Devel opment of Weld Strength Analysis for Dessimilar Metal Friction Welds by Ultrasonic Technique

J. Ocean Eng. Technol. 1988;2(1):135-149.

초음파법에 의한 이종재료 마찰용접강도 해소법의 개발

오세규,김동조

부산수산대학 기계공학과,부산공업대학 기계공학과

Keywords: friction welding, friction weld strength, welding condition, pulse echo method, ultrasonic reflection cofficient, quantitative analysis

핵심용어: 마찰용접, 마찰용접강도, 용접조건, 펄스파법, 초음파 반사계수, 정량해석

Abstract

Friction welding has been shown to have significant economic and technical advantages. However, one of the major concerns in using friction welding is the reliability of the weld quality. No reliable nondestructive test method is available at present for detecting weld quality, particularly in a production environment. Friction welds are formed by the mechanisms of diffusion as well as mechanical interlocking. The severe plastic flow at the interface by forge action of the process brings the subsurfaces so close together that detection of any unbonded area becomes very difficult. This paper presents an attempt to determine the friction weld strength quantitatively using the ultrasonic pulse-echo method. Instead of detecting flaws or cracks at the interface, the new approach calculates the coefficient of reflection based on measured amplitudes of the echoes. It has been finally confirmed that this coefficient could provide the quantitative relationship to the weld quality such as tensile strength, torsional strength, impact value, hardness, etc. So a new nondestructive analysis system of friction weld strength of dissimilar metals using an ultrasonic technique could be well developed.