The influence of turning parameters on surface integrity of nickel alloy 625

Author(s):  
Daniel Loureiro ◽  
Anselmo E Diniz ◽  
Alexandre B Farina ◽  
Sérgio Delijaicov

Nickel-based alloys are used in industrial sectors where high mechanical strength and corrosion resistance are required at high temperatures. However, these alloys have low machinability as a consequence of inherent properties. Some of these properties such as high cold work hardening rate and low heat conductivity may cause damages to the machined surface. Among the nickel-based alloys, one that has good properties for oil exploration is alloy 625. As the components made of this alloy are frequently used in very rough environments, this study sought to evaluate the influence of tool geometry, cutting conditions (feed and cutting speed) and tool condition (fresh or worn) on the surface integrity of turned alloy 625 parts in order to discover turning practices for this alloy that result in minimal damage to the workpiece surface. A secondary aim was to evaluate how these input variables affected the life of the coated carbide tools used in the turning experiments with this alloy. The main conclusions are that (a) the surfaces produced with a fresh tool with positive geometry had compressive residual stresses, while those produced with negative tool geometry had tensile residual stresses and (b) when a worn tool was used all the surfaces produced had compressive residual stresses.

2010 ◽  
Vol 447-448 ◽  
pp. 816-820 ◽  
Author(s):  
Erween Abdul Rahim ◽  
Hiroyuki Sasahara

Surface integrity is particularly important for the aerospace industry components in order to permit longer service life and maximized its reliability. This present work compares the performance of palm oil and synthetic ester on surface roughness, surface defect, microhardness and subsurface deformation when high speed drilling of Ti-6Al-4V under MQL condition. The drilling tests were conducted with AlTiN coated carbide tool. The surface roughness decreased with increasing in cutting speed and thicker subsurface deformation was formed underneath the machined surface. Grooves, cavities, pit holes, microcracks and material smearing were the dominant surface damages thus deteriorated the machined surface. For both lubricants, the machined surface experienced from thermal softening and work hardening effect thus gave a variation in microhardness values. The results indicated the substantial benefit of MQL by palm oil on surface integrity.


2009 ◽  
Vol 83-86 ◽  
pp. 1059-1068 ◽  
Author(s):  
Armansyah Ginting ◽  
Mohammed Nouari ◽  
Nadhir Lebaal

In this paper, the surface integrity is studied when machining the aeronautical titanium alloys. Surface roughness, lay, defects, microhardness and microstructure alterations are studied. The result of surface roughness judges that the CVD-coated carbide fails to produce better Ra value than the uncoated. Lay is characterized by cutting speed and feed speed directions. Feed mark, tearing surface, chip layer formation as built up layer (BUL), and deposited microchip are the defects. Microhardness is altered down to 350 microns beneath the machined surface. The first 50 microns is the soft sub-surface caused by thermal softening in ageing process. Microstructure alteration is observed in this sub-surface. Down to 200 microns is the hard sub-surface caused by the cyclic internal work hardening and then it is gradually decreasing to the bulk material hardness. It is concluded that dry machining titanium alloy is possible using uncoated carbide with cutting condition limited to finish or semi-finish for minimizing surface integrity alteration.


1999 ◽  
Vol 122 (4) ◽  
pp. 620-631 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi

The effects of cutting conditions and tool wear on chip morphology and surface integrity during high speed machining of D2 tool steel (60–62 Hrc) are investigated experimentally and analytically in this paper. Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this investigation. The chips and the subsurface of the workpiece are examined using optical and scanning electron microscopy. Microhardness measurements are performed on the surface and subsurface of the workpiece. The X-ray diffraction technique is used to measure the residual stresses induced in the machined surface. The paper is divided into two parts. Part 1 presents the results obtained from the micrographical analysis of the chips and the surfaces produced. Part 2 deals with microhardness and residual stresses of the machined surface. The micrographical analysis of the chips produced shows that different mechanisms of chip formation exist depending on the magnitude of the cutting pressure and tool wear. Saw toothed chips are produced during the machining of D2 tool steel if the cutting pressure exceeds approximately 4000 MPa. The metallographic analysis of the surface produced illustrates the damaged surface region that contains geometrical defects and changes in the subsurface metallurgical structure. The types of surface damage are dependent on the cutting conditions, tool geometry and the magnitude of the wear lands. [S1087-1357(00)00104-0]


2012 ◽  
Author(s):  
Che Hassan Che Haron ◽  
Andanastuti Muchtar ◽  
Nik Faizu Nik Kundor

Projek ini dijalankan bertujuan untuk mengkaji kesan proses pengisaran terhadap keutuhan permukaan keluli perkakas D2. Dalam kajian ini, keluli perkakas kerja sejuk AISI D2 yang telah dikeraskan kepada 62 HRC dimesin menggunakan sisip karbida bersalut CVD boleh indeks yang dipegang oleh perkakas pengisaran hujung berdiameter 20 mm. Siri–siri ujian dijalankan dalam keadaan kering. Penilaian ke atas permukaan yang dimesin melibatkan kekasaran permukaan dan analisis mikrostruktur. Keputusan kajian menunjukkan bahawa tiada hubungan yang jelas di antara variasi kelajuan pemotongan dan suapan terhadap kekasaran permukaan. Umumnya, permukaan yang dihasilkan adalah sangat licin dengan nilai Ra berada dalam julat 0.10 μm – 0.43 μm dan analisis permukaan pada sampel–sampel ujikaji juga mendapati hampir tiada perubahan dapat dikesan pada mikrostruktur bahagian bawah permukaan yang dimesin. Walau bagaimanapun, pada kelajuan pemotongan tertinggi (160 m/min) dan suapan yang tinggi (0.02 mm/sisip), terdapat kesan termampat dan terherot pada mikrostruktur pada kedalaman yang sangat cetek iaitu lebih kurang 2.2 μm dari permukaan termesin. Kata kunci: Keutuhan permukaan, keluli perkakas terkeras, pengisaran hujung, mikrostruktur, perkakas karbida bersalut The effect of milling process on the surface integrity of newly machined surface of D2 tool steel is presented. The hardened AISI D2 (62 HRC) was machined under dry cutting conditions using a 20 mm diameter end–milling tool with indexable CVD coated carbide insert. Analyses revealed that the variation in cutting speeded and feed did not significantly affect the surface roughness of the machined surface. Generally, the surfaces produced are very smooth with Ra values in the range of 0.1 – 0.43 μm, and studies showed almost no microstructure alteration on the machined surfaces. However, at the highest cutting condition, i.e. a cutting speed of 160 m/min, and feed of 0.02 mm/tooth, some compression and distortion effects were detected on the microstructure at the very shallow depth of approximately 2.2 μm from the machined surface. Key words: Surface integrity, hardened tool steel, end-milling, microstructure, coated carbide tool


2014 ◽  
Vol 996 ◽  
pp. 658-663 ◽  
Author(s):  
Jose Carlos Outeiro ◽  
António Castanhola Batista ◽  
Maria Jose Marques

The major challenge of the Mg alloys has been their unsatisfactory corrosion resistance, which can be enhanced by improving the surface integrity. Cryogenic machining, where liquid nitrogen was used during machining, has been reported to improve the surface integrity of machined components, including compressive residual stresses. This paper analyses the influence of several cutting parameters, tool geometry and cryogenic conditions on the surface and subsurface residual stresses distribution.


2013 ◽  
Vol 698 ◽  
pp. 127-136 ◽  
Author(s):  
Kamel Moussaoui ◽  
Michel Mousseigne ◽  
Johanna Senatore ◽  
Pierre Lagarrigue ◽  
Yves Caumel

The present article addresses the influence of milling on the surface integrity of Ti-6Al-4V. Observation of the machined surface from a macroscopic perspective (naked eye) has highlighted anorange peelphenomenon. Under the machined surface no plastically deformed layer or lengthening of the grains were observed. As far as microhardness is concerned, a slightly softened zone was noted under the machined surface. Diffusion of vanadium from phase β to phase α also occurred but without resulting change to the microstructure. Measurement of microhardness and residual stresses showed that the finishing pass predominated over the roughing pass in terms of its influence on surface integrity. The response surface methodology was used in order to highlight those parameters influencing surface integrity. Its application and processing showed that the most influential factor is the nose radius for roughness and the cutting speed for residual stresses.


2021 ◽  
Vol 347 ◽  
pp. 00037
Author(s):  
Gary Styger ◽  
Rudolph F Laubscher

The surface integrity of a turned machined surface is an essential indicator of the fatigue and corrosion performance of a component. A critical descriptor of this property is the residual stress, both on the surface and subsurface of a part. However, experimental determination of vital surface integrity parameters such as surface roughness, hardness, affected microstructure, and residual stresses is costly, time consuming, and involves the destruction of the part. Therefore, prediction of these parameters, such as residual stress versus depth, would be of great value and could aid in the correct machining parameters (cutting speed, feed rate, edge tool radius, rake angle, coolant) for the desired part performance. A study was initiated to determine the influence of a worn tool and multiple cuts on a wide range of cutting speeds on residual stresses induced by machining an outside-turned bar of Ti6Al4V titanium alloy. Thus, a project was initiated to develop a non-linear finite element model to predict the residual stresses thus developed due to the machining manufacturing process.


2010 ◽  
Vol 447-448 ◽  
pp. 811-815 ◽  
Author(s):  
Erween Abdul Rahim ◽  
Hiroyuki Sasahara

Nickel-based superalloys remain the most widely used of all materials in aerospace industry, contributed over 50 % of the weight of a jet engine. In machining of any jet engine components, it is necessary to satisfy the surface quality or surface integrity requirements to facilitate high reliability components. In the present study, surface integrity of Inconel 718 was studied when drilling under different lubricants. The holes were drilled individually using indexable AlTiN coated carbide drill under minimum quantity of lubricant (MQL) conditions. The results demonstrated that the machining conditions and lubricants strongly influence the surface integrity. The surface roughness decreases with the increase in cutting speed and increases with the increase in feed rate. Microhardness profiles indicated that the subsurface deformation extends up to a 100 and 150 μm for palm oil and synthetic ester, respectively underneath the machined surface. Pit holes, cavities, grooves, microcracks and surface smearing were the dominant surface damages criteria for all cases.


2021 ◽  
Vol 5 (3) ◽  
pp. 70
Author(s):  
Alexandre Mondelin ◽  
Frédéric Valiorgue ◽  
Joël Rech ◽  
Michel Coret

This paper investigates the residual stresses induced by a longitudinal turning operation in 15-5PH martensitic stainless steel. An experimental investigation has quantified the sensitivity of residual stresses to cutting speed, feed, tool geometry and tool flank wear. In parallel, a 3D hybrid model, previously developed, has been applied to each case study. This modelling approach consists of replacing tooling and chipping by equivalent thermal and mechanical loadings. These equivalent loadings are moved onto the machined surface to compute the final residual stress state. It has shown that tool geometry and tool flank wear have a dominant effect on residual stresses compared to cutting speed and feed rate. However, cutting speed influences the intensity of the compressive peak, to some extent, whereas feed influences the affected depth. This work has also shown that the 3D hybrid model is able to predict residual stresses, as well as the sensitivity to cutting parameters, with reasonable agreement.


2014 ◽  
Vol 633-634 ◽  
pp. 574-578 ◽  
Author(s):  
Xia Ji ◽  
Alexander H. Shih ◽  
Manik Rajora ◽  
Ya Min Shao ◽  
Steven Y. Liang

Surface integrity, such as surface roughness and residual stress, is an aspect of surface quality on machined parts. Residual stress in the machined surface and subsurface is affected by materials, machining conditions, and tool geometry. These residual stresses could affect the service qualify and component life significantly. Residual stress can be determined by empirical or numerical experiments for selected configurations, even if both are expensive procedures. This paper presents a hybrid neural network that is trained using Simulated Annealing (SA) and Levenberg-Marquardt Algorithm (LM) in order to predict the values of residual stresses in cutting and radial direction after the MQL face turning process accurately. To verify the performance of the proposed approach, the predicted results are compared with the results obtained by training an ANN using SA and LM separately. The results have shown that the hybrid neural network outperforms SA and LM in predicting machining induced surface integrity that is critical to determine the fatigue life of the components.


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