The characteristics of the modern continuous rolling mill are :(1) the continuous rolling mill is composed of 7 ~ 9 two-high rolling mills. Layout, adjacent frame into 90 each other. Decorate. (2) each frame is separately driven by a dc motor with high adjustment accuracy. The transmission is arranged on both sides of the mill. The latest mill consists of two or three series dc motors directly driving each roll or two through a gear seat. (3) the combination of the continuous rolling mill and the high-efficiency tension reducing mill (see the pipe tension reducing mill) greatly expands the variety and specification of the pipe produced by the continuous rolling mill pipe set, while only one or two pipe blank specifications can significantly simplify the production process and improve the operation rate. (4) the maximum diameter of pipe produced by floating mandrel tandem rolling mill is 168mm, which is due to the restriction of long mandrel (about 30m) weight. Steel tube core rod after rolling out when the temperature is very high (170 ~ 250 ℃), because online recycling, mandrel must be cooled to 70 ~ 80 ℃. The maximum rolling diameter is 426mm. (5) new units are equipped with electronic computers for process control. From the tube billet loading heating furnace to finishing cut pipe all realized automation. (6) use water-soluble smokeless lubricant to lubricate the mandrel. (7) adopt online normalizing technology, etc.