what does 7018 mean in welding_welding electrode number chart

        Cast iron welding rod is a welding rod used for cast iron, characterized by high strength and good plasticity. It is suitable for gray cast iron and ductile iron, and can be machined.
        Cast iron is usually classified according to the distribution of carbon in cast iron, and can generally be divided into white cast iron, gray cast iron, ductile cast iron, vermicular cast iron and malleable cast iron. Due to the high carbon content, uneven structure, low plasticity and poor weldability of cast iron, it is very easy to produce defects such as white cast iron, cracks and pores during welding. Special attention should be paid to the selection of welding process and welding materials during welding. For welding rod arc welding, it can basically be divided into two categories, one is the homogeneous weld type, namely cast iron type; the other is the heterogeneous weld type such as: steel (carbon steel or alloy structural steel, etc.), pure Ni (pure nickel 308), Ni-Fe (nickel iron 408), Ni-Cu (nickel copper 508), Ni-Fe-Cu, Fe-Cu, etc. When selecting welding rods, you can choose according to different cast iron materials, different cutting requirements, different service conditions and importance, different structural characteristics, stiffness, etc.