a study on the role of effective parameters on the mechanical properties of gas pressure welded rebars

Gas pressure welding (gpw) is a type of solid-state welding developed as a branch of the oxyacetylene fuel gas welding process (ofw) that employs mechanical pressure. one of the main advantages of gpw is the reduction of rebar waste, as well as enhancing buildings’ earthquake resistance due to the high strength of the rebar connection points. in this research, the factors affecting gpw and the mechanical properties of gas pressure-welded rebars were investigated. tempcore rebars with diameters of 18 and 25 mm were welded at different pressures (17 to 21 mpa for 18 mm diameter and 22 to 28 mpa for 25 mm diameter) and varying times (40 to 60 seconds for 18 mm diameter and 60 to 110 seconds for 25 mm). tensile, bending, and microhardness tests were conducted on the samples to evaluate their final properties. additionally, the microstructure of the samples was examined using both optical and scanning electron microscopes. the results indicate that for tempcore rebar, increasing pressure and heating time decreases the likelihood of forming oxide layers, resulting in improved ductility of the samples. the tensile test results show that longer heating times provide greater opportunities for recrystallization. the bending test results reveal that reduced pressure and welding time lead to brittleness in the samples, attributed to the presence of oxide particles and delayed recrystallization. microhardness results show that the highest values are associated with samples welded at low pressure and low welding times.