In order to maintain the structural consistency during the welding of precipitation hardened copperchromium-zirconium(PH-CuCrZr)alloy components,electron beam welding(EBW)process was employed.Experimental study and nu...In order to maintain the structural consistency during the welding of precipitation hardened copperchromium-zirconium(PH-CuCrZr)alloy components,electron beam welding(EBW)process was employed.Experimental study and numerical modeling of EBW process during welding of PH-CuCrZr alloy components were carried out.A 3D finite element model was developed to predict the output responses(bead penetration and bead width)as a function of EBW input parameters(beam current,acceleration voltage and weld speed).A combined circular and conical source with Gaussian heat distribution was used to model the deep penetration characteristic of the EBW process.Numerical modeling was carried out by developing user defined function in Ansys software.Numerical predictions were compared with the experimental results which had a good agreement with each other.The developed model can be used for parametric study in wide range of problems involving complex geometries which are to be welded using EBW process.The present work illustrates that the input current with a contribution of 44.56%and 81.13%is the most significant input parameter for the bead penetration and bead width,respectively.展开更多
Friction and wear studies enable the investigation of material interaction between two sliding surfaces in contact. In the present investigation, the coefficient of friction and the wear resistance of AISI 316 L parts...Friction and wear studies enable the investigation of material interaction between two sliding surfaces in contact. In the present investigation, the coefficient of friction and the wear resistance of AISI 316 L parts were studied under self-mating, dry sliding conditions using a pin-on-disc type configuration. The experiments were conducted at vacuum based high temperature pin-on-disc tribometer. The 4 mm diameter pin and 180 mm diameter disc were subjected to varying sliding velocities(0.5, 0.75 and 1.5 m/s) and were operated in 200, 400, 500 and 580 ℃ temperature at 600 Torr vacuum. The variation of specific wear rates with sliding velocities and different environmental conditions was studied. The morphology of sliding/rubbed surfaces was observed using Scanning Electron Microscope. In summary, it was found that a severe to mild wear transition occurred in sliding under operating conditions. Increased wear rates have been observed for 500 and 580 ℃ with increasing sliding velocity. Adhesive wear has been found to be predominant at 500 and 580 ℃ where as de-lamination has been observed at ambient temperature,200 and 400 ℃ in vacuum. The present paper also carried out the numerical analysis of the vibration behavior of AISI 316 L under thermal environment. Results revealed that at high temperature vibrational amplitude and natural frequency is significantly reduced. This can be attributed to the reduction in stiffness of the material at elevated temperatures. This high amplitude vibration during service can lead to high wear rate.展开更多
文摘In order to maintain the structural consistency during the welding of precipitation hardened copperchromium-zirconium(PH-CuCrZr)alloy components,electron beam welding(EBW)process was employed.Experimental study and numerical modeling of EBW process during welding of PH-CuCrZr alloy components were carried out.A 3D finite element model was developed to predict the output responses(bead penetration and bead width)as a function of EBW input parameters(beam current,acceleration voltage and weld speed).A combined circular and conical source with Gaussian heat distribution was used to model the deep penetration characteristic of the EBW process.Numerical modeling was carried out by developing user defined function in Ansys software.Numerical predictions were compared with the experimental results which had a good agreement with each other.The developed model can be used for parametric study in wide range of problems involving complex geometries which are to be welded using EBW process.The present work illustrates that the input current with a contribution of 44.56%and 81.13%is the most significant input parameter for the bead penetration and bead width,respectively.
文摘Friction and wear studies enable the investigation of material interaction between two sliding surfaces in contact. In the present investigation, the coefficient of friction and the wear resistance of AISI 316 L parts were studied under self-mating, dry sliding conditions using a pin-on-disc type configuration. The experiments were conducted at vacuum based high temperature pin-on-disc tribometer. The 4 mm diameter pin and 180 mm diameter disc were subjected to varying sliding velocities(0.5, 0.75 and 1.5 m/s) and were operated in 200, 400, 500 and 580 ℃ temperature at 600 Torr vacuum. The variation of specific wear rates with sliding velocities and different environmental conditions was studied. The morphology of sliding/rubbed surfaces was observed using Scanning Electron Microscope. In summary, it was found that a severe to mild wear transition occurred in sliding under operating conditions. Increased wear rates have been observed for 500 and 580 ℃ with increasing sliding velocity. Adhesive wear has been found to be predominant at 500 and 580 ℃ where as de-lamination has been observed at ambient temperature,200 and 400 ℃ in vacuum. The present paper also carried out the numerical analysis of the vibration behavior of AISI 316 L under thermal environment. Results revealed that at high temperature vibrational amplitude and natural frequency is significantly reduced. This can be attributed to the reduction in stiffness of the material at elevated temperatures. This high amplitude vibration during service can lead to high wear rate.
