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.

Effects of Sequential Cuts on White Layer Formation and Retained Austenite Content in Hard Turning of AISI52100 Steel

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Xiao-Ming Zhang ◽  
Xin-Da Huang ◽  
Li Chen ◽  
Jürgen Leopold ◽  
Han Ding
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Retained Austenite ◽  
Hard Turning ◽  
White Layer ◽  
Layer Formation ◽  
White Layer Thickness ◽  
Austenite Content ◽  
Sequential Cuts ◽  
White Layer Formation

This technical brief is the extension of our previous work developed by Zhang et al. (2016, “Effects of Process Parameters on White Layer Formation and Morphology in Hard Turning of AISI52100 Steel,” ASME J. Manuf. Sci. Eng., 138(7), p. 074502). We investigated the effects of sequential cuts on microstructure alteration in hard turning of AISI52100 steel. Samples undergone five sequential cuts are prepared with different radial feed rates and cutting speeds. Optical microscope and X-ray diffraction (XRD) are employed to analyze the microstructures of white layer and bulk materials after sequential cutting processes. Through the studies we first find out the increasing of white layer thickness in the sequential cuts. This trend in sequential cuts does work for different process parameters, belonging to the usually used ones in hard turning of AISI52100 steel. In addition, we find that the white layer thickness increases with the increasing of cutting speed, as recorded in the literature. To reveal the mechanism of white layer formation, XRD measurements of white layers generated in the sequential cuts are made. As a result retained austenite in white layers is identified, which states that the thermally driven phase transformations dominate the white layer formation, rather than the severe plastic deformation in cuts. Furthermore, retained austenite contents in sequential cuts with different process parameters are discussed. While using a smaller radial feed rate, the greater retained austenite content found in experiments is attributed to the generated compressive surface residual stresses, which possibly restricts the martensitic transformation.

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.

Analysis of Surface Integrity for DIN 100Cr6 Steel Conical Bearing Rings after Hard Turning

2011 ◽  
Vol 223 ◽  
pp. 473-482 ◽  
Author(s):  
Sergio Delijaicov ◽  
Carlos Eddy Valdez Salazar ◽  
Éd Claudio Bordinassi ◽  
Linilsson Rodrigues Padovese
Keyword(s):  
Tool Wear ◽  
Residual Stresses ◽  
Hard Turning ◽  
White Layer ◽  
Cutting Speed ◽  
Hole Drilling ◽  
Machining Parameters ◽  
Hole Drilling Method ◽  
Conical Bearing ◽  
Bearing Rings

This work studies the influence of machining parameters, such as cutting speed and forces, feed rate, cutting depth, and tool flank wear, on the generation of surface residual stresses in DIN 100Cr6 steel conical bearing rings submitted to a hard turning process. A complete factorial planning was used to perform the tests and projected measurement. Cutting forces were measured by a piezoelectric dynamometer and residual stresses were determined by the hole-drilling method using strain gage. Results showed that after 2000 m of tool machining, phase transformations had been observed on sample surfaces, with white layer formation, and deeper, a dark layer whose thickness varied depending on the severity level of turning and the tool wear (in machined distance). Increase in tool wear generated minor values of compressive residual stresses and the surface roughness presented almost the same values in all experiments, except when the bigger parameters were used.

Effect of Alloying, Heat Treatment and Carbon Content on White Layer Formation in Machining of Steels

2005 ◽  
Author(s):  
Sangil Han ◽  
Shreyes N. Melkote
Keyword(s):  
Heat Treatment ◽  
Carbon Content ◽  
White Layer ◽  
Orthogonal Cutting ◽  
Layer Formation ◽  
Aisi 52100 ◽  
Aisi 1045 ◽  
White Layer Formation ◽  
Effect Of Alloying ◽  
Aisi 4340

This paper describes an experimental investigation of the role of alloying, carbon content, and heat treatment on white layer formation in machining of steels. This is carried out by machining steels that differ in alloying, heat treatment and carbon content, via orthogonal cutting tests performed with low CBN content tools. The thickness of white layer produced in AISI 1045 and AISI 4340 annealed steels are compared to determine the effect of alloying on white layer formation. The effect of heat treatment on white layer formation is investigated by machining annealed and hardened AISI 4340 steels. The effect of carbon content on white layer formation is investigated by cutting AISI 52100 and AISI 4340 steels of the same hardness (53 HRC). Since 52100 steel has almost twice the amount of carbon and less number of alloying elements than AISI 4340 steel, an approximate understanding of the effect of carbon content on white layer formation can be inferred. The results of the study show that alloying, heat treatment, and carbon content influence white layer formation. The possible roles of the maximum workpiece surface temperature, effective plastic strain and stress on white layer formation in the different steels are also analyzed via finite element simulations performed in a commercially available code.

Cutting temperatures during hard turning—Measurements and effects on white layer formation in AISI 52100

2014 ◽  
Vol 214 (6) ◽  
pp. 1293-1300 ◽  
Author(s):  
S.B. Hosseini ◽  
T. Beno ◽  
U. Klement ◽  
J. Kaminski ◽  
K. Ryttberg
Keyword(s):  
Hard Turning ◽  
White Layer ◽  
Layer Formation ◽  
Aisi 52100 ◽  
White Layer Formation
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