Member of the self-shield flux cored wires.Adding slag-forming agent, deoxidizer and denitrification agent with an appropriate melting point, which can be directly welded without shielding gas, and good welding characteristics can be obtained.The designs of cored flux utilize the principle of slagging and gas production of metallurgical reaction to demonstrate the joint protection of gas slag in the molten pool.It delivers efficiency 3~5 times of regular manual welding.