Abstract: The factors affecting the calcium yield of pure calcium wire were studied through theoretical analysis and production practice. The results show that,1) Reducing the diameter of feeding tube can reduce the deflection of and the pilling up of calcium wire；2) The effective absorption range of calcium is from 0.3 m above the bottom to 1.22 m below the liquid level; 3) The feeding speed of calcium wire is affected by the algam thickness of  calcium wire, and the  calcium wire with different algam thickness has an optimal feeding speed；4) When feeding wire at the downward flow position of argon bubble flow, the calcium yield is better than that at the upward flow position of argon circulation flow；5) The calcium yield of wire packing with seamless is better than that with slit algam tube；6) The composition of molten steel affects the vapor partial pressure of calcium, the effective absorption range of calcium is changed, and then the residence time of calcium in molten steel is different.

Key words: calcium treatment, yield, nozzle clogging, calcium core wire