Study on different RH processes to produce pipeline steel-X70

The comparison of different RH processes was presented including the process condition and metallurgical effect. The characteristic of two different RH-processes was analyzed and how to control the bale-ful element and inclusions in pipeline steel were discussed. The TO of LF-RH and RH-LF are 14×10^-6 and 19×10^-6. The micro-inclusion numbers of LF-RH and RH-LF are 2.48/mm² and 2.62/mm². TheN of LF-RH and RH-LF are 53×10^-6 and 38×10^-6. From these practices, the experience for producing high quality oil-pipe steel in the future was accumulated.