Micro-alloying TMCP (Thermal Mechanical Control Processing) Q460 steel FCAW (Flux Cored Arc Welding) welding method

The invention discloses a micro-alloying TMCP (Thermal Mechanical Control Processing) Q460 steel FCAW (Flux Cored Arc Welding) welding method. The method comprises the following steps of: 1, selecting a flux cored wire as a welding material; 2, cleaning an assembly, wherein the surface of a bevel and a parent material close to the bevel should be ground and cleaned; 3, determining that t8/5 time is less than 20 s, determining a heat input range above and below a critical thickness (16 mm) according to the t8/5 time: when the thickness of a workpiece is less than or equal to the critical thickness, the range is less than or equal to 17.6 kJ/cm; and when the thickness of the workpiece is greater than the critical thickness, the range is less than or equal to 30 kJ/cm; 4, setting a welding process and parameters of a group of Q460E welding steel pipes by taking the critical thickness (16 mm) for example: performing multi-layer and multi-pass welding by using a single-side welding and double-side forming process, and controlling interlayer temperature below 150 DEG C, wherein welding current of a base layer is 135-145 A, the welding voltage is 19.5-20 V, and the welding speed is 80-120 mm/min; the welding current of a filling layer is 135-160 A, the welding voltage is 20-23 V, and the welding speed is 90-170 mm/min; the welding current of a finishing layer is 160-180 A, and the welding voltage is 21-23 V; and preheating is not performed before welding, and thermal treatment after welding is avoided; and 5, the method can meet the welding requirement of TMCP Q460 steel to obtain the welding joint with good performance.