The Academic Study Of Rolling For PQF

The so-called premium quality finishing (PQF) mill is the world's most modern Continuous Rolling mill at present, and PQF plant represents an important leap forward in the technology of seamless tube manufacture. It produces large quantities of seamless steel tubes at a high level of quality and profitability. The world's first PQF plant had been put into production in Tianjin Pipe Corporation at the end of 2003. Compared with the conventional MPM mill, forming is more homogeneous and the product quality is higher, also and even higher-alloy steel grades have been successfully processed. At present, the research about technology for PQF is still vacancy. Also the technology for PQF is different from that of MPM. So, the academic study of rolling for PQF is important for production and variety exploiture. This paper which is based on the PQF mill of Tianjin Pipe Corporation introduces the academic study of rolling for PQF applying finite element software ANSYS, open out the trait of PQF at the same time. The main research contents and progresses are as follows:(1) For the change-over from 2-roll to 3-roll technology, the material flow is more uniform, and the ballooning between the roll gap is smaller, and also dimensional deviations in wall thickness are smaller.(2) Material deformation of PQF technology is homogeneous compared with MPM technology concluded by the study of strain. So the probability of tension fracture of PQF technology is on the small side..(3) For the change-over from 2-roll to 3-roll technology, the roll stress is lower and more uniform, also the force of each roll is lower. So, the wearing of roll and mandrel is lower.(4) For the change-over from 2-roll to 3-roll technology, the maximum dispersion of line speed of roll is smaller, and the wearing of roll is more homogeneous, also and the dimensional precision of wall thickness of product is higher.(5) Compared with MPM technology, the stress of mandrel of PQF technology is lower. So the condition of mandrel is improvement, and the lifespan of mandrel has increase. And it is a feasible measure to increase the speed of mandrel for improving the lifespan of mandrel concluded by the study of friction force and draught pressure under different speed of mandrel.(6) It is concluded that the primary influencing factor for the temperature field of mandrel is the conduction between the mandrel and the pipe, and that surface temperature of mandrel changes rapidly based on the study of the mandrel's temperature field during rolling.