Continuous pipe mill

The continuous rolling mill is to wind the capillary tube on the long mandrel, and roll it into a steel pipe through a continuous rolling mill in which multiple racks are arranged in sequence and the adjacent rack rolls are offset by 90°. There are two types of continuous rolling mills: one is a long mandrel mill with free movement of the mandrel along with the pipe, referred to as MM; the other is the mandrel that is restrained at the time of rolling, the speed-controlled core Rod rolling mill, referred to as MPM.

The main advantages of a continuous tube mill are:
(1) High productivity, the annual output of most units is about 25-300,000 tons, and some units reach 56.2 tons (equivalent to 300 pieces/h or 80t/h). The design of a 42-146 unit with a new design. The capacity is 750,000 t/a.
(2) The quality of the steel pipe is high, and it can produce boiler pipes, oil well pipes and medium and low alloy steel pipes. The surface quality and dimensional accuracy of steel pipes are better than those of automatic pipe mills.
(3) It is possible to roll a long pipe with a pipe length of up to 33 m and a length of 160 to 165 m after the tension reducing machine. The continuous rolling mill machine creates the conditions for the superiority of the tension reducing machine, and the tension reducing machine provides the possibility of simplifying the tools, expanding the variety and improving the economic efficiency of the continuous rolling mill.
(4) The continuous rolling mill can bear a large amount of deformation (generally, the μz is about 3.5 to 5), and the required capillary is thicker, so the quality of the tube blank can be lower than that of the automatic tube rolling machine.
(5) High mechanization and automation with few operators.
(6) The cost of steel pipes is relatively low, which is mainly due to higher unit productivity, low metal consumption and less depreciation per ton of pipe. For example, the metal consumption coefficient of the continuous rolling mill unit is 1.07 to 1.095 (1.06 to 1.075 when there is no core tension reduction), and the automatic rolling unit is 1.10 to 1.15. The continuous rolling mill unit using continuous casting billet as raw material can compete with the welded pipe. Therefore, the continuous rolling mill unit is the most economical method for producing small-diameter seamless steel tubes.