Development of HRSG-purposed Extra-long/Light-wall Steel Pipe as Hot-rolled with CPE Push Bench Mill

Described on the basis of characteristics of the CPE push bench mill are the manufacturing process flow and the technical control-related difficulties for the hot-rolled HRSG-purposed extra-long/light-wall pipe. Also proposed here are the countermeasures against the problems concerning control of wall thickness homogeneity and drawing-caused concave defect，inner surface quality，and property control，etc. Relevant operation result shows that drawing-caused pipe breaking failure rate can be greatly reduced，and occurrence of drawing-caused concave defects can also be well prevented by means of optimizing deformation distribution，mill pass，and properly controlling of mandrel size and temperature so as to ensure consistent production of the 3.0~3.3 mm HRSG-purposed light-wall pipes. Moreover，the properties of the said small-sized pipe can also be consistently controlled by means of such techniques as the post-descaling/before stretch-reducing medium-frequency induction heat making-up，and control of the post-stretchreducing cooling velocity.