Abstract: The weldability of the home-made plain carbon structural steel SS41 (non-welding steel) was studied.A comparative test was made for the Q235 steel with the same composition and plate thickness.It is shown that the weld joint of SS41 steel welded by the low hydrogen electrode E4315 (by hand electric arc welding) and H08A welding wire added with HJ431 welding flux (by-submerged arc welding) has mechanical property corresponding to that of Q235 steel.The SS41 steel can be substituted for Q235 steel,is used for important welding structures.