| 摘要 |
PURPOSE:To obtain a tough oxygen blowing lance which is hardly bent in spite of the small diameter by calorizing the inside and outside of a low carbon steel pipe and heat treating the pipe. CONSTITUTION:The inside and outside of a steel pipe contg. 0.04% C are calorized to form Al-contg. layers 2, 3, and the pipe is heated to 700-950 deg.C in the air and cooled rapidly with water. The C content in the uncalorized part 1 is increased to 0.06-0.07% by the transfer of C from the layers 2, 3 to enhance the hardness, and a touch oxygen blowing lance which is hardly bent is obtd. The erosion of the lance due to molten steel and the consumption during use are reduced by covering the inside and outside of the lance with refractory layers 4, 5. |
