The invention relates to a fused flux used for
welding 9Ni steel and a preparation method of the fused flux, and belongs to the field of
welding materials. The fused flux comprises, by weight, 45-47 parts of
wollastonite, 15-17 parts of CaF2, 25-27 parts of marble, 12-15 parts of
potassium feldspar, 5-7 parts of ZrO2, 5-7 parts of MgO, 0.1-0.5 part of
manganese ore, and 2.5-5 parts of BaO. The preparation method comprises the steps of material preparation,
smelting,
pelletizing, crushing and screening,
drying, and packaging, wherein the
granularity of the fused flux is 10-80 meshes. The fusedflux has the characteristic of good
moisture-absorption resistance and is used in cooperation with an ERNiCrMO-4
nickel-based
welding wire according with ASMEIISFA-5.14, the
weldability and the mechanical performance of weld joints are good, the tenacity of
weld metal at an ultralow temperature is stable and good, and the anti-heat-crack sensitivity is good.