The Research Of Electrode Force To The Effect Of Nugget Quality

The electrode force is one of the main parameters of the resistance spot welding(RSW). In the process of the RSW, whether the electrode force is stable and adjustable is very important to guarantee the quality of the RSW. But the research in the adjustability of the electrode force is few at the present time. The main target of my subject is, in the case of using the pressure regulation system and the servo blowtorch, to design different electrode force curves and make real-time adjustment of the pressure in the process of RSW, and to study the influence rule of electrode force in increasing the spot weld strength and improving the welding quality.The subject establishes the pressure regulation system, which can be divided into three parts: the mechanical device, the hardware system and the software system. The system supplies a strong support in both hardware and software during the real-time adjustment of the pressure for the subject. The U-shaped pressure curve is the cardinal electrode force curve of the subject, and it can be divided into four curves of different shapes. Then, with the drive set of servo-actuator, we make the RSW tests and the tensile shear tests to the sheets of the 5052 aluminum alloy. According to the experiment results, we compare the four different curves and finally find their rules.The experiment results show that, the four different curves can all be used in the process of RSW and all have their own rules in effecting the tensile strength of the spot-welded joint. Compared with the design of RSW with the constant voltage, the four different kinds of curves can increase the tensile strength of the spot-welded joint in different degrees.In order to prove the commonality of the regular, the tests with the same contents are made with the materials of titanium alloy TA2 and two kinds of aluminum alloy. The experiment results show that, if we follow the design to adjust the electrode force with the four different kinds of U-shaped curves, the rule we get are same in most cases.