The development history of the continuous tube mill has a long history. After the tension reducing machine came out in the United States in 1932, with the continuous improvement of the tension reducing technology and the rapid development and application of computer technology, the continuous tube mill has been used in the production process and equipment. With each passing day, it has been developed and promoted rapidly. The development of the continuous tube mill is divided into four stages, namely, the full floating mandrel continuous tube mill, the semi-restricted/restricted core continuous tube mill, the Mini-MPM and the PQV rolling mill. On the basis of the floating mandrel continuous rolling mill, the limited-movement mandrel rolling mill conducted process tests in the mid-1960s and obtained gratifying results. In 1978, the world's first fixed-moving mandrel continuous rolling mill (MPM) was completed and put into production at the Italian Dalmin Steel Pipe Plant, and the continuous rolling process reached a new level. In the late 1990s, the three-roll continuous tube rolling mill (PQF) technology was introduced, which made the continuous tube rolling process equipment leap to a higher level. The changes in each stage of it will cause great changes in the production process and technical equipment. The change from a floating mandrel to a constraining mandrel improves the effect of the slub problem on the wall thickness accuracy. As the mandrel becomes shorter, it is possible for the continuous rolling mill to produce large-diameter tubes.
The continuous tube rolling mill is a high-efficiency rolling mill with multiple stands (7-9 stands) and few stands (3-4 stands). There are two ways of mandrel movement: one is that the mandrel moves freely with the tube during tube rolling, and the continuous rolling tube at this time is called floating mandrel continuous rolling tube; the other is that the mandrel motion speed is restricted during tube rolling. Control, the continuous rolling tube at this time is called the limited mandrel continuous rolling tube.
