| 摘要 |
PCT No. PCT/GB92/01757 Sec. 371 Date Mar. 23, 1994 Sec. 102(e) Date Mar. 23, 1994 PCT Filed Sep. 24, 1992 PCT Pub. No. WO93/06957 PCT Pub. Date Apr. 15, 1993.A metallurgical dart includes an enlarged refractory head having a top, a bottom, and a central through hole extending from top to bottom of the head and lined with a metallic sleeve, with a portion of the lining sleeve projecting beyond the top and/or bottom of the head; an elongate tail of refractory material with an external and/or internal metallic element and of external diameter slightly less than the internal diameter of the lining sleeve, such that the tail can pass, as a close fit, through the lining sleeve of the head; and at least one crimped or other joint between the metallic element of the tail and the projecting portion of the lining sleeve, to fix the head and tail together. |
