Investigation on Residual Stress and Flank Wear of Tool Insert in Hard Turning of Chrome Plated EN24 Substrate

Author(s):  
K.N. Mohandas ◽  
C.S. Ramesh ◽  
Eshwara Prasad Koorapati ◽  
N. Balashanmugam

In the present investigation the hard chrome plated surfaces were hard turned using PcBN cutting inserts. The results of the experiment showed that the hard turning can be applied for the finish machining of chrome plated surfaces. The influence of hard turning was observed when it was tested for residual stress distribution. The results disclosed that the chrome plating technhique has induced the compressive residual stress of -355.9MPa in the workpieces. These compressive residual stresses increased to a value of -723.3MPa after hard turning the chrome plated surfaces. But with worn out insert a tensile residual stress of 228.1MPa was observed in the workpiece. The results also revealed the variation of flank wear on the tool with different cutting inserts. The conclusions was drawn on the hard turning of hard chrome plated by adopting proper cutting conditions to replace the grinding operation by hard turning operation.

Author(s):  
Masahito Mochizuki ◽  
Yoshiki Mikami

The effect of transformation-induced microscopic residual stress on fatigue crack propagation behaviour of ferrite-martensite lamellar steel was discussed. Fatigue tests of prestrained and non-prestrained specimens were performed. Inflections and branches at ferrite-martensite boundaries were observed in the non-prestrained specimens. On the other hand, less inflections and branches were found in the prestrained specimens. The experimental results showed that the transformation induced microscopic residual stress has influence on the fatigue crack propagation behaviour. To estimate the microscopic residual stress distribution, a numerical simulation of microscopic residual stress induced by martensitic transformation was performed. The simulation showed that compressive residual stress was generated in martensite layer, and the result agree with the experimental result that inflections and branches were observed at ferrite-martensite boundaries. In addition, the change in the microscopic residual stress distribution by prestraining was also calculated to show the compressive residual stress changed to tensile by prestraining. This also agree with the experimental result of the observation of fatigue crack path.


Author(s):  
Balaji Sadasivam ◽  
Alpay Hizal ◽  
Dwayne Arola

Recent advances in abrasive waterjet (AWJ) technology have resulted in new processes for surface treatment that are capable of introducing compressive residual stresses with simultaneous changes in the surface texture. While the surface residual stress resulting from AWJ peening has been examined, the subsurface residual stress field resulting from this process has not been evaluated. In the present investigation, the subsurface residual stress distribution resulting from AWJ peening of Ti6Al4V and ASTM A228 steel were studied. Treatments were conducted with the targets subjected to an elastic prestress ranging from 0 to 75% of the substrate yield strength. The surface residual stress ranged from 680 to 1487 MPa for Ti6Al4V and 720 to 1554 MPa for ASTM A228 steel; the depth ranged from 265 to 370 μm for Ti6Al4V and 550 to 680 μm for ASTM A228 steel. Results showed that elastic prestress may be used to increase the surface residual stress in AWJ peened components by up to 100%.


Author(s):  
Mithun K. Dey ◽  
Dave Kim ◽  
Hua Tan

Abstract Residual Stress distribution and parametric influence of friction are studied for the split sleeve cold expanded holes in Al 2024 T351 alloy, by developing a three-dimensional finite element model of the process. Fastener holes in the alloy are necessary for the manufacturing process, but they create a potential area for stress concentration, which eventually leads to fatigue under cyclic loading. Beneficial compressive residual stress distribution as a result of the split sleeve cold expansion process provides retardation against crack initiation and propagation at the critical zones near hole edges. In this parametric study, the influence of friction between contact surfaces of the split sleeve and mandrel is numerically investigated. Hole reaming process after split sleeve cold expansion is often not discussed. Without this post-processing procedure, split sleeve cold expansion is incomplete in practice, and its purpose of providing better fatigue performance is invalidated. This study presents results and an overview of the significance of friction with the consideration of the postprocessing of split sleeve cold expansion. The numerical results show that with increasing friction coefficient, compressive residual stress reduces significantly at the mandrel entry side, which makes the hole edge more vulnerable to fatigue. The different aspects of finite element modeling approaches are also discussed to present the accuracy of the prediction. Experimental residual stress observation or visual validation is expensive and time-consuming. So better numerical prediction with the transparency of the analysis design can provide critical information on the process.


2014 ◽  
Vol 783-786 ◽  
pp. 2316-2321
Author(s):  
Hiroshi Kawakami ◽  
Akiyoshi Kondo ◽  
Muneharu Kutsuna ◽  
Kiyotaka Saito ◽  
Hiroki Inoue ◽  
...  

Indirect laser peening applied to the substrate of austenitic stainless steel with the sheet of similar material. Effects of indirect laser peening condition on the formation of the dimple and the residual stress were investigated in this paper. Shape of the dimple and distribution of the residual stress were measured by laser microscope and X-ray diffraction, respectively. It was observed by the microscope that clean substrate surface of as-received state kept after indirect laser peening because of protection by the sheet. However, fracture of sheet occurred slightly in high pulse energy condition. The diameter and the depth of the dimple by indirect laser peening increased with the increase of laser power. Efficiency of dimple formation decreased with the increase of pulse energy. Affective condition region of indirect laser peening with a combination between the substrate and the sheet of austenitic stainless steel may be limited below the laser power density of 10GW/cm2. It was confirmed that indirect laser peening induced compressive residual stress in the substrate. One of peak of compressive residual stress in residual stress distribution existed near the bottom of the dimple. Residual stress distribution which was produced by indirect laser peening may affect change of quasi bending modulus which was obtained by three-point bending test.


2014 ◽  
Vol 800-801 ◽  
pp. 596-600
Author(s):  
Kai Li ◽  
Tao Chen ◽  
Su Yan Li ◽  
Xiao Ting Wang ◽  
Tao Liu

In this paper, we use the finite element simulation method to create a three-dimensional thermal mechanical coupled model that simulate the distribution of residual stress under condition of hard turning GCr15. And twice consecutive cutting simulation are required, then analysised the influence rule of two consecutive machining on surface residual stress distribution. The simulation results were compared with the experimental values, the results show that the simulated values of continuous cutting was very closed to the experimental values and the simulation results showed a certain reliability, the maximum residual tensile stress value increased significantly as the cutting speed increased.


Author(s):  
Mahenk Kumar Patanaik ◽  
Gaurav Tiwari ◽  
Akshay R Govande ◽  
B Ratna Sunil ◽  
Ravikumar Dumpala

Abstract In the present numerical study, the residual stresses generated during the shot peening process were evaluated using the finite element method. The influence of shot velocity on the residual stress distribution due to the indentation of a rigid shot over the target plate of alloy steel was studied. The finite element package ABAQUS 6.20 is used for simulating the shot peening process considering the target plate to be deformable. A parametric study was performed by introducing strain hardening rate as H1 = 800 MPa, keeping the dimension of target plate same with variation in shot velocity 20, 50, 75, 100, 125, and 150 m/s to check the behavior of residual stress distribution. As the indentation takes place over the metallic target plate, elastic-plastic deformation was observed. The indentation of the shot with a different velocity range causes the difference in the depth and size of the dent and induces the compressive residual stress. For perfectly plastic and the strain hardened material, the residual stress contour was simulated. The simulated results for strain hardened material show the significant change in the compressive residual stress in the sub-surface region of the target plate. It is evident from the results that the shot velocity has a significant effect on the residual stress distribution. The maximum compressive residual stress is achieved when the shot is indented at a velocity of 125 m/s.


Author(s):  
Jae-Soon Jang ◽  
Dave Kim ◽  
Myoung-Rae Cho

The cold expansion method is one of the most popular techniques in the fatigue enhancement processes, and it has been widely used as a means of improving the fatigue resistance for aircraft structures with holes. Cold expanded holes have lower compressive residual stresses on the entry surface rather than the middle and exit surfaces. Due to the nonuniform residual stress distribution, fatigue crack initiation often occurs on the entry surface. This study proposes a new approach to increase the compressive residual stress magnitude at the entry of the hole. The new method is to apply chamfers into holes before the cold expansion process. Split mandrel process was used to cold work the hole with and without chamfers. Both numerical and experimental studies were done to verify the effects of hole chamfers on the residual stress distribution of the cold expanded holes. Finite element analysis (FEA) was conducted in order to see the effects of the chamfer geometries on the residual stress distributions. The FEA results showed an improvement of compressive residual stress magnitudes at the entry position of the cold expanded hole. The numerical results were compared with X-ray diffraction measurements. Fatigue tests were done to compare the fatigue life of the holes with various chamfer sizes and angles. The cold expansion chamfered holes showed a clear improvement in fatigue life over cold expanded holes without chamfers.


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