Risk Assessment of Oxygen Lance Burning Loss Using Bow-Tie Analysis Based on Fuzzy Theory

Table 1

Event symbols and meanings in FT.

Symbol	Event
M1	Molten steel erosion
M2	Nozzle aging
M3	Large return water flow difference
M4	Abnormal oxygen supply
M5	Lower OL position
M6	Cooling water flange damaged
M7	Pipe blockage
M8	Pipeline weld cracking
M9	Larger oxygen pressure
M10	Excessive internal pressure
BE1	Oxygen valve failure
BE2	Oxygen flange failure
BE3	Oxygen pressure monitoring failure
BE4	Switching oxygen timing inappropriate
BE5	OL position shows abnormal
BE6	Lifetime reached
BE7	Nozzle not replaced in time
BE8	Water valve failure
BE9	Backwater flange damaged
BE10	Inlet flange damaged
BE11	OL pipe scaling
BE12	OL pipe not cleaned in time
BE13	Design defect
BE14	Water vapor condensation
BE15	Abnormal water circulation