Immersion lance for injecting gas or powder into molten metal - esp. into steel, where lance tube is reinforced by tubes carrying coolant

摘要

The lance is formed by a metal tube (I), reinforced by longitudinal ribs consisting of metal tubes (II) through which a coolant flows. Tubes (II) are welded onto tube (I), and the assembly (I) and (II) is sheathed in a nonmetallic refractory material. The bottom ends of tubes (II) are pref. joined together by transverse channels to form a closed cooling circuit. Alternatively, the bottom ends of tubes (II) pref. have nozzles via which the coolant enters the lance tube (I), and tubes (I) and (II) are pref. fitted with uniformly spaced anchors which securely locate them in the refractory sheath. The outer dias. of tubes (II) are pref. 0.4-0.6 times the outer dia. of tube (I). The life of the lance is greatly increased as compared with the lance described in DT 2626892.