Submerged-arc flux for low-temperature impact of Cr-Mo heat-resistant steel and narrow-gap submerged-arc welding and preparation method thereof

The present invention discloses a heat-resistant chromium molybdenum steel, and low-temperature impact submerged arc flux for submerged arc narrow gap, relates to the field of welding, the mass percentage of the flux components is: SiO2 8-20%; MgO 20- 40%; Al2O3 15-30%; ΣCaO 15-28%; MnO 0.5-5%; Na2O 0.5-2%; K2O 0.5-2%; TiO20.5-3%; Fe2O3≤3.0%; S≤0.030%; P≤0.030%. Electrode submerged arc welding flux of the present invention is designed to solder under the narrow gap welding and heat-resistant chromium molybdenum steel, low-temperature impact.