Low alloy steels are particularly used in the manufacture of several products such as storage tanks, oil and gas pipelines, industrial equipment and many agricultural and construction machinery parts that may experience service failure, and thus may require repair through welding processes. The weldability of steel is determined by its susceptibility to cracking, which can be prohibited by using certain welding procedures, which are often costly and difficult to use. Submerged arc welding of low alloy steels (AISI 5147) was implemented, firstly without nickel additives, followed by adding nickel to powder flux with a wide range (10, 20, 30, 40 and 50 wt. %). X-ray Inspection, tensile test and energy dispersive spectrometer were then utilized to evaluate the resulting welds. Results revealed that the tensile strength and weld joint efficiency were reached to (845 MPa) and (112 %) respectively when 20 wt. % of nickel was added to flux.