New technology for measuring resistance of electrical contact and estimating welding quality

Abstract

Incomplete penetration is a common defect in the welding gap of large size (welding area is over 100 mm 2 ) electrical contact, which leads to an instability of welding quality. Nevertheless, there was limited research dealing with non-destructive quality inspection of electrical contact. In this research, the resistance of CJ400 electrical contact was measured with the device medium frequency inverter resistance spot welding (MFI-RSW) machine. Multipulse measuring method was designed and proved efficient to reach a higher accuracy by restraining the influence of the contact resistance between electrodes and electrical contact. Moreover, the error of resistance caused by temperature rising in the measuring process is also eliminated effectively. Therefore, more accurate resistance of electrical contact could be extracted compared to the method of single pulse measuring. Then, the relationship between resistance and welding quality was studied and a new quality inspection method was proposed.

Equal Load-Carrying Design of Lapped Joints of Al–Cu Dissimilar Materials

“…Prior to brazing, it was necessary to select the appropriate brazing filler metal, in order to determine the parameters in Equation (1). Among the filler metals, 1060 pure aluminum [ 15 ] and H62 brass [ 16 ] were selected as the base materials, (both equipment’s and chemicals are from Hegang Shanghai Welding Co., LTD, Shanghai, China) while the corresponding chemical compositions are presented in Table 1 and Table 2 (equipment from Hegang Shanghai Welding Co., LTD, Shanghai, China), and the corresponding tensile strengths are presented in Table 3 . The softening coefficient of base metal was related to the specific brazing process.…”