Effect Of Workpiece Hardness Research Articles

A study on Effect of Surface Finishing Processes on Surface Roughness of AISI D2 Tool Steel

According to recent studies, dry hard turning is more beneficial practical process compared to a grindingoperation, it increases quality, reduces cost and lead-time formachined parts. In this study, effects of workpiece hardness,feed rate, depth of cut and cutting speed on surface roughnesswere studied using chamfered and honed CBN inserts. Fourfactors (hardness, depth of cut, feed rate and cutting speed)were considered and - two level fractional experiments wereconducted and analysis of the variance was performed.Furthermore this study shows that the effects of grinding ofheat treated AISI D2 specimens on surface roughness wereconducted and a comparison took place with hard turning. To investigate the effect temperature increase on bothtechniques, the machined surface of workpieces is examinedusing optical and scanning electron microscopy SEM.Practical results shows the lower workpiece hardness andlower cutting conditions resulted in a better surface roughness. Finally results showed that in hard machining not only themachining parameters have an influence on the surfaceroughness but also the material hardness found effective factorin finishing process.

The effect of workpiece hardness and cutting parameters on temperature, surface roughness and tool wear in ultrasonic assisted turning

The effect of workpiece hardness and cutting parameters on temperature, surface roughness and tool wear in ultrasonic assisted turning

Experimental investigation into the effects of nozzle position, workpiece hardness, and tool type in MQL turning of AISI 1045 steel

ABSTRACTMinimum quantity lubrication (MQL) is a replacement for dry machining in which a minimum quantity of lubricant fluid is mixed up with compressed air and sprayed periodically on the machining area. In this research the effects of different parameters on the MQL turning of AISI 1045 steel have been investigated to evaluate the cutting force, surface roughness, and tool wear in comparison with the wet and dry machining. The research is aimed to study the effect of the MQL nozzle position, workpiece hardness and tool type on the output parameters. During MQL machining experiments, the nozzles were placed in three different arrangements relative to the tool to investigate the effect of the nozzle position. The effect of workpiece hardness and tool type were also studied experimentally for different lubrication conditions. The results indicated that the MQL system significantly increases the cutting efficiency in AISI 1045 steel machining. The experiments results have also confirmed a significant influence of the nozzle position, workpiece hardness, and tool type on the outputs. Machining with MQL is also beneficial to the environment and machine tool operator health as lubricant consumption during operation with MQL is 7-fold lower than in the conventional system.

Machinability Assessment through Experimental Investigation during Hard and Soft Turning of Hardened Steel

In this study, experimental investigations were carried out to assess the machinability of hardened AISI 4340 steel during hard (55 HRC) and soft turning (35 and 45 HRC) using TiC mixed alumina ceramic tools. Mathematical models, which can predict the machining performances, namely, chip-tool interface temperature, cutting forces and surface roughness were developed based on experimental observations. Effect of workpiece hardness and cutting parameters, namely, cutting speed, depth of cut and feed on different responses were analyzed by performing ANOVA technique. Experimental observations indicate higher cutting forces, higher chip-tool interface temperature and lower values of surface roughness for harder workpiece. Feed value has been observed to have more prominent effect on surface roughness. However, the average chip-tool interface temperature has been observed to get more influenced with cutting speed and depth of cut. On the other hand, cutting forces, especially radial component of force which was largest in magnitude amongst the tangential and feed cutting forces, has been observed to get more affected with depth of cut followed by feed value.

Hardness Effects on Abrasive Flow Machining

Abrasive flow machining (AFM) is a manufacturing technique that uses the flow of a pressurized abrasive media to remove workpiece material. In comparison with other polishing technique, AFM is very efficient, suitable for the finishing of complex inner surfaces. In this paper, the effect of workpiece hardness on the AFM process has been investigated. An experimental study was carried out on AISI D2 tool steel hardened to 31, 45 and 55 HRC. The specimens were cut by using wire electro discharge machining (WEDM) and then finished with AFM. The results show that the white layer formed during WEDM is successfully removed by AFM in a few cycles. Although the surface quality is improved by AFM for all hardness groups, the results show that harder materials have more surface improvement than the softer ones.

Effect of Workpiece Hardness on Surface Microgeometry when Hard Turning with Ceramic Inserts

Hard turning provides an alternative to grinding in some finishing operations. This paper deals with analysis of part surface finishing when turning hardened steel heat-treated on hardness of 46, 55 and 60 HRC with mixed oxide ceramic inserts. Average surface roughness Ra has been widely used in industry it is known that the single parameter Ra is inadequate to define the functionality of a surface. Two different surfaces with similar values of Ra can behave differently under loading conditions. The surface profile 2D and 3D parameters are assessed. The influence of workpiece hardness on surface roughness parameters and cutting force components is investigated. Results show that finish hard turning with mixed ceramic tool produces surface profile comparable to those produced by grinding.

Cryogenic Machining of Hard-To-Machine Material, <i>AISI 52100</i>: A Study of Chip Morphology and Comparison with Dry Machining

Cryogenic cooling is a new emerging cooling application in machining processes. Quantitative understanding of the effects of cryogenic cooling on the machining performance is important for continued applications. This study focuses on cryogenic machining of hard-to-machine material, AISI 52100, particularly with an analysis of cooling-induced chip morphology, chip hardness and the effect of workpiece hardness, etc., as these measures reflect the material`s thermo-mechanical behavior during the plastic deformation. AISI 52100 steel, with different initial hardness values, is selected as the work material for orthogonal cutting under dry and cryogenic cooling conditions, and the results are compared. The findings of this study show that cryogenic cooling affects the chip formation process, and the associated hardness produced on the machined surface.

Effects of Tool Geometry and Workpiece Hardness on Surface Roughness in Finish Hard Turning of AISI 440C

In this study, the effects of cutting tool geometry and workpiece hardness on surface roughness in finish hard turning of AISI 440C steel were experimental investigated. Four-factor (hardness, tool geometry, feed rate and cutting speed) two-level fractional experiments were conducted and analysis of variance (ANOVA) was performed. This study showed that the effects of workpiece hardness and tool geometry on surface roughness are statistically significant. Especially lower workpiece surface hardness and larger tool nose angle resulted in lower surface roughness because that the surface hardness influences the workpiece’s flow stress and the tool nose angle changes the contact area between the cutting tool and workpiece.

Machinability evaluation in hard turning of AISI 4340 steel with different cutting tools using statistical techniques

This paper is concerned with the continuous turning of AISI 4340 steels with hardness values in the range between 360 and 460 HV using cubic boron nitride, ceramic, and P10 grade carbide tools. The objective of this paper is to study the performance of these cutting tools and the effect of workpiece hardness on machinability responses. The samples were oil quenched and tempered at 250, 350, and 500 °C for 1 h in order to obtain different hardness values. Surface roughness, tool flank wear, maximum tool—chip interface temperature, and microhardness variations after machining are assessed. A Taguchi orthogonal array was used to guide the experiments. Cutting speed, feed rate, depth of cut, workpiece hardness, and tool types were varied in the experiments. A detailed statistical investigation was made by using analysis of variance, Tukey—Kramer comparison, and correlation tests. The best combination of cutting parameters for determining optimal conditions and the influence of each factor on the response were revealed and are discussed in detail.

Investigation of cutting conditions and cutting edge preparations for enhanced compressive subsurface residual stress in the hard turning of bearing steel

Residual stresses in the machined surface and the subsurface are affected by cutting tool, workpiece, tool/workpiece interface, and cutting parameters, such as feed rate, depth of cut and cutting speed. The prediction of residual stress profile in the machined surface is difficult due to the lack of proper material model to depict the material behavior and the complex interaction among the dominant factors. In this paper, the effects of workpiece hardness, tool geometry as well as cutting conditions on the residual stress distribution in the hard machined surface are investigated using a newly proposed hardness-based flow stress model employed in an elastic-viscoplastic FEM formulation. Special attention is paid to the effect of cutting edge preparation on the beneficial as well as the penetration depth of the residual stress in the machined surface. Simulation using different cutting edge preparations, namely sharp edge, small hone, large hone, chamfer and different combinations of hone plus chamfer, are conducted to obtain residual stress profile on the machined surface. Numerical results show an optimal combination of large hone edge + chamfer and aggressive feed rate help to increase compressive residual stress in both axial and circumferential directions.

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.

Effect of cutting edge geometry and workpiece hardness on surface generation in the finish hard turning of AISI 52100 steel

An experimental investigation was conducted to determine the effects of tool cutting edge geometry and workpiece hardness on the surface roughness and cutting forces in the finish hard turning of AISI 52100 steel. Cubic boron nitride inserts with various representative cutting edge preparations and through-hardened AISI 52100 steel bars were used as the cutting tools and workpiece material, respectively. This study shows that the effect of edge geometry on the surface roughness and cutting forces is statistically significant. Specifically, large edge hones result in higher average surface roughness values than small edge hones, due to increase in the extent of ploughing compared to shearing. The effect of the two-factor interaction of the edge geometry and workpiece hardness on the surface roughness is also found to be important. Additionally, large edge hones result in higher forces in the axial, radial, and tangential directions than small edge hones. It is also shown that the effect of workpiece hardness on the axial and radial components of force is significant, particularly for large edge hones.