Abstract. The objective of the project was to develop a method allowing for detailed characterization of welding particles including particle number concentration, size distribution, surface chemistry and chemical composition of individual particles, as well as metal concentration of various welding fumes in personal exposure samples using regular sampling equipment. A sample strategy was developed to evaluate the variation of the collection methods on mass concentration. Samples were collected with various samplers and filters at two different locations using our collection system. The first location was using a robotic welding system while the second was manual welding. Collected samples were analysed for mass concentration using gravimetry and metal concentration using ICP/OES. More advanced analysis was performed on selected filters using X-Ray Photoelectron Spectroscopy to determine surface composition of the particles, and X-Ray Diffraction to determine chemical composition of the fumes. Results showed that the robotic system had a lot of variation in space when the collection system was located close to the weld. Collection efficiency was found to be quite variable depending upon the type of filter. As well, metal concentrations in blank filters were dependent upon the type of filter with MCE presenting with the highest blank values. Results obtained with the XRD and XPS systems showed that it was possible to analyse a small of powdered welding fume sample but results on filters were not conclusive.

Since the advent of the friction welding process in 1956 and its early application, it has been followed by comprehensive investigations and considerable research effort has been made in U.S.S.R. Japan. U.K. U.S.A. and Europe to find out the most appropriate friction welding process conditions for welding certain pairs of different sizes and configurations. Despite this considerable work, the understanding of the basic mechanism involved in friction welding did not keep pace with the rapid increase in industrial application of the process. This was Probably due to partly relative insensitivity of the weld quality to variation in process control parameters; speed, pressure and burn off and partly to the fact that complex mechanisms are involved in the friction generation of heat and the consolidation of the weld. In this research, it has been deliberated to identify basic or minimum requirements in connection with the production of sound friction welds of mild steel work Pieces. Minimum energy input per unit area of the weld has been calculated and process parameters are recommended for production of sound welds in the mild steel work pieces of round and tabular cross-sections. Mechanical tests have been carried out on test samples welded by friction welding. Results have been discussed.