The Environmental Impact of Ecological Rehabilitation Techniques Applied to Statically and Variably Stressed Welded Structures

There are many welded structures in the world such as bridges and viaducts that are subject to fatigue. Some of these structures, generally made of non-alloy or low-alloy steels, have been put into operation many years ago and have accumulated a large number of variable load cycles over time. For this reason, the occurrence of the fatigue phenomenon is inevitable and consists in the occurrence of failures at stresses applied to the structure, below the yield limit of the material. These stresses under the static loads would not cause the failures to appear. This paper will investigate if the ecological reconditioning techniques “weld toe grinding” and “WIG re-melting weld toe,” influence favourably the behaviour of the welded structures made from HSLA steel, in static and variable loads, if the application of these techniques is justified in both cases and finally which is the environmental impact of applying these techniques. In the paper we will present the chemical composition and mechanical properties of the base and filler materials, micro and macrostructures, graphics with the variation of the micro-hardness, we will perform static and fatigue tensile tests and we will rise the durability curve in the case of the fatigue tests. We will also present a mathematical computational algorithm, which highlights the extent to which these ecological rehabilitation techniques pollute the environment. It is more efficient both for technological and ecological reasons to recondition a product than to manufacture it from the very beginning.