Experiment Study of Adiabatic Shear Critical Conditions in Orthogonal Cutting of Fe-36Ni Invar Alloy

2011 ◽  
Vol 305 ◽  
pp. 198-201
Author(s):  
Guo He Li ◽  
Hou Jun Qi ◽  
Bing Yan

Orthogonal cutting experiments of Fe-36Ni invar alloy are performed. The change of chip morphology with cutting conditions are investigated through metallurgical observation, and the critical cutting speed of adiabatic shear for Fe-36Ni invar alloy at different cutting depths and rake angles are given. In addition, the characteristic of chip deformation before the occurrence of adiabatic shear is also analyzed. The results show that the critical cutting speed decreases with the increase of cutting depth and hardness, but increases with the increase of rake angle. The deformation coefficient tends to a constant value with the increase of cutting speed.

2011 ◽  
Vol 188 ◽  
pp. 110-115
Author(s):  
Guo He Li ◽  
Min Jie Wang

Orthogonal cutting experiments of Fe-36Ni invar alloy are performed to investigate the influence of cutting conditons on adiabtic shear, which occurs in the process of chip formation of many materials. It is found that the cutting speed, cutting depth and rake angle all have influence on adiabatic shear and there is a critical cutting speed at which the adiabatic shear appears. By metallurgical observation, the critical cutting speed under different cutting depth and rake angles are given. A model based on linear pertubation analysis is used to predict the adiabatic shear critical ctting conditions of Fe-36Ni invar alloy. The comparison of prediction results and that of expriments shows that this prediction model is available.


2011 ◽  
Vol 189-193 ◽  
pp. 3061-3065
Author(s):  
Guo He Li ◽  
Tie Li Qi ◽  
Yu Jun Cai ◽  
Hong Jun Wang

Orthogonal cutting experiments of hardened AISI1045 steel(45HRC) are performed to investigate the influence of cutting conditions on adiabatic shear which occurs in the process of chip formation of many materials. It is found that the cutting speed, cutting depth and rake angle all have influence on adiabatic shear and there is a critical cutting speed at which the adiabatic shear appears. By metallurgical observation, the critical cutting speed under different cutting depths and rake angles are given. A model based on linear pertubation analysis is used to predict the adiabatic shear critical cutting conditions of hardened AISI 1045 steel. The comparison of prediction results and that of expriments shows that this prediction model is valid.


2012 ◽  
Vol 500 ◽  
pp. 146-151 ◽  
Author(s):  
Ning Hou ◽  
Li Zhou ◽  
Shu Tao Huang ◽  
Li Fu Xu

In this paper, a finite element method was used to dynamically simulate the process of the edge defects formation during orthogonal cutting SiCp/Al composites. The influence of the cutting speed, cutting depth and rake angle of the PCD insert on the size of the edge defects have been investigated by using scanning electron. According to the simulated results, it can be provided that the cutting layer material has an effect on transfer stress and hinder the chip formation in the critical transition stage, and the critical transition point and distance are defined in this stage. The negative shear phenomenon is found when the chip transit to the edge defects in the flexure deformation stage, so the process of the chip formation is the basis of the edge defects formation. In addition, the relationship between the nucleation and propagation direction of the crack and the variation of the edge defect shape on the workpiece was investigated by theory, and it found that the negative shear angle formation is the primary cause of the edge defect formation. A mixed mode crack is found in the crack propagation stage. The sizes of edge defects were measured by the experiment and simulation, and the edge defect size decrease with the increasing of tool rake angle, while increase with increasing cutting depth and cutting speed.


2010 ◽  
Vol 139-141 ◽  
pp. 743-747
Author(s):  
Chun Zheng Duan ◽  
Hai Yang Yu ◽  
Min Jie Wang ◽  
Bing Yan ◽  
Yu Jun Cai

The development of chip morphology, critical cutting condition of adiabatic shear during serrated chip formation and cutting forces were observed and measured by high speed turning experiment for 30CrNi3MoV hardened steel. Results show that the cutting speed and rake angle are leading factors to influence chip morphology and cutting forces. With the increase of cutting speed, the continuous band chip transforms into serrated chip at a certain critical value. As the rake angle is changed from positive to negative, the critical cutting speed of adiabatic shear significantly decreases, the cutting forces abruptly reduces when the serrated chip forms. The results from predicting critical cutting speed using the critical cutting condition criterion of adiabatic shear in metal cutting process show that the leading reason of serrated chip formation is that the adiabatic shear fracture repeatedly occurs in the primary shear zone.


2014 ◽  
Vol 800-801 ◽  
pp. 571-575
Author(s):  
Guo He Li ◽  
Yu Jun Cai ◽  
Hou Jun Qi

Under the condition of cutting speed 10-300m/min, rake angle -10°、0°、10°and cutting depths 0.05mm、0.1mm and 0.2mm, the experiment study of adiabatic shear serrated chip and surface roughness are carried out. The influence of cutting condition on serrated chip is analyzed through the metallographic observation of obtained chip. By the measurement of finished surface, the influenc of cutting condition and adiabatic shear on surface roughness is also investigated. The rusults show that the reason lead to serrated chip in high speed cutting of Ti6Al4V is adiabatic shear, not the periodic fracture.The adiabatic shear serrated chip is easier appear and the degree of segment is more large under the condition of higher cutting speed, larger cutting depth and smaller rake angle. The surface roughness is smaller when the cutting speed is higher, cutting depth is larger, and rake angle is smaller.


Author(s):  
Shenfeng Wu ◽  
Xueping Zhang ◽  
C. Richard Liu

This paper proposes a thermo-mechanical orthogonal cutting finite element model (FEM) to investigate the variation of chip morphology from continuous chip to small and large saw-tooth chip. The corresponding experiments of hard turning AISI 52100 steel are conducted to validate the proposed FE model. Three one-factor simulation experiments are conducted to determine the evolution of chip morphology along feed rate, rake angle and cutting speed respectively. The chip morphology evolution is described by the variations of dimensional values, saw-tooth degree and chip segmental frequency. The research suggests that chip morphology transit from continuous to sawtooth chip with increasing the feed rate and cutting speed, and changing a positive rake angle to a negative rake angle. There exists a critical cutting speed at which the chip morphology transfers from continuous to saw-tooth chips. The saw-tooth chip segmental frequency decreases as the feed rate and negative rake angle value increase, but increases almost linearly with the cutting speed. The larger negative rake angle, the larger feed rate and high cutting speed dominate the sawtooth chip morphology while positive rake angle, small feed rate and low cutting speed determine continuous chip morphology.


2011 ◽  
Vol 383-390 ◽  
pp. 1915-1920
Author(s):  
Guo He Li ◽  
Bing Yan ◽  
Yu Jun Cai

Orthogonal cutting experiments of hardness AISI1045 steel( HRC45) are performed. The change of chip formation and cutting force with cutting conditions are investigated through metallurgical observation, and the critical cutting speed of adiabatic shear of AISI1045 steel at different cutting depths and rake angles are given. In addition, the saw-frequency and space length of serrated chip and the influence of serrated chip on cutting force are also studied. The critical cutting speed decreases with the increase of cutting depth, but increases with the increase of rake angle. The saw-frequency of serrated chip is found to be independent of the cutting depth, and increases with the increase of cutting speed and rake angle. The cutting force decreases with the increase of cutting speed and rake angle, but increases with the increase of cutting depth, and there isn’t a sudden change of cutting force at the onset of adiabatic shear.


2012 ◽  
Vol 516 ◽  
pp. 13-18 ◽  
Author(s):  
Ming Jun Chen ◽  
Gao Bo Xiao ◽  
Dan Li ◽  
Chun Ya Wu

The hierarchical approach of multi-scale modelling was adopted to study the nanometric cutting process of calcium fluoride. Then fly cutting experiments of CaF2 were performed to analyze the influence of cutting speed upon the surface roughness of CaF2. The results of FEM simulations show that larger negative rake angle and larger cutting edge radius lead to lower tensile stress in the cutting region. Tangential cutting force will first increase with an increase of negative rake angle and cutting edge radius, and then start to decrease with them. The tensile stress in the cutting region will increase with cutting depth at first, and then become stable when it reaches a certain extent. The specific cutting force increases rapidly with decrease of cutting depth, showing an obvious size effect. Within the range of cutting speeds adopted in the simulations, cutting speed has little influence on the tensile stress in the cutting region. And the results of fly cutting experiments show that cutting speed has little influence on the surface roughness of a machined surface under the cutting speeds adopted. This verifies the validity of the simulation result to some extent.


2012 ◽  
Vol 500 ◽  
pp. 230-235
Author(s):  
Shu Tao Huang ◽  
Li Zhou ◽  
Jin Lei Wang

Due to the superior mechanical and thermal properties of SiCp/Al composites, their poor machinability has been the main deterrent to their substitution for metal parts. Machining of SiCp/Al composites has been considerably difficult because the extremely abrasive nature of SiC reinforcements causes rapid tool wear. In this paper, an experiment was carried out to investigate the influence of the cutting speed, cutting depth and tool rake angle on cutting force during orthogonal machining of SiCp/Al composites. The results indicate that the cutting depth is one of the main cutting parameters that affect the cutting force, while the cutting speed and tool rake angle have no significant effects on the cutting force.


2012 ◽  
Vol 723 ◽  
pp. 99-104
Author(s):  
Guo He Li ◽  
Hou Jun Qi ◽  
Bing Yan

In this paper, some high speed cutting experiments of hardened 45 steel are carried out. The effects of cutting parameters on the width and space of adiabatic shear band, the frequency and degree of sawtooth are investigated by metallographic observation and theoretical calculation. The results show that the space of adiabatic shear band decreases with the increase of cutting speed and rake angle, but increases with the increase of cutting depth. The width of adiabatic shear band decreases with the increase of cutting speed and cutting depth, however, increases with the increase of rake angle. The frequency of sawtooth increases with the increases of cutting speed, decreases with the increase of rake angle, and has no obvious relationship with cutting depth. The degree of sawtooth increases with the increase of cutting speed and cutting depth, but decreases with the increase of rake angle.


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