Influence of Cutting Speed on Surface Plastic Deformation and White Layer Formation of FGH95

2013 ◽  
Vol 589-590 ◽  
pp. 70-75 ◽  
Author(s):  
Jin Du ◽  
Zhan Qiang Liu
Keyword(s):  
Plastic Deformation ◽  
Surface Integrity ◽  
White Layer ◽  
High Reliability ◽  
Cutting Speed ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Layer Formation ◽  
Machined Surface ◽  
White Layer Formation

The superalloy parts in the aeronautical field demand high reliability, which is largely related to surface integrity. Surface integrity generally includes three parameters, such as geometric parameter, mechanical parameter and metallurgical parameter. The paper presents the influence of cutting speed on surface plastic deformation and white layer formation through orthogonal milling of FGH95 superally material. The influence of cutting speed on grain refinement of machined surface is also investigated. It is found that cutting speed has significantly effect on the surface metallurgical characteristic microstructure. The increasing of cutting speed creates severer plastic deformation. Surface plastic shear strain increases with the increasing of cutting speed, while the depth of plastic deformation decreases on contrary. White layer thickness is increased with the increasing of cutting speed. Through statistical analysis for grains number, it can be drawn that the higher the cutting speed, the more serious grains refinement.

Plastic deformation of collector plates at electric motor repair

2020 ◽  
pp. 79-82
Author(s):  
D.YU. Belan ◽  
G.B. Toder ◽  
K.V. Averkov ◽  
YU.V. Titov
Keyword(s):  
Plastic Deformation ◽  
Electric Motor ◽  
Roughness Parameter ◽  
Surface Plastic Deformation ◽  
Analytical Dependence ◽  
Surface Plastic ◽  
Machined Surface ◽  
Tool Surface ◽  
Diamond Burnishing ◽  
Traction Electric Motor

A tool was developed for smoothing the plates of an electric motor collector. An analytical dependence of the roughness parameter of the machined surface on the force applied to the tool is obtained. Keywords traction electric motor, collector, diamond burnishing tool, surface-plastic deformation, repair, roughness. [email protected]

Using the Simplex Design Technique for Optimization of Modes of Burnishing with Ball Tools

2018 ◽  
Vol 284 ◽  
pp. 1210-1214
Author(s):  
A.V. Tyurin ◽  
N.Ya. Galimova ◽  
A.V. Belyaev
Keyword(s):  
Plastic Deformation ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Initial Surface ◽  
Design Technique ◽  
High Quality ◽  
Machined Surface ◽  
Damping Effect ◽  
Simplex Design ◽  
Variable Factor

It is advantageous to use the method of surface plastic deformation in order to get high-quality surfaces that meet increased requirements for strength and reliability. For efficient process of surface plastic deformation, it is required to define a set of conditions to provide minimum roughness of a machined surface. The paper addresses the problem of experimental search of optimal burnishing modes using the simplex design to minimize roughness of a machined surface. The significance of variable factor ranking was observed for this technique. A specific set of tests resulted in decrease in the initial surface roughness almost by 15 times in the specimens made of aluminum alloy after burnishing with the steel indenter. It was established that the surface quality was significantly affected by a new factor – angle of indenter contact with the machined surface, which had a damping effect on the machine-fixture-tool-workpiece system. The experiments showed that polished indenter balls significantly lowered the roughness grade of the machined surface under the same conditions.

Influence of Cutting Speed on Plastic Deformation in Machined Surface of FGH95 PM Superalloy

2011 ◽  
Vol 148-149 ◽  
pp. 163-168
Author(s):  
Jin Du ◽  
Zhan Qiang Liu
Keyword(s):  
Plastic Deformation ◽  
Cutting Speed ◽  
Machining Process ◽  
Surface Plastic ◽  
Machined Surface ◽  
Nickel Based Superalloy ◽  
Aerospace Applications ◽  
Plastic Shear Strain ◽  
Deformation Surface ◽  
Fgh95 Superalloy

FGH95 nickel-based superalloy is produced by powder metallurgy (PM) processing for aerospace applications. Due to lower thermal conductivity, work hardening tendency during machining, and intensive adhesion to the surface of the tooling under operation, machining of FGH95 alloy is a significant challenges. The FGH95 machining process will induce substantial amount of plastic deformation in the surface and subsurface of the workpiece. A theoretical model is developed to predict the plastic deformation in machined surface of FGH95 superalloy. Experimental results are also applied to analyze the influence of cutting speed on plastic deformation in machined surface of FGH95. It is found that cutting speed has significantly effect on the plastic deformation in the machined surface. The increasing the cutting speed creates severer plastic deformation. Surface plastic shear strain increases with the increases of cutting speed, while the depth of plastic deformation decreases contrary.

Study on the Effect of Grinding Parameters to the White Layer Formation in Grinding SKD-11 Hardened Steel

2008 ◽  
Vol 53-54 ◽  
pp. 279-284 ◽  
Author(s):  
Wei Wei Ming ◽  
Qing Long An ◽  
Ming Chen
Keyword(s):  
Rapid Heating ◽  
White Layer ◽  
Ground Surface ◽  
Hardened Steel ◽  
Manufacturing Processes ◽  
Layer Formation ◽  
Machined Surface ◽  
Variable Parameters ◽  
Die Steel ◽  
White Layer Formation

White layer formed in the machined surface has been observed in many manufacturing processes. However, grinding has been considered more sensitive to form white layer due to the characteristics with high temperature and rapid heating and quenching. As an effective process to the difficult-to-machining die steel, grinding is widely used in the finishing of die and mould components with high precision. So study on white layer formed in ground surface is significant to improve the product quality and life. In this paper, grinding experiments focus on SKD-11 hardened steel with variable parameters were conducted to study the white layer formation and the parameter optimization to develop the favorable white layer and restrict the thickness of the dark-etching layer and the hot-affective region.

Plastic deformation and grain refinement in surface layer induced by thermo-mechanical loads for hard milling process

2018 ◽  
Vol 233 (10) ◽  
pp. 2033-2046 ◽  
Author(s):  
BinXun Li ◽  
Song Zhang ◽  
Jing Zhang
Keyword(s):  
Plastic Deformation ◽  
Grain Refinement ◽  
Surface Integrity ◽  
White Layer ◽  
Milling Process ◽  
Experimental Result ◽  
Plastic Deformation Zone ◽  
Hard Milling ◽  
Machined Surface ◽  
Mechanical Loads

Microstructure alteration of machined surface induced by the coupled thermal and mechanical loads in the hard milling process has great influence on surface integrity. Hence, it affects the performances of the workpiece. The hard milling experiments of AISI H13 steel with different cutting speeds and feed rates were carried out and the microstructure evolution of machined surface was investigated by means of some advanced characterization methods. The experimental result indicates that plastically deformed layer was evident with three distinguishable zones, that is, unaffected zone, plastic deformation zone, and white layer zone. X-ray diffraction analysis revealed that no retained austenite is detected in the white layer. Numerous nano-sized equiaxed grains were induced by dynamic recrystallization (DRX), as a result of severe shear plastic deformation on the machined surface. As the cutting speed increases, the grain refinement becomes more obvious. However, the original cementite was greatly refined and well distributed compared with bulk material. A significant improvement in nano-hardness was witnessed in both for machined surface and subsurface. The grain refinement as well as well-dispersed cementite played a vital role in the improvement of nano-hardness. The varied depth of plastic deformation was observed with respect to change of cutting forces. It is the main source of mechanical load inducing plastic deformation with the assistance of material thermal softening. The present work can provide more visibility on the surface integrity along with the quality control of the workpiece.

Effects of Process Parameters on White Layer Formation and Morphology in Hard Turning of AISI52100 Steel

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Li Chen ◽  
Han Ding
Keyword(s):  
Heat Treatment ◽  
Residual Stresses ◽  
Hard Turning ◽  
White Layer ◽  
Cutting Speed ◽  
Layer Formation ◽  
Bulk Materials ◽  
Medium Temperature ◽  
White Layer Thickness ◽  
White Layer Formation

Hard turning is becoming increasingly considered by industry as a potential substitute for grinding. However, it is greatly hurdled by surface integrity problems such as tensile residual stress and white layer, which are generally found to have negative effects on the stress corrosion, wear resistance, and fatigue life of the machined parts. This paper investigates white layer formation and morphology in hard turning process using various process parameters, taking into account the effects of heat treatment which results in microstructure and hardness differences on bulk materials. Samples undergone three typical heat treatment processes are prepared and then machined using different cutting speeds and radial feed rates. Optical microscope, scanning electron microscope (SEM), and X-ray diffraction (XRD) are employed to analyze the microstructures of white layer and bulk materials after varies heat treatments and cutting processes. Through the studies, we find the existence of a cutting speed threshold, below which no white layer forms for both the low and medium-temperature tempering. The threshold value increases; however, the white layer thickness decreases under the same cutting conditions, for the low and medium-temperature tempering, respectively. Also, we find that the white layer thickness and the scattering of it along the cutting direction on the surface increases with cutting speed and radial feed rate. White layer with wavy morphology can be found in samples after quenching at high cutting speed. We first discover that the pitch of the white layer with wavy morphology is similar to the displacement of tool at the time a segment of the serrated chips forms. Also, the surface residual stresses of the samples are measured. Relationship between white layer and residual stresses is presented. Based on the relationship we reveal that high temperature is more dominant than volume expansion for white layer formation.

Experimental Study on the Impact of Cutting Speed on Surface Integrity of Ti-10V-2Fe-3Al

2014 ◽  
Vol 852 ◽  
pp. 476-480
Author(s):  
Hou Chuan Yang ◽  
Zhi Tong Chen ◽  
Ming Hua Chen
Keyword(s):  
Surface Integrity ◽  
White Layer ◽  
Aerospace Industry ◽  
Cutting Speed ◽  
Cnc Machining ◽  
Machined Surface ◽  
Workpiece Surface ◽  
Speed Increase ◽  
The Impact ◽  
Machined Surface Integrity

Titanium Alloy Ti-1023 is widely utilized in aerospace industry; the integrity of the parts machining surfaces is of critical importance for aerospace industry. Surface roughness, microstructure and microhardness variations were investigated on a CNC machining at different cutting speeds. Experiments results showed machined surface integrity of Ti-1023was sensitive to cutting speed. The roughness of machined surface raised with increase of the cutting speed from 40 m/min to 100 m/min, but decreased while the cutting speed increase from 100 m/min to 300 m/min. It can also draw the conclusion that no significant phase transformation, no obvious deformation and no white layer on subsurface microstructure can be observed. As for microhardness, it can also be seen that the machined workpiece surface was not seriously hardened, less than 35μm depth of work hardening at different cutting speed.

An Experimental Study on Subsurface Mechanical Behavior, Residual Stress, and Microstructure Induced by Process Dynamics in Machining

2004 ◽  
Author(s):  
A. W. Warren ◽  
Y. B. Guo
Keyword(s):  
Residual Stress ◽  
Strain Hardening ◽  
Surface Integrity ◽  
White Layer ◽  
Cutting Speed ◽  
Small Scale ◽  
Displacement Curve ◽  
Machined Surface ◽  
Microstructure Changes ◽  
Load Displacement

Surface integrity of machined components is critical for product performance in service. Process dynamic parameters, such as cutting speed and the changing contact condition between the tool flank face and machined surface, have a significant influence on surface integrity of a machined surface. Due to the very small scale of surface integrity factors on a machined surface, nanoindentation can be used to determine the surface/subsurface mechanical properties. However, the test data may be significantly influenced by machining induced residual stresses, strain hardening, and microstructure changes. The fundamental relationships between residual stress, microstructure, and nanohardness in the machined surface are yet to be understood. Further, it is not clear how to determine residual stress, at least its nature of tensile or compressive, from the nanoindentation data with the presence of complex residual stress state, strain hardening, and microstructure changes. This study focuses on the effects of cutting speed and machining system damping or rigidity (through varying tool flank wear) on subsurface mechanical state and the basic relationships between residual stress, white layer, and nanohardness. A series of nanoindentation tests were conducted to machined samples with distinct surface integrity by hard turning, grinding, and honing. It was found that white layer increases nanohardness and dark layer decreases nanohardness in subsurface, while strain hardening only slightly increases subsurface hardness. The research results indicate that subsurface residual stress can be qualitatively characterized by the load-displacement curve pattern and its parameters such as slope at initial loading, total depth, residual depth, and the ratio of residual depth to total depth. Residual stress would affect a load-displacement curve shape only at onset of yielding. Microstructure changes would make a significant difference on the characteristics of a load-displacement curve, while strain hardening exerts slight influence on the curve characteristics. In addition, the mechanism of residual stress on indentation depth was explained using a Mohr’s circle.

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