What are the characteristics of welded steel pipe three-roll diagonal piercing machine?

The welded steel pipe three-high skew piercing machine has three active rolls and one head to form a closed ring pass, so the guide plate is cancelled. The shape of the roll is barrel-shaped, and the three rolls intersect with the rolling line at an Angle, and the rolling direction is the same. The perforator can Pierce metal with low plasticity. Fast perforation speed, high speed efficiency;

(1) In the perforation preparation section, because the tube blank is always compressed in three directions, and the ellipse is small, the center of the tube blank will not break during the perforation process, that is, no cavity is formed, which ensures the internal quality of the welded steel pipe.

(2) Because there is no guide tool, there is no problem of scratching the external surface of the guide tool, it can be perforated into high alloy steel and continuous casting tube billets;

(3) Due to the poor tightness of the deformation area, the rolling of thin-wall welded steel pipe is prone to ' tail triangle ' , and even after sticking, so there are still some difficulties in piercing the thin-wall welded steel pipe with the three-roll diagonal rolling machine.

What are the characteristics of welded steel pipe three-roll diagonal piercing machine?

How does the steel pipe move in the process of cross rolling perforation?

In the process of cross rolling perforation, the rolled piece is spiral forward, and the processing deformation is gradually completed with the spiral advance of the rolled piece. The main reasons are:

(1) Two rolls rotate in the same direction;

(2) The roll axis is inclined relative to the rolling line and intersects into an Angle - feed Angle β. When the tube blank is fed into the roll, the friction between the metal and the roll drives the tube blank - welded steel pipe to reverse rotation. At the same time, the roll axis has an inclination β to the rolling axis (blank axis), so the tube blank - welded steel pipe moves towards its axis while advancing. In the deformation zone, every point of the billet - welded steel pipe is spirally moving. That's one spin, one go.

How many stages is the process of cross rolling perforation?

The deformation process of cross-rolling perforation is mainly divided into three stages:

The first stage is the first unstable process:the front end of the tube blank is gradually filled with the deformation zone, that is, the tube blank and the roll begin to contact the front end of the tube blank metal deformation zone, this stage includes a bite and a second bite.

The second stage is the intermediate stabilization process:this is the main stage of the perforation process, from the front end of the tube blank filled with deformation zone to the end of the tube blank began to leave the deformation zone.

The third stage is the second unstable rolling process:the stage where the metal at the end of the tube blank gradually leaves the deformation zone.

There is a clear distinction between stable and unstable processes, which is often seen in production. If there is a difference between the size of the head and the middle of the whole welded steel pipe, the diameter of the front section of the welded steel pipe is generally large, and the diameter of the middle part is more consistent, which is caused by the three process characteristics.