SU1274890A1

SU1274890A1 - Method of producing straight-seam pipes

Info

Publication number: SU1274890A1
Application number: SU843793042A
Authority: SU
Inventors: Юрий Николаевич Кузьмин; Симон Львович Мандельберг; Станислав Евгеньевич Семенов; Виктор Михайлович Пискунов; Марк Израилевич Гриншпун; Юрий Абрамович Медников; Иван Иванович Сергеев; Евгений Иванович Иванов
Original assignee: Ордена Ленина И Ордена Трудового Красного Знамени Институт Электросварки Им.Е.О.Патона
Priority date: 1984-07-31
Filing date: 1984-07-31
Publication date: 1986-12-07

Abstract

Изобретение относитс к производству труб, а более конкретно - к способам изготовлени сварных пр мошовных труб большего диаметра, и может найти применение в трубном производстве . Целью изобретени вл етс повышение качества сварки. По данному способу трубу изготавливают из двух полуобечаек, которые собирают мезкду собой и сваривают двум про. . дольными швами. Сварку производ т в следующей последовательности. Сначала на каждом стыке выполн ют сборочные швы с неполным проплавлением кромок. Затем дл устранени возникших сварочных деформаций, ухудшающих услови выполнени рабочих швов, трубу прав т путем пропускани ее через закрытый валковый калибр, периметр которого на 0,2-0,7% меньше . номинального наружного периметра труW бы. Дп обеспечени равномерного распределени деформации по периметру трубы правку производ т после снижени температуры металла в зоне стыков ниже 300 С.The invention relates to the manufacture of pipes, and more specifically to methods for producing welded straight-flow pipes of larger diameter, and may find application in pipe manufacturing. The aim of the invention is to improve the quality of welding. In this method, the pipe is made of two half-shells, which are collected mezkdu by themselves and welded two pro. . longitudinal seams. The welding is performed in the following sequence. First, assembly joints with incomplete penetration of the edges are made at each joint. Then, in order to eliminate the welding deformations that worsen the conditions of working joints, the pipe is right by passing it through a closed roll gauge, the perimeter of which is 0.2-0.7% smaller. The nominal outer perimeter would be. Dp to ensure uniform distribution of the deformation around the perimeter of the pipe, the correction is made after the temperature of the metal decreases in the area of the joints below 300 C.

Description

Изобретение относится к области производства труб, конкретнее к способам изготовления сварных прямошовных труб' большого диаметра.The invention relates to the field of pipe production, and more particularly to methods for manufacturing welded longitudinal seam pipes of large diameter.

Целью изобретения является повышение качества сварки.The aim of the invention is to improve the quality of welding.

Способ заключается в следующем.The method is as follows.

Две полуобечайки, сформованные из листов, собирают между собой и сваривают двумя наружными продольными швами с неполным проплавлением кромок. В результате сварочных деформаций от выполнения двух швов (наружных или внутренних) геометрическая форма трубы заметно искажается, что ухудшает условия выполнения внутренних рабочих швов.Two half-shells formed from sheets are assembled together and welded with two outer longitudinal seams with incomplete penetration of the edges. As a result of welding deformations from the execution of two seams (external or internal), the geometric shape of the pipe is noticeably distorted, which worsens the conditions for the execution of internal working seams.

Продольный изгиб трубных заготовок в зоне стыков кромок, вызванный сварочными деформациями, может привести к изменению пространственного положения сварочной ванны по длине трубной заготовки в процессе сварки внутренних рабочих швов.The longitudinal bending of pipe billets in the area of the joints of the edges caused by welding deformations can lead to a change in the spatial position of the weld pool along the length of the pipe billet during welding of internal welds.

Кроме того, продольный изгиб стьг ков и искажение профиля прикромочных эон трубных заготовок, по которым катятся ролики внутреннего сварочного аппарата, может вызывать изменение выпета электродов по дли!не шва. Изменение положения ванны расплавленного металла относительно горизонтальной плоскости и нарушение параметров процесса сварки, . вызываемые изменением вылета электродов, могут привести к существенному снижению качества внутренних рабочих швов, поэтому после выполнения наружных рабочих швов трубную заготовку пропускают через закрытый валковый калибр, периметр которого на 0,2-0,7% меньше номинального периметра трубы.In addition, the longitudinal bending of the stitches and the distortion of the profile of the edge-on-eon tube blanks along which the rollers of the internal welding machine roll can cause a change in the protrusion of the electrodes along the seam length. Changing the position of the molten metal bath relative to the horizontal plane and violation of the welding process parameters,. caused by a change in the electrode outreach, can lead to a significant decrease in the quality of internal working joints, therefore, after performing external working joints, the tube stock is passed through a closed roll gauge, the perimeter of which is 0.2-0.7% less than the nominal perimeter of the pipe.

В результате обжатия трубы по периметру происходит устранение сварочных деформаций, при этом для обеспечения равномерного распределения деформаций сжатия по периметру тру- , бы обжатия проводят после охлаждения металла в зоне стыков до температур ниже 300°С, при которых практически полностью восстанавливаются прочностные свойства металла.As a result of the compression of the pipe around the perimeter, welding deformations are eliminated, and in order to ensure uniform distribution of compression deformations along the perimeter of the pipe, compression is carried out after cooling the metal in the joint zone to temperatures below 300 ° C, at which the strength properties of the metal are almost completely restored.

, Периметр закрытого валкового калибра, через которой необходимо пропустить трубу, определяют из выражения где - периметр валкового калибра;The perimeter of the closed roll caliber through which the pipe must be passed is determined from the expression where is the perimeter of the roll caliber;

Р_т - номинальный наружный периметр трубы;R _t - nominal outer perimeter of the pipe;

ζ - относительное уменьшение периметра трубы в калибре, %.ζ is the relative decrease in the perimeter of the pipe in caliber,%.

Для современных трубных сталей, обладающих пределом текучести б_т = = 400 - 500 МПа, значение £ должно быть не менее 0,2% с тем, чтобы обеспечить деформацию металла трубы по всему периметру в пластической области. Продольный прогиб трубы по швам сопровождается изменением ее овальности на центральном и концевых участках (образование бочки, либо раструбов). Принудительное выравнивание овальности по длине трубы после сварки наружных рабочих швов приводит к уменьшению продольного прогиба по швам. Такого же эффекта, но в значительно меньшей степени, можно добиться и в случае обжатия трубы при £<0,2%. Изменение овальности произойдет в этом случае за счет местных пластических деформаций изгиба отдельных участков профиля трубы.For modern pipe steel having a yield point b _m = 400 - 500 MPa, the value of £ should be at least 0.2% in order to ensure deformation of the metal tube around the perimeter in the plastic region. The longitudinal deflection of the pipe at the seams is accompanied by a change in its ovality in the central and end sections (the formation of a barrel or sockets). Forced alignment of ovality along the length of the pipe after welding of the external working seams leads to a decrease in the longitudinal deflection at the seams. The same effect, but to a much lesser extent, can be achieved in the case of compression of the pipe at £ <0.2%. The change in ovality will occur in this case due to local plastic bending deformations of individual sections of the pipe profile.

В случае обжатия трубы в пластической области при £ £ 0,2% произойдет исправление местных искажений поперечного профиля трубы и дальнейшее выравнивание ее овальности по длине.In the case of compression of the pipe in the plastic region at £ £ 0.2%, local distortions of the transverse profile of the pipe will be corrected and its ovality will be further aligned along the length.

Наиболее полное выравнивание прогиба трубы по шву может быть осуществлено за счет пластического деформирования трубы в направлении продольной оси. Продольная пластическая деформация трубы вызовет перераспределение и сглаживание продольных напряжений от сварки, вызывающих прогиб трубы по шву. Учитывая, что коэффициент Пуассона для стали примерно равен 3,3, поперечная деформация, обеспечивающая продольную деформацию в пластической o6nagTH, должна составлять не менее 0,7%.The most complete alignment of the deflection of the pipe along the seam can be carried out due to plastic deformation of the pipe in the direction of the longitudinal axis. Longitudinal plastic deformation of the pipe will cause a redistribution and smoothing of longitudinal stresses from welding, causing the pipe to bend along the seam. Considering that the Poisson's ratio for steel is approximately equal to 3.3, the transverse deformation providing longitudinal deformation in plastic o6nagTH should be at least 0.7%.

Предлагаемым способом производили сварку труб диаметром 1420 мм с толщиной стенки 15,6 мм. Трубы пропускались по всей длине через закрытый валковый калибр сварочной клети сборочно-сварочного стана.The proposed method produced welding of pipes with a diameter of 1420 mm with a wall thickness of 15.6 mm. Pipes were passed along the entire length through a closed roll gauge of the welding stand of the assembly-welding mill.

Средняя величина наружного периметра труб составляла 4458 мм, а валко3 вый калибр настраивался на периметры 4451, 4445 и 4427 мм.The average value of the outer perimeter of the pipes was 4458 mm, and the roll caliber was adjusted to the perimeters 4451, 4445, and 4427 mm.

В первом случае относительно обжатие трубы в калибре £ составляло 0,15%. Средняя величина продольного 5 прогиба по двум шв’ам этой трубы ζ уменьшилась с 15 до 11 мм, профили прикромочных зон практически не изменились .In the first case, the relative compression of the pipe in caliber £ was 0.15%. The average value of the longitudinal 5 deflection along the two welds of this ζ pipe decreased from 15 to 11 mm, the profiles of the marginal zones practically did not change.

Во втором случае относительное об- Ю жатие трубы по периметру составило 0,3%. Местные искажения профиля (пе·^ регибы, участки пониженной кривизны) были выправлены,’ существенно повысилась стабильность профиля прикромочных зон трубы, за счет чего изменение вылета электродов при сварке рабочих внутренних швов уменьшилось бы с 10 до 4 мм. Средняя величина продольного прогиба по двум швам этой 20 трубы уменьшилось с 14 до 7 мм.In the second case, the relative compression of the pipe around the perimeter was 0.3%. Local profile distortions (kinks, sections of reduced curvature) were corrected, ’the profile stability of the edge zones of the pipe was significantly increased, due to which the change in the electrode outgrowth during welding of working internal seams would decrease from 10 to 4 mm. The average longitudinal deflection at the two seams of this 20 pipe decreased from 14 to 7 mm.

В третьем случае относительное обжатие трубы по периметру £ составило 0,7%. Средняя величина продольного прогиба по двум швам этой тру- 25 бы уменьшилась с 17 до 5 мм. Изменение вылета электродов внутреннего аппарата уменьшилось бы с 9 до 3 мм.In the third case, the relative compression of the pipe along the perimeter of £ was 0.7%. The average longitudinal deflection at the two seams of this pipe 25 would decrease from 17 to 5 mm. The change in the extension of the electrodes of the internal apparatus would decrease from 9 to 3 mm.

Обжатие трубы после сварки наружных рабочих швов позволяет уменьшить продольный прогиб трубы по швам, стабилизировать профиль прикромочных зон по длине трубы и за счет этого улучшить условия выполнения и качество внутренних рабочих швов, а в конечном счете качество и надежность в эксплуатации труб большого диаметра, применяемых при сооружении магистральных газо- и нефтепроводов.The compression of the pipe after welding of the external working joints allows to reduce the longitudinal deflection of the pipe along the joints, to stabilize the profile of the edge zones along the length of the pipe and thereby improve the working conditions and quality of the internal working joints, and ultimately the quality and operational reliability of large diameter pipes used for the construction of gas and oil pipelines.

Claims

The invention relates to the field of pipe production, more specifically to the production of welded large diameter welded straight pipes. The aim of the invention is to improve the quality of welding. The method is as follows. Two half-shells, formed from sheets, are assembled between themselves and welded with two external longitudinal seams with incomplete penetration of the edges. As a result of welding deformations from making two seams (external or internal), the geometric shape of the pipe is noticeably distorted, which worsens the conditions for performing internal working seams. Longitudinal bending of the billet in the area of the edge joints, caused by welding deformations, can lead to a change in the spatial position of the weld pool along the length of the billet during welding of internal working seams. In addition, the longitudinal bending of the joints and the distortion of the profile of the edge of the billet zones, along which the rollers of the internal welding apparatus are rolled, can cause the discharge of electrodes along the seam. Changing the position of the bath | molten metal relative to the horizontal plane and violation of the parameters of the welding process,. caused by a change in the emission of electrodes, can lead to a significant reduction in the quality of internal working joints; therefore, after making external working joints, the pipe billet is passed through a closed roll gauge, whose perimeter is 0.2-0.7% less than the nominal pipe perimeter. As a result of tube compression along the perimeter, welding deformations are eliminated, while for both livers a uniform distribution of compression deformations along the perimeter of the compression tube is carried out after cooling the metal in the joint zone to temperatures below 300 ° C, at which; the strength properties of the metal are almost completely restored. , The perimeter of a closed roll gauge, through which the pipe must be passed, is determined from the expression 0 p p k t 100 where PI is the perimeter of the roll gauge; R is the nominal outer perimeter of the pipe; - relative reduction of pipe perimeter in caliber,%. For modern pipe steels with a yield strength of 0 400 - 500 MPa, the value should be at least 0.2% in order to ensure the deformation of the metal of the pipe along the entire perimeter in the plastic region. The longitudinal deflection of the pipe along the seams is accompanied by a change in its ovality on the central and end sections (formation of a barrel or sockets). Forced alignment of ovality along the length of the pipe after welding external working seams leads to a decrease in longitudinal deflection along the seams. The same effect, but to a much lesser extent, can be achieved in the case of pipe compression at .0.2%. The change in ovality will occur in this case due to local plastic deformations of bending of individual sections of the pipe profile. In the case of pipe collapsing in the plastic area with S: 0.2%, local distortions of the cross section of the pipe will be corrected and its ovality will be evened out. The fullest alignment of the pipe deflection along the seam can be achieved by plastic deforming the pipe in the direction of the longitudinal axis. Longitudinal plastic deformation of the pipe will cause redistribution and smoothing of longitudinal stresses from welding, causing the pipe to sag along the seam. Considering that the Poisson's ratio / steel center ratio is approximately equal to 3.3, the lateral deformation, which provides longitudinal deformation in the plastic region, should be at least 0.7%. The proposed method produced welding of pipes with a diameter of 1420 mm with a wall thickness of 15.6 mm. The pipes were passed through the entire length through the closed roll gauge of the welding stand of the assembly-welding mill. The average external perimeter of the tubes was 4458 mm, and the roll gauge was adjusted to the perimeter 4451, 4445 and 4427 mm. In the first case, the relative compression of the pipe in caliber was 0.15%. The average value of the longitudinal deflection along the two joints of this pipe: decreased from 15 to 11 mm, the profiles of the near-edge zones practically did not change. In the second case, the relative pressure of the pipe around the perimeter was 0.3%. Local distortions of the profile (ne, areas of reduced curvature) were corrected, the profile stability significantly increased at the edge zones of the pipe, due to which the change in electrode overhang during welding of internal working welds would decrease from 10 to 4 mm. The average longitudinal deflection along the two joints of this pipe has decreased from 14 to 7 mm. In the third case, the relative compression of the pipe along the perimeter was 0.7%. The average value of the longitudinal deflection along two pgeas of this pipe decreased from 17 to 5 mm. The change in the overhang of the electrodes of the inner apparatus would decrease from 9 to 3 mm. Compressing the pipe after welding the outer working joints reduces the longitudinal deflection of the pipe along the seams, stabilizes the profile of the edge of the edge of the length of the pipe and thereby improves the condition and quality of the inner working seams. Ultimately, the quality and reliability in operation of large-diameter pipes used in the construction of gas and oil trunk pipelines. The invention The method of manufacturing straight conduit pipes, in which two half-shells are assembled between each other, is performed by external seams, and then internal working seams, characterized in that, in order to improve the quality of the pipe, after the external seams are completed, the pipe in the joint zone is cooled to a temperature below 300 C and pass it through the closed roll gauge, the perimeter of which is 0.2-0.7% less than the nominal outer perimeter of the pipe.