The Effect of Eccentric and Magnetic Vibrator on AISI 304 Stainless Steel Vibration Welding

• Main Authors: Peng-Shuen Wang, 王鵬舜
• Other Authors: Weite Wu
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/23656402795226839655

碩士 === 國立中興大學 === 材料科學與工程學系所 === 98 === The study of AISI 304 stainless steel vibration welding used by magnetic vibrator under sub-resonant（362Hz）and resonant（376Hz）, and by eccentric vbrator under sub-resonant（59.3Hz）and resonant（60.9Hz）, respectively. Microstructure, residual δ-ferrite content, crystal structure, residual stress and mechanical properties of the weld bead have been investigated by using optical microscope (OM), X-ray diffraction (XRD), and Vickers hardness tester, respectively. By the observation of microstructure, vibration welding can reduce the temperature gradient under resonant frequency, results the refinement of grain size and increase the number of grains. With regard to residual δ-ferrite, it can be observed as primary δ-ferrite grain refinement, the morphology of residual δ-ferrite is discontinuous. It was noted that residual δ-ferrite content was the least 5.5 % in eccentric vibration with resonance frequency. X-ray diffraction analysis showed that there is no change in crystal structure of AISI 304 stainless steel with or without vibration. But the diffraction intensity decreases and FWHM（Full Width at Half Maximum）of X-ray diffraction profile broadened due to increased the internal defects, as a mechanism of stress relief by stacking faults generation. In addition, residual stress can be effectively reduced by vibration welding. There is the least residual stress can be obtained in resonance frequency. To compared with two vibration mode, the eccentric vibration had better stress relief due to eccentric vibration with more directional stress overlay. The hardness was enhanced in vibration welding, the hardness has obvious raised about 7.3% while resonance frequency was applied.