughness and better tool life.     

Effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and forces in finish turning of hardened AISI H13 steel

In this study, the effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and resultant forces in the finish hard turning of AISI H13 steel were experimentally investigated. Cubic boron nitrite inserts with two distinct edge preparations and through-hardened AISI H13 steel bars were used. Four-factor (hardness, edge geometry, feed rate and cutting speed) two-level fractional experiments were conducted and statistical analysis of variance was performed. During hard turning experiments, three components of tool forces and roughness of the machined surface were measured. This study shows that the effects of workpiece hardness, cutting edge geometry, feed rate and cutting speed on surface roughness are statistically significant. The effects of two-factor interactions of the edge geometry and the workpiece hardness, the edge geometry and the feed rate, and the cutting speed and feed rate also appeared to be important. Especially honed edge geometry and lower workpiece surface hardness resulted in better surface roughness. Cutting-edge geometry, workpiece hardness and cutting speed are found to be affecting force components. The lower workpiece surface hardness and honed edge geometry resulted in lower tangential and radial forces.     

Experimental investigation of the three-component forces in finish dry hard turning of hardened tool steel at different hardness levels

In this paper, the effects of cutting speed, depth of cut, feed, workpiece hardness (51, 55, 58, 62, and 65?±?1 HRC), tool flank wear, and nose radius on three-component forces in finish dry hard turning (FDHT) of the hardened tool steel AISI D2 were experimentally investigated by utilizing the PCBN inserts. Experimental results showed that the feed force is the lowest in three-component forces and influence of cutting parameters on it is less than two others in the FDHT of AISI D2. Values of the radial force are higher than those of the cutting force when cutting speed, depth of cut, and feed range from 75 to 301 m/min, and 0.10 to 0.40 and 0.05 to 0.20 mm, respectively, but lower in the range between 0.8- and 1.6-mm nose radius. Values of the cutting force are higher than those of the radial force as the workpiece hardness varies from 51 to 58?±?1 HRC while lower in the range between 62 and 65?±?1 HRC. Besides, there are relations between the changing laws of three-component forces and the softening effect of chip, cohesion effect in the tool–chip junction zone, and intenerating effect of metal in the workpiece surface. The high flank wear formation increases the contact with workpiece surface and hence induces tearing–drawing and welding effect duo to instantaneous high temperature.     

Analysis of tool wear and surface finish in hard turning

Hard turning is a profitable alternative to finish grinding. The ultimate aim of hard turning is to remove work piece material in a single cut rather than a lengthy grinding operation in order to reduce processing time, production cost, surface roughness, and setup time, and to remain competitive. In recent years, interrupted hard turning, which is the process of turning hardened parts with areas of interrupted surfaces, has also been encouraged. The process of hard turning offers many potential benefits compared to the conventional grinding operation. Additionally, tool wear, tool life, quality of surface turned, and amount of material removed are also predicted. In this analysis, 18 different machining conditions, with three different grades of polycrystalline cubic boron nitride (PCBN), cutting tool are considered. This paper describes the various characteristics in terms of component quality, tool life, tool wear, effects of individual parameters on tool life and material removal, and economics of operation. The newer solution, a hard turning operation, is performed on a lathe. In this study, the PCBN tool inserts are used with a WIDAX PT GNR 2525 M16 tool holder. The hardened material selected for hard turning is commercially available engine crank pin material.