Complex sentence: In addition, it does not require the substrate preparation such as pre-cleaning of surfaces as that required by welding process which contributes to reduce the joining cost and environmental impact (since chemical cleaning is not required).
Split into simpler sentences: In addition, it does not require a substrate preparation such as pre-cleaning of surfaces which is required for welding processes. This fact contributes to reduce the joining costs and the environmental impact (since chemical cleaning is not required).