Effect of Cutting Temperature on Phase Transformation in Cutting of NiTi Alloy

2020 ◽  
Author(s):  
Hao Yang ◽  
Katsuhiko Sakai ◽  
Hiroo Shizuka ◽  
Kunio Hayakawa ◽  
Tetsuo Nagare
Keyword(s):  
Phase Transformation ◽  
Phase State ◽  
Niti Alloy ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Cutting Process ◽  
Maximum Temperature ◽  
Machined Surface ◽  
Speed Condition ◽  
Work Material

Abstract In this study, the effect of cutting temperature on phase transformation in cutting of room temperature austenitic NiTi alloy was investigated by X-ray diffraction (XRD) and temperature measurements. Results from XRD reveals that after cutting process, the phase state of work material near the machined surface transformed from austenite to martensite at relatively low cutting speed conditions while the phase state of work material did not undergo any form of transformation at the highest cutting speed condition. Temperature measurement results measured with temperature indicating paint showed that the maximum temperature of work material near the machined surface in cutting process exceeded the Md temperature at the highest cutting speed condition. However, there was no phase transformation observed in cutting chips after cutting at all cutting speed conditions as the temperature of cutting chips was much higher than the Md temperature under all cutting speed conditions.

scholarly journals Effect of Cutting Speed on Shape Recovery of Work Material in Cutting Process of Super-Elastic NiTi Alloy

2021 ◽  
Vol 15 (1) ◽  
pp. 24-33
Author(s):  
Hao Yang ◽  
Katsuhiko Sakai ◽  
Hiroo Shizuka ◽  
Yuji Kurebayashi ◽  
Kunio Hayakawa ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Shape Recovery ◽  
Niti Alloy ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Cutting Process ◽  
Threshold Temperature ◽  
Work Material ◽  
Stable Part ◽  
Cutting Point

Increasing use of NiTi alloy products makes it very important to improve the cutting performance of this material. This study presents the effect of cutting speed on radial shape recovery of work material which is supposed to deteriorate the dimension accuracy in cutting process of super-elastic NiTi alloy. The shape recovery of work material was investigated at the beginning of cutting process, during the stable part of cutting process and after feed stops respectively utilizing a high-speed camera and a cutting force dynamometer in orthogonal cutting experiments at various cutting speeds. The mechanism of the shape recovery was investigated by analyzing the crystallization phase state of work material before and after cutting using XRD and measuring the temperature distributions on the end surface of work material during orthogonal cutting experiments using non-reversible temperature indicating paints correspondingly. Results show that at relatively low cutting speed, the temperature of work material near the cutting point did not exceed the threshold temperature of phase transformation, and thus work material generated obvious shape recovery throughout the whole cutting process due to the phase transformation. Increasing cutting speed could increase the temperature of work material; when cutting speed increased to 100 m/min, the temperature of work material near the cutting point exceeded the threshold temperature of phase transformation, thus work material did not generate obvious shape recovery because it could not undergo any form of phase transformation during the stable part of cutting process and after feed stops. Consequently, increasing cutting speed could be proposed as an approach to improve dimension accuracy by inhibiting shape recovery of work material in cutting process of NiTi alloy.

scholarly journals Cutting Zone Temperature Identification During Machining of Nickel Alloy Inconel 718

2017 ◽  
Vol 14 (2) ◽  
pp. 24-29
Author(s):  
Andrej Czán ◽  
Igor Daniš ◽  
Jozef Holubják ◽  
Lucia Zaušková ◽  
Tatiana Czánová ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Inconel 718 ◽  
Cutting Temperature ◽  
Cutting Edge ◽  
Cutting Process ◽  
Maximum Temperature ◽  
Machining Processes ◽  
Machined Surface ◽  
Cutting Zone

Abstract Quality of machined surface is affected by quality of cutting process. There are many parameters, which influence on the quality of the cutting process. The cutting temperature is one of most important parameters that influence the tool life and the quality of machined surfaces. Its identification and determination is key objective in specialized machining processes such as dry machining of hard-to-machine materials. It is well known that maximum temperature is obtained in the tool rake face at the vicinity of the cutting edge. A moderate level of cutting edge temperature and a low thermal shock reduce the tool wear phenomena, and a low temperature gradient in the machined sublayer reduces the risk of high tensile residual stresses. The thermocouple method was used to measure the temperature directly in the cutting zone. An original thermocouple was specially developed for measuring of temperature in the cutting zone, surface and subsurface layers of machined surface. This paper deals with identification of temperature and temperature gradient during dry peripheral milling of Inconel 718. The measurements were used to identification the temperature gradients and to reconstruct the thermal distribution in cutting zone with various cutting conditions.

Investigating Microstructural Changes and Phase Transformation During Slot Milling of Ti-6Al-4V in Dry, Flood Coolant and MQL Conditions

2019 ◽  
Author(s):  
Ashutosh Khatri ◽  
Muhammad P. Jahan ◽  
Xingbang Chen ◽  
Jianfeng Ma
Keyword(s):  
Phase Transformation ◽  
Cutting Speed ◽  
Thermal Softening ◽  
Phase Changes ◽  
Depth Of Cut ◽  
Dry Machining ◽  
Machined Surface ◽  
Microstructural Changes ◽  
Slot Milling ◽  
Β Phase

Abstract The objective of this study is to investigate the microstructural changes and phase transformation of chips and workpiece during slot milling on Ti-6Al-4V alloy in dry, flood coolant, and MQL conditions using uncoated carbide tools. The experiments were performed at varying feed rate and depth of cut with a fixed cutting speed of 50 m/min. The microstructures of the machined chips indicate that dry machining had the highest percentage of β-phase indicating higher phase transformation owing to higher tool temperature. The β-phase was found to be the least in MQL machining chips, which is very similar to the microstructural composition of un-machined surface. Although there were signs of phase transformation, there were very minimal changes in phases in the workpiece for all three machining conditions. In many cases, no change or slight decrease in β-phase was observed at the sub-surface, indicating thermal softening of the workpiece, especially in dry machining. The findings from this study confirm the fact that, high temperature close to beta transition temperature is generated during dry machining of titanium alloy, and most of heat is carried away by the chips resulting in phase transformation from alpha to beta phase in chips. However, no significant phase changes occurred into the microstructure of the workpiece in any condition, although minor thermal softening was found at the sub-surface of dry machined workpiece.

Effect of tool wear on chip formation during dry machining of Ti-6Al-4V alloy, part 1: Effect of gradual tool wear evolution

2015 ◽  
Vol 231 (9) ◽  
pp. 1559-1574 ◽  
Author(s):  
Shoujin Sun ◽  
Milan Brandt ◽  
Matthew S Dargusch
Keyword(s):  
Plastic Deformation ◽  
Tool Wear ◽  
Chip Formation ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Machined Surface ◽  
Segmented Chip ◽  
Gradual Development ◽  
Geometric Variables ◽  
On Chip

Geometric features of the segmented chip have been investigated along with the volume of material removed at a cutting speed at which tool wear is characterized by the gradual development of flank wear when cutting Ti-6Al-4V alloy. The chip geometric variables varied with an increase in the volume of material removed as the combined effect of change in tool’s geometry and increase in cutting temperature. Plastic deformation dimples were observed as periodical regions on the machined surface, a row on each undeformed surface and region on the top of the slipping surface of the segmented chip when cutting with new tool; these dimples on the undeformed surface and machined surface are elongated in the direction of chip flow. All these dimples became less with an increase in the volume of material removed and almost disappeared when the chip was removed with the worn tool at the end of its life. A model of segmented chip formation process has been proposed to satisfactorily explain the formation of the plastic deformation dimples on the undeformed surface and machined surface of the segmented chip produced with a new cutting tool and the transition of chip geometry with the evolution of tool wear.

Experiment of Temperature Field for High Speed Orthogonal Turning

2011 ◽  
Vol 117-119 ◽  
pp. 594-597 ◽  
Author(s):  
Mu Lan Wang ◽  
Yong Feng ◽  
Xiao Xia Li ◽  
Bao Sheng Wang
Keyword(s):  
Temperature Field ◽  
High Speed ◽  
Model Simulation ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Experimental System ◽  
Maximum Temperature ◽  
Fem Model ◽  
High Speed Cutting ◽  
Orthogonal Turning

An experimental system used for temperature measurement is designed by the K-type thermocouple thermometry to achieve a direct measurement of cutting temperature in high speed orthogonal turning. The general regularity of temperature distribution is concluded, and the corresponding influences of cutting speed and cutting depth on the maximum temperature value are discussed in detail. Experimental data and simulating results are comparative analyzed to demonstrate the feasibility and correctness of Finite Element Method (FEM) model simulation and analytical solution. The verified model of temperature field can be applied to develop an effective non-contact soft-sensing method for high speed cutting temperature.

2D FEM Estimate of Tool Wear in Hard Cutting Operation: Tool Wear and Simulation of Hard Cutting Process under Steady State

2009 ◽  
Vol 69-70 ◽  
pp. 306-310
Author(s):  
Fu Gang Yan ◽  
Cai Xu Yue ◽  
Xian Li Liu ◽  
Yu Fu Li ◽  
Shu Yi Ji
Keyword(s):  
Steady State ◽  
Tool Wear ◽  
Model Simulation ◽  
Cutting Temperature ◽  
Cutting Process ◽  
Workpiece Material ◽  
Machined Surface ◽  
Fem Model ◽  
Fem Method ◽  
Hard Cutting

Tool wear plays an important role in cutting process research. It affects the quality of machined surface and cutting parameter to a great extent, such as cutting force, cutting temperature and cutting quiver. In order to predict tool wear in hard cutting process by using FEM method, the character of tool wear during cutting process is presented firstly, and Usui’s tool wear rate model is introduced. Then the FEM model for steady state cutting process using Abaqus is established. FEM model describes the workpiece material characteristic accurately for the process of PCBN tool cutting GCr15 by adoptiving Johnson-Cook constitutive model. Simulation results of steady cutting process offer foundation to simulate tool wear.

Real-Time Monitoring System of Cutting Process Based on Cutting Temperature

2008 ◽  
Vol 392-394 ◽  
pp. 946-950
Author(s):  
Yan Ming Quan ◽  
Jing Zhao ◽  
Y.S. Le
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Cutting Temperature ◽  
Current Collector ◽  
Cutting Process ◽  
Real Time Monitoring ◽  
Machined Surface ◽  
Tool Performance ◽  
Electrical Brush ◽  
Natural Thermocouple

Cutting temperature measurement and its variety tendency can reflect cutting tool performance and machined surface quality directly. By means of a mercury current collector or an electrical brush device the online measurement of thermoelectric potential of tool-workpiece natural thermocouple in milling is obtained, based on which a new cutting process real-time monitoring system is developed. The system takes the average cutting temperature in tool-workpiece interface as the monitoring target and the rotation rate of machine spindle as the adjustment object, which leaves out onerous and complex modeling and makes the monitoring and adjustment objective, direct and effective.

Study of Cutting Speed Variation in the Ultrasonic Assisted Drilling of Carbon Fibre Composites

2014 ◽  
Author(s):  
Aniruddha Gupta ◽  
Stuart Barnes ◽  
Iain McEwen ◽  
Nadia Kourra ◽  
Mark A. Williams
Keyword(s):  
Cutting Temperature ◽  
Cutting Speed ◽  
Hole Drilling ◽  
Machining Parameters ◽  
Machined Surface ◽  
Internal Damage ◽  
Significant Difference ◽  
Ultrasonic Assisted ◽  
Carbon Fibre Composites ◽  
Cutting Speeds

Ultrasonic assisted drilling (UAD) has been proven effective for the thrust force reduction as compared to conventional drilling (CD) for same machining parameters. The following research was focused on the examination of exit delamination, machined surface and cutting temperature measurement in UAD and a comparison to that in CD at the cutting speeds of 0.942 m/min, 9.42 m/min, 94.2 m/min and 282.6 m/min at a constant feed rate of 0.05 mm/rev in the through-hole drilling of CFRP material. X-Ray computed tomography (CT) was used to identify the exit delamination, internal damage, circularity and center deviation in CD and UAD. A maximum of 82.8% reduction in the center deviation and 33.2% reduction in circularity of the holes were found when drilled in UAD as compared to those in CD. Furthermore, the cutting temperature in the drilling of CFRP has been measured and compared for both the cases of CD and UAD. Ultrasonic assistance produced 10°C higher cutting temperature than that in CD at the cutting speed of 282.6 m/min while at lower cutting speeds (0.942 m/min and 9.42 m/min), the cutting temperatures with and without ultrasonic assistance did not have a significant difference (2°C and 4°C respectively).

Study on Effect of Ultrasonic Vibration in Machining of Alumina Ceramic

2012 ◽  
Vol 516 ◽  
pp. 311-316 ◽  
Author(s):  
Kyung Hee Park ◽  
Kyeong Tae Kim ◽  
Yun Hyuck Hong ◽  
Hon Jong Choi ◽  
Young Jae Choi
Keyword(s):  
Surface Roughness ◽  
Tool Wear ◽  
Ultrasonic Vibration ◽  
Cutting Forces ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Ultrasonic Machining ◽  
Machining Performance ◽  
Machined Surface ◽  
Combination Technique

Ultrasonic machining can be applied for the machining of difficult-to-cut materials using ultrasonical oscillation in an axial direction on top of tool rotation, which can cause reduction of cutting temperature and tool wear. In this study, the experiments were performed on a DMG ULTRASONIC 20 linear machine tool using diamond tools in both conventional and ultrasonic vibration assisted machining. The machining performance was evaluated and compared for both cases in terms of cutting forces, machined surface roughness and tool wear. And the combination technique of 3D surface topography measurement and image processing was applied for the tool wear progress. Overall, the experimental results showed that ultrasonic machining had less tool wear and lower cutting forces at low cutting speed compared to conventional machining. Also surface roughness was slightly lower in ultrasonic machining than that without ultrasonic vibration.

Evidence of Phase Dependent Tool Wear in Ti-6Al-4V Turning Experiments Using PCD and Carbide Inserts

2012 ◽  
Author(s):  
David J. Schrock ◽  
Patrick Kwon
Keyword(s):  
Phase Transformation ◽  
Tool Wear ◽  
Cutting Speed ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Rake Face ◽  
Work Material ◽  
Significant Difference ◽  
Pcd Tools ◽  
Cutting Speeds

This paper presents evidence of phase transformation in turning titanium work material and discusses its impact on tool wear. Tool wear of polycrystalline diamond inserts was studied in turning experiments on Ti-6Al-4V. Confocal laser scanning microscopy was conducted to analyze the rake face of the turning inserts. At cutting speeds of 61m/min, the rake face exhibited scalloped-shaped, fractured, uneven, and rough wear. This is characteristic of attrition wear. At cutting speeds of 122m/min, wear was smooth and even in nature, which is a typical characteristic of diffusion/dissolution wear. At a cutting speed of 91m/min, the wear was a combination of those observed at speeds of 61m/m and 122m/m. A comparison of the wear on the PCD tools to that of WC-6Co from earlier work is also discussed. A significant difference in wear existed between the two different cutting tool materials at the low cutting speed. This difference in wear was linked to a transition from alpha to beta phase in the titanium work material. Temperature estimates on the rake face of the tool previously extracted from FEM support the possibility of phase transformation at the cutting data tested.

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