High-toughness high-welding speed sintered flux suitable for submerged-arc welding of X90/X100 ultrahigh-strength pipeline steel pipe

The invention discloses a high-toughness high-welding speed sintered flux suitable for the submerged-arc welding of an X90/X100 ultrahigh-strength pipeline steel pipe, and the high-toughness high-welding speed sintered flux comprises the following components in percentage by weight: more than or equal to 15 and less than or equal to 20 of CaF2, more than or equal to 20 and less than or equal to 25 of MgO, more than or equal to 15 and less than or equal to 20 of Al2O3, more than or equal to 10 and less than or equal to 15 of CaO, more than or equal to 1 and less than or equal to 5 of MnO, more than or equal to 25 and less than or equal to 30 of SiO2, more than or equal to 3 and less than or equal to 8 of Y2O3 and more than or equal to 1 and less than or equal to 4 of a reducing agent. The high-toughness high-welding velocity sintered flux disclosed by the invention ensures that the submerged-arc welding speed of the X90/X100 ultrahigh-strength pipeline steel pipe is at the high welding speed of 1.5-1.8 m/minute, has good processing property of a welding seam, achieves the welding strength of more than 780 MPa, achieves the average toughness value of 130 J, achieves the deposited metal strength of more than 760 MPa, achieves the diffusible hydrogen content of less than 6.0ml/100g (mercury method), belongs to a low-hydrogen welding material and can realize the high-strength high-toughness matching of the submerged-arc welding seam of the ultrahigh-strength pipeline steel pipe.