Investigation on Machined Surface Quality During Cutting of GH4169 Under High-Pressure Cooling

2020 ◽  
Vol 12 (7) ◽  
pp. 994-1003
Author(s):  
Ming-Yang Wu ◽  
Wei-Xu Chu ◽  
Ke-Ke Liu ◽  
Shu-Jie Wu ◽  
Yao-Nan Cheng
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
High Pressure ◽  
Tensile Stress ◽  
Surface Quality ◽  
Work Hardening ◽  
Surface Plastic ◽  
Residual Tensile Stress ◽  
Machined Surface ◽  
Machined Surface Quality

The aerospace component material GH4169 has low thermal conductivity and poor machinability, resulting in difficulty to guarantee good surface quality after conventional cutting. High-pressure cooling assisted machining technology can effectively improve the problem. In order to study the effect of high-pressure cooling assisted processing technology on the machined surface quality of GH4169, in this paper, Deform-3D was first used to construct a thermo-mechanical coupling finite element model for turning GH4169 under high-pressure cooling conditions, to analyze the turning temperature and surface residual stress. Then, analysis was carried out on the residual stress, work hardening behavior, and metamorphic layer of the GH4169 machined surface, in combination with the turning experiment. The results show that, under the conditions of little feeding and highspeed cutting, the GH4169 turning surface generates residual tensile stress along with both the feeding and turning directions. Moreover, the residual tensile stress gradually turns into the residual compressive stress along the depth direction. The application of high-pressure coolant can reduce the residual tensile stress of the machined surface. As the cooling pressure increases, the residual tensile stress of the machined surface decreases. The coupling effect between thermal deformation and plastic deformation when turning GH4169 can cause the work hardening of the surface, and the hardening degree decreases with the increase of cooling pressure. The high-pressure cooling assisted machining technology can effectively reduce surface plastic deformation, and promote the lessening of grain refinement degree of the material surface, thereby reducing the thickness of the metamorphic layer.

Analysis of Surface Morphology in Work Hardening of High-Speed Milling Based on Dislocation Theory

2013 ◽  
Vol 373-375 ◽  
pp. 2015-2018
Author(s):  
Wen Jie Yang ◽  
Su Yu Wang ◽  
Yuan Chao Du ◽  
Lin Lin Ma
Keyword(s):  
Surface Quality ◽  
Work Hardening ◽  
High Speed ◽  
Lattice Distortion ◽  
Dislocation Theory ◽  
Machined Surface ◽  
High Speed Milling ◽  
Forming Mechanism ◽  
Machined Surface Quality ◽  
Micro Morphology

Work hardening is an important index for the evaluation of the machined surface quality in high-speed milling. The morphology of work hardening can be visually observed by the metallographic pictures of high-speed milling gained from the scanning electron microscope which includes the lattice distortion and cracks etc. Forming mechanism of lattice distortion and micro crack of micro morphology under the workpiece surface is analyzed according to the dislocation theory; meanwhile, the effects on surface quality of the microstructure of the work hardening layer are discussed, which have important guiding significances on improving the surface quality and prolonging the service life of the parts.

scholarly journals Atomistic Simulation Study of Nanoparticle Effect on Nano-Cutting Mechanisms of Single-Crystalline Materials

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 265 ◽  
Author(s):  
Pengyue Zhao ◽  
Qi Zhang ◽  
Yongbo Guo ◽  
Huan Liu ◽  
Zongquan Deng
Keyword(s):  
Plastic Deformation ◽  
Surface Quality ◽  
Cutting Tool ◽  
Deformation Mechanisms ◽  
Relative Depth ◽  
Machined Surface ◽  
Workpiece Surface ◽  
Single Crystalline ◽  
Machined Surface Quality ◽  
Cutting Mechanisms

Nanoparticle (NP), as a kind of hard-to-machine component in nanofabrication processes, dramatically affects the machined surface quality in nano-cutting. However, the surface/subsurface generation and the plastic deformation mechanisms of the workpiece still remain elusive. Here, the nano-cutting of a single-crystalline copper workpiece with a single spherical embedded nanoparticle is explored using molecular dynamics (MD) simulations. Four kinds of surface/subsurface cases of nanoparticle configuration are revealed, including being removed from the workpiece surface, moving as a part of the cutting tool, being pressed into the workpiece surface, and not interacting with the cutting tool, corresponding to four kinds of relative depth ranges between the center of the nanoparticle and the cutting tool. Significantly different plastic deformation mechanisms and machined surface qualities of the machined workpiece are also observed, suggesting that the machined surface quality could be improved by adjusting the cutting depth, which results in a change of the relative depth. In addition, the nanoparticle also significantly affects the processing forces in nano-cutting, especially when the cutting tool strongly interacts with the nanoparticle edge.

Finite Element Simulation and Experiment on Residual Stress in Turing 45# Steel with Complex Groove Tools

2014 ◽  
Vol 800-801 ◽  
pp. 305-310
Author(s):  
Yong Chun Zheng ◽  
Er Liang Liu ◽  
Jiao Li ◽  
Hong Yan Ju ◽  
Li Guo Zhao
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Tensile Stress ◽  
Cutting Force ◽  
Finite Element Simulation ◽  
Cutting Temperature ◽  
Residual Tensile Stress ◽  
Machined Surface ◽  
Coated Tools ◽  
Element Simulation

The research focused on the finite element simulation of the surface residual stress and took an experiment to get cutting temperature and cutting force by changing different groove and coated tools. Then it analyzed the influence of cutting and tool parameters on cutting force and temperature. Finally, the results reached a conclusion about the way that the tools with different groove and coating influenced the residual stress. The coated tools reduced the residual tensile stress in the machined surface. The axial and tangential residual stress was tensile stress and the tangential residual stress was larger than the axial in machining.

INVESTIGATION OF THE PROCESS OF RESTORATION OF DAMAGED PIPELINE SURFACES BY THE METHOD OF SURFACE RIVETING

2021 ◽  
pp. 126-132
Author(s):  
О.В. Уразов ◽  
А.Д. Данилов
Keyword(s):  
Residual Stress ◽  
Work Hardening ◽  
Experimental Studies ◽  
Surface Plastic Deformation ◽  
Numerical Control ◽  
Surface Plastic ◽  
Machined Surface ◽  
Surface Work ◽  
Stress Components ◽  
Industrial Unit

Представлены результаты экспериментальных исследований процесса восстановления поврежденных поверхностей трубопроводов различных диаметров методом поверхностного наклепа, реализующего явление поверхностного пластического деформирования, приводящее к изменению распределения напряжений по толщине, выполнено обоснование оптимальных режимов его проведения . При этом было осуществлено численное моделирование процесса накатки, определены оптимальные значения следующих параметров: глубины и силы ППД, скорости ППД, подачи ролика, формы рабочей поверхности используемого ролика. При анализе были учтены следующие физико-механические характеристики: глубина наклепа, величина остаточных напряжений, глубина распределения остаточных напряжений, время обкатки, нагрузка на ролик. Доказано очевидное преимущество роликов большего радиуса профиля - они позволяют обеспечить необходимое изменение шероховатости обрабатываемой поверхности при обкатке с большей подачей, что приводит к снижению времени технологического процесса. При этом в принятом диапазоне параметров режимов обкатки (нагрузка 2500÷3000Н, глубина вдавливания 0.04÷0.06мм) величины компонентов остаточных напряжений оказались практически идентичными для исследованных режимов всех рассмотренных роликов. Полученные результаты были положены в основу технологии восстановительного ремонта трубопроводов различного диаметра без остановки производственного процесса на Нововоронежской АЭС и создана промышленная установка с числовым программным управлением для реализации данной технологии Here we present the results of experimental studies of the process of restoration of damaged surfaces of pipelines of various diameters by the method of surface work hardening, which implements the phenomenon of surface plastic deformation, leading to a change in the distribution of stresses along the thickness. At the same time, we carried out a numerical simulation of the knurling process, we determined the optimal values of the following parameters: the depth and strength of the SPD, the speed of the SPD, the feed of the roller, the shape of the working surface of the roller used. The analysis took into account the following physical and mechanical characteristics: work hardening depth, residual stress value, residual stress distribution depth, running time, roller load. We proved the obvious advantage of rollers with a larger profile radius - they allow one to provide the necessary change in the roughness of the machined surface during rolling with a higher feed, which leads to a decrease in the time of the technological process. In this case, in the accepted range of parameters of the running modes (load 2500-3000N, indentation depth 0.04-0.06 mm), the values of the residual stress components turned out to be almost identical for the considered modes for all the considered rollers. We used the results as the basis for the technology of restorative repair of pipelines of various diameters without stopping the production process at the Novovoronezh NPP and an industrial unit with numerical control was created to implement this technology

scholarly journals Molecular Dynamics Investigation of Residual Stress and Surface Roughness of Cerium under Diamond Cutting

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 386 ◽  
Author(s):  
Yao Li ◽  
Maobing Shuai ◽  
Junjie Zhang ◽  
Haibing Zheng ◽  
Tao Sun ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Residual Stress ◽  
Surface Roughness ◽  
Surface Quality ◽  
Depth Of Cut ◽  
Formation Mechanisms ◽  
Machining Parameters ◽  
Diamond Cutting ◽  
Machined Surface ◽  
Machined Surface Quality

Machined surface quality in terms of residual stress and surface roughness has an important influence on the performance of devices and components. In the present work, we elucidate the formation mechanisms of residual stress and surface roughness of single crystalline cerium under ultraprecision diamond cutting by means of molecular dynamics simulations. Influences of machining parameters, such as the rake angle of a cutting tool, depth of cut, and crystal orientation of the workpiece on the machined surface quality were also investigated. Simulation results revealed that dislocation activity and lattice distortion are the two parallel factors that govern the formation of both residual stress and surface roughness. It was found that both distributions of residual stress and surface roughness of machined surface are significantly affected by machining parameters. The optimum machining parameters for achieving high machined surface quality of cerium by diamond cutting are revealed.

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]

scholarly journals The Comparative Study on Cutting Performance of Different-Structure Milling Cutters in Machining CFRP

2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu
Keyword(s):  
Carbon Fiber ◽  
Cutting Force ◽  
Surface Quality ◽  
Cutting Edge ◽  
Cutting Performance ◽  
Machining Process ◽  
Carbon Fiber Composites ◽  
Machined Surface ◽  
Milling Cutter ◽  
Machined Surface Quality

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.

Research on Grinding Force of Zirconia Internal Grinding with Resin Bond Diamond Wheel

2016 ◽  
Vol 1136 ◽  
pp. 30-35
Author(s):  
He Wang ◽  
Ke Zhang ◽  
Yu Hou Wu ◽  
Hong Song
Keyword(s):  
Grain Size ◽  
Surface Quality ◽  
Diamond Wheel ◽  
Grinding Force ◽  
Wheel Speed ◽  
Zirconia Ceramic ◽  
Machined Surface ◽  
Research Results ◽  
Internal Grinding ◽  
Machined Surface Quality

The zirconia parts are limited by machined surface quality. The grinding force is one of the most important parameters of grinding and has effects on surface quality. The MK2710 grinder and resin bond diamond wheels were used in zirconia grinding. The grinding force was obtained by Kistler dynamometer. The paper focused on wheel speed and grain size on grinding force, and examined the surface by SEM. The research results indicated that decreasing the grain size, the grinding force increased and the surface quality improved, and increasing wheel speed could decrease grinding force to improve grinding surface quality. The results can improve zirconia ceramic parts surface quality and promote application.

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