Electric arc fusion welding-braze welding method of niobium and steel

The invention discloses an electric arc fusion welding-braze welding method of niobium and steel, which comprises the following steps: firstly, carrying out surface treatment on a steel weld assembly; secondly, carrying out acid pickling on a niobium weld assembly; and thirdly, welding by an argon tungsten-arc welding method. In the invention, welding in non-vacuum environment is realized; the limit of vacuum braze welding on the size of a welding work piece is avoided; mixed gas of helium and argon is used as protective gas of a welding gun, thus improving the spreadability of brazing filler metal on the surface of niobium; and a pure nickel welding wire is used as a filling material, thus solving the problem that a joint is tendered because a fragile phase can be easily formed by niobium and steel at high temperature, realizing the reliable connection of niobium and steel, and being especially applicable to braze welding connection of niobium and steel in chemical equipment of a niobium steel composite plat