SU1731369A1 - Method of sizing welded double-seam pipes by hydromechanical expander - Google Patents

Abstract

Use: calibration of welded two-seam pipes. The welds of the pipe are oriented relative to the grooves on the tool and are cyclically deformed with segmental heads moving apart in the radial direction. After each dispensing cycle, the pipe is rotated around its longitudinal axis by 180 ° and move along the axis a step with the overlap of adjacent areas by an amount determined on the given mathematical dependence. 1 tab.

Description

The invention relates to the processing of metals by pressure and can be used in the calibration of large diameter welded two-seam pipes on hydromechanical expanders.

There is a known method for calibrating welded pipes, which includes orientation of the weld with respect to the groove on the working surface of the tool and dispensing the pipe in successively repeated cycles in sections using segments that move apart in the radial direction with overlapping adjacent sections.

The disadvantage of this method when calibrating 2-seam pipes is that it does not provide high quality finished products due to the large longitudinal curvature of the pipes.

The aim of the invention is to improve the quality of finished products by reducing the longitudinal curvature of the pipes.

The essence of the invention is that the welds are oriented relative to the grooves on the working surface of the tool and the pipe is distributed in successive cycles in sections with overlapping adjacent lanes through the segments moving apart in radial directions, and after each cycle of distribution the pipes are rotated 180 ° around its longitudinal axis, and the amount of overlap of adjacent areas I is determined from the dependence

vi

with

with about about

I 1,1 V 1,002 (Rtr-Games) ptr,

2

where 1,002 - coefficient taking into account the deformation of the pipe within the elastic range;

DTp is the outer diameter of the finished pipe;

hip - pipe wall thickness.

The method is carried out as follows.

The pipe installed on the master carriage, by turning the support rollers, is oriented with welds relative to the grooves on the expander tool and is set on the calibrating head of the expander. The pipe sections are distributed by segments of the head, moving apart in the radial direction. When the desired degree of deformation is reached, the segments are reduced to the initial position and the support rollers turn the pipe by 180 ° around its longitudinal axis. The driver carriage moves by the amount of I at which the overlapping of adjacent distribution areas is ensured

I 1.1 VT002 (Rtr - hTp,

2

where 1,002 - coefficient taking into account the deformation of the pipe within the elastic range;

DTp is the outer diameter of the finished pipe;

hip - pipe wall thickness.

The distribution cycle is repeated. Thus, the pipe is calibrated along its entire length, rotated by 180 ° around its longitudinal axis after each cycle and providing a specified amount of overlapping adjacent areas

Example. Welded two-seam pipes with dimensions of 1420x15.7 mm, length 11.2 m of steel X-70 on a hydromechanical expander, the calibration head of which consists of 8 segments extending in the radial direction of the working section length equal to 1300 mm, were calibrated. On two opposite segments of the gage head there are grooves in which the internal welds of the pipe are located at. calibration.

The tubes were calibrated with the same degree of residual deformation equal to 0.45%, in sections with repeated dispensing cycles with a rotation of 180 ° after each

five

0

five

0

For the second cycle, the support rollers of the master car and the overlap of adjacent sections I 50-300 mm.

The longitudinal curvature of the pipes was measured in the middle of the length of the pipe by the deviation of the diametrically opposed ones forming from the string stretched along its entire length.

The results of the comparative tests of the proposed and known methods are given in the table.

As can be seen from the table, turning the pipe through 180 ° after each cycle with the calculated overlap of adjacent sections allows improving the quality of the pipes by reducing the longitudinal curvature of the pipes by 2-3 times.

Claims (1)

Invention Formula A method for calibrating welded two-seam pipes on hydromechanical expanders, including orientation of the welds relative to the grooves on the working surface of the tool and dispensing the pipe in successive cycles in sections with overlapping adjacent areas through segments that move apart in radial directions, characterized by improving the quality of finished products by reducing the longitudinal curvature of the pipe; after each dispensing cycle, the pipe is rotated 180 ° around its longitudinal axis, and erekryti adjacent sections is determined from the relationship I 1.1 V 1,002 (RTP -prtr) Ntr 2 where 1,002 - coefficient taking into account the deformation of the pipe within the elastic range; DTp is the outer diameter of the finished pipe; hTp is the pipe wall thickness.