The expander belongs to the LSAW steel tube forming equipment. It uses a conical expansion head to expand in the steel pipe, eliminating the forming pressure and welding stress of the steel pipe, and ensuring the true diameter uniformity of the full-length section of the steel saw pipe. The equipment includes trolley, expander, working sleeve, fixed seat, cylinder, lubrication station, support, hydraulic station and electronic control system. The expander is set in the trolley. The expander is connected with the cylinder through the working sleeve. The expander is composed of expansion head, expansion block, guide plate, traction rod, etc. The utility model relates to a large-scale equipment, which can ensure the shape of the straight seam metal welded pipe and eliminate the stress through the process of sectional mechanical expansion.


The flushed tube is sent to the rotary roller unit on the center line of the expander.  Using the rotating roll device, together with the camera system, the pipe weld is rotated accurately to 12 o'clock position to ensure that the welding can enter the groove of the upper part of the expansion tool during the subsequent expansion period. The lifting cone roller path raises the pipeline to the center line of the expander, and the position is controlled by the displacement sensor in the lifting hydraulic cylinder. The clamping cart moves forward and is controlled by a metal detector to detect the end of the pipe and get stuck. At the same time, the signal is sent to start the feeding roll of the compaction roll, and the position is controlled by the encoder. During operation, metal detectors are arranged at the enlarged diameter end. The front end of the test tube is used to measure the position of the tube. The length of the pipeline is combined with the enlarged diameter head to automatically calculate the optimal number of steps for expansion. The clamp of the fixture can be rotated to avoid damage to the pipe wall. In the process of propulsion, the height of the clamp is adjusted to compensate the straightness deviation of the tube and optimize the straightening effect of the expander.


Using mechanical expander to enlarge the diameter of steel pipe has the following advantages: no matter the wall thickness and yield strength, steel pipe with constant inner diameter can be produced; mechanical expansion can enlarge the wall, high yield strength and large diameter steel pipe, because only one section of steel pipe is enlarged; the diameter of short pipe can be enlarged without adjustment within the prescribed range; The die on the mechanical expansion head is saved to adapt to the expansion of the steel tube in a certain range without replacing the expansion die, and the high efficiency and large caliber steel tube is produced. During the expansion period, the steel pipe can be visually observed. If the steel pipe is broken, the expansion can be stopped immediately to prevent the crack from spreading. After removal or repair, the diameter can be enlarged. The end of the pipe is round and has a precise size. It does not shrink; it can be adjusted when the expansion die wears out.