Spot welding

About: Spot welding is a research topic. Over the lifetime, 12491 publications have been published within this topic receiving 89845 citations. The topic is also known as: Spot_welding.

Spot Weld Analysis With 2D Ultrasonic Arrays.

Abstract: This paper describes a threefold method of testing the performance of an array-based ultrasonic tool for nondestructive testing of spot welds. The tool is described in its capabilities, use, and advantages over existing counterparts. Performance testing for and the results from carrying out the testing are described. The three performance testing methods include 1) the use of calibrated samples, 2) comparisons with actual spot-welds, and 3) a performance evaluation of the embedded fitting software. The test of the fitting software was carried out by a comparison of results with reference fits supplied by the National Institute of Standards and Technology.

Mechanical behaviour of a new automotive high manganese TWIP steel in the presence of liquid zinc

Abstract: High manganese TWIP (TWinning Induced Plasticity) steels are particularly attractive for automotive applications because of their exceptional properties of strength combined with an excellent ductility. However, as austenitic steels, they appear to be sensitive to liquid zinc embrittlement during welding, the liquid zinc arising from the melted coating due to the high temperatures reached during the welding process. In this framework, the cracking behaviour of a high manganese austenitic steel has been investigated in relation to the liquid metal embrittlement (LME) phenomenon by hot tensile tests carried out on electro-galvanized specimens using a Gleeble 3500 thermomechanical simulator. The influence of different parameters such as temperature and strain rate on cracking behaviour has been studied. Embrittlement appears within a limited range of temperature depending on experimental conditions. Conditions for which cracking occurs could be experienced during welding processes. The existence of a critical stress above which cracking appears has been evidenced and this critical stress can be used as a cracking criterion. Finally, the study of the influence of different parameters such as time of contact between steel and liquid zinc before stress application, coating and steel on LME occurrence provides understanding elements of LME mechanism and permits to suggest solutions for preventing cracking during spot welding of such steels.

Advanced Approach to Modify Friction Stir Spot Welding Process

Abstract: Nowadays, friction stir spot welding (FSSW) is used in automotive, rail vehicle construction, the aerospace industry, and electrical industry. In the current research, a modified version of the FSSW process entitled friction stir spot vibration welding was introduced to join Al5083 specimens. The joining specimens were vibrated normal to the tool movement direction, while the joint position cooled by passing coolant through the fixture. Different characteristics of developed joint namely microstructure, mechanical properties, corrosion behavior were studied. The results showed that stir zone grain size decreased significantly as the vibration was employed and the joint position was cooled. It was found that vibration enhanced the dynamic recrystallization and coolant decreased the grain growth. Both led to enhanced grain refinement in the stir zone. The results also indicated that shear strength and hardness of the weld region increased as the modified version of FSSW was applied. Corrosion tests revealed that corrosion resistance increased as the modified method was applied.

A new method for nondestructive quality evaluation of the resistance spot welding based on the radar chart method and the decision tree classifier

Abstract: To develop an effective nondestructive evaluation method for the welding quality of the resistance spot welding, the electrode displacement signal during the resistance spot welding process is monitored, and the acquisition data of the signal are innovatively presented as the radar chart format. Some geometric features of the radar charts are extracted to reflect the welding quality. The decision tree classification technique is adopted to build a classifier and to provide a visible and intuitive diagnostic procedure for welding quality assessment. Test results of the decision tree classifier show that it is feasible and reliable to evaluate weld quality based on the graphics features of the radar chart. The features and the weld quality are closely related, and their extraction avoids complex algorithm. Meanwhile, when there are small samples, the decision tree classifier can identify good or bad weld accurately and rapidly, even though the weld is from an abnormal welding process, such as expulsion, current shunting, greasy surface, and small edge distance condition.