A four-roll cross-rolling piercing machine

Abstract

The four-roller cross-rolling piercer of the present invention is arranged with four tapered rolls, and the four tapered rolls are evenly distributed along the center of the workpiece at 90°; every two tapered rolls in the four tapered rolls A pair of working tapered rolls is formed; the distance ratio between the two pairs of tapered rolls is 1.06-1.09, and the four tapered rolls have their own independent driving power devices; the rotation directions of the four tapered rolls are the same. The tapered roll is connected with a shaft coupling, the shaft coupling is connected with a gear box, the gear box is connected with a motor, and the tapered roll is connected with a frame through a pressing device. The drive power unit consists of a permanent magnet synchronous torque motor and a bevel gearbox. The four-roll rotary piercer has actively rotating heads.

Description

technical field [0001] The invention belongs to the technical field of cross-rolling and piercing of seamless steel pipes, and in particular relates to a four-roll cross-rolling piercing machine. Background technique [0002] At present, the production equipment widely used in the field of seamless steel pipe production is two-roll cross-rolling piercing machine and three-roll cross-rolling piercing machine. [0003] The two-roll cross-rolling piercer can be divided into three types according to its roll shape: barrel roll (roll type) piercer, tapered roll (bacteria type) piercer and disc roll (disc type) piercer (see figure 1 ). The two-roll cross-rolling piercer is generally equipped with a guide plate or a guide plate between the roll gaps to form a closed deformation zone. However, no matter which type of roll is used, a cavity may appear in the center of the rolled piece during the piercing process. The appearance and continuous expansion of cavities are the main rea...

AI Technical Summary

Problems solved by technology

[0009] 1. Difficulty in biting - the biting angle of the two-roll cross-rolling piercing machine is too large, and the biting conditions are not good. When the tube blank touches the plug, the rolled piece and the roll will slip, causing jamming

Three-roll cross-rolling piercing machine, because the rolled piece only bears three-dimensional compressive stress, the central structure will not be loose. When the tube blank touches the plug, the excessive axial pressure will also cause the rolled piece and the roll to slip, resulting in the plug wear out too fast

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