SU747682A1

SU747682A1 - Titanium anode restoring method

Info

Publication number: SU747682A1
Application number: SU782596496A
Authority: SU
Inventors: Вадим Ипполитович Дюмулен; Анатолий Филиппович Золотов; Владислав Васильевич Рощин; Эдуард Федорович Рябов; Владимир Львович Хейфец; Илья Самуилович Шапиро
Original assignee: Предприятие П/Я В-2287
Priority date: 1978-03-29
Filing date: 1978-03-29
Publication date: 1980-07-15

Description

Изобретение относится к области электрохимических производств, в частности, к монтажу электролизеров, точнее к регенерации титановых j анодов.The invention relates to the field of electrochemical production, in particular, to the installation of electrolyzers, more specifically to the regeneration of titanium j anodes.

Известен способ соединения анодов с токоподводами электролизеров при помощи сварки [1] .There is a method of connecting anodes with current leads of electrolytic cells by welding [1].

Недостатком этого способа являет- jq ся то,что в нем не решена задача отделения анодов для их регенерации — восстановления окисно-рутениевого покрытия и последующей приварки.The disadvantage of this method is that it does not solve the problem of separating the anodes for their regeneration — restoration of the oxide-ruthenium coating and subsequent welding.

Известен способ дуговой обработки, при котором кромки, полученные с помощью плазменной резки, сваривают в дальнейшем без всякой дополнительной обработки [2] .A known method of arc processing, in which the edges obtained using plasma cutting are welded in the future without any additional processing [2].

Однако, при использовании извест- 20 ного способа для обработки таких химически активных металлов, как титан, в металле шва, особенно в корневой части, возникают трещины. Это связано с тем, что при резке, время существования ванны расплавленного металла в этой части полости реза является наибольшим й оплавленный слой металла, остающийся на кромке реза, содержит вследствие взаимодействия с окружающей атмосферой наибольшее количество таких газов как азот и кислород. Переход этих газов в металл шва при последующей сварке обуславливает появление трещин в этой части сварного соединения. Кроме того, известный способ не обеспечивает сохранения поперечного относительно линии реза размера анода при его плазменной резке и последующей сварке по месту реза. Эти недостатки препятствуют применению сварного соединения титановых анодов, имеющих активное (окисно-рутениевое) покрытие рабочей части.However, when using the known method for processing chemically active metals such as titanium, cracks appear in the weld metal, especially in the root part. This is due to the fact that during cutting, the lifetime of the molten metal bath in this part of the cut cavity is the largest and the melted metal layer remaining on the cut edge contains, due to interaction with the surrounding atmosphere, the largest amount of such gases as nitrogen and oxygen. The transition of these gases into the weld metal during subsequent welding causes the appearance of cracks in this part of the welded joint. In addition, the known method does not ensure the conservation of the transverse relative to the cut line size of the anode during its plasma cutting and subsequent welding at the place of cut. These disadvantages impede the use of welded joints of titanium anodes having an active (oxide-ruthenium) coating of the working part.

В связи с необходимостью периодического отделения анодов для ре- . генерации активного покрытия, их подсоединение производится в настоящее время титановым крепежом, что вызывает повышенный расход электроэнергии на потери в контактах, а также расход крепежа и дополнительный расход 25 материала анодов на нахлестку.Due to the need for periodic separation of the anodes for re-. generation of the active coating, their connection is currently being carried out with titanium fasteners, which causes an increased energy consumption for losses in the contacts, as well as the consumption of fasteners and an additional consumption of 25 anode material for lapping.

Известен способ восстановления пластинчатого титанового анода,при котором отделяют анод от токоподвода, регенерируют его покрытие и при30 соединяют анод к токоподводу .A known method of restoring a plate titanium anode, in which the anode is separated from the current lead, regenerate its coating and at 30 connect the anode to the current lead.

Недостатком известного способа является повышенное контактное сопротивление, которое составляет более 10 мв. При'этом дополнительный расход электроэнергии составляет, наприр мер, для электролизе'ра на нагрузку 100 ка — 8500 квт час/год и для электролизера на нагрузку 50 ка — 42-50 квт/час/год.The disadvantage of this method is the increased contact resistance, which is more than 10 mV. In this case, the additional energy consumption is, for example, for an electrolyzer for a load of 100 ka - 8500 kWh / year and for an electrolyzer for a load of 50 ka - 42-50 kW / h / year.

Цель изобретения - улучшение качества восстановления анода путем уменьшения электросопротивления и исключения уменьшения длины анода.The purpose of the invention is to improve the quality of restoration of the anode by reducing electrical resistance and eliminating the reduction of the length of the anode.

Указанная цель достигается тем, что анод отделяют резкой сжатой дугой, которую ориентируют к поверх-, ности анода под углом не равным 9 0*’ после регенерации стыкуют разрезанные- части острыми кромками й производят сварку.This goal is achieved by the fact that the anode is separated by a sharp compressed arc, which is oriented to the surface of the anode at an angle not equal to 9 0 * ’after regeneration, the cut parts are joined, the sharp edges and welding are performed.

В случае наличия механической обработки кромок, резку осуществляют так, чтобы угол наклона плоскости, в которой лежат острые кромки к поверхности обрабатываемого анода составлял 65-85°.In the case of mechanical processing of the edges, the cutting is carried out so that the angle of inclination of the plane in which the sharp edges lie to the surface of the processed anode is 65-85 °.

Величина угла наклона с(_п плоскости,^ проходящей через острые кромки к обрабатываемой поверхности, определяется соотношением между толщиной разрезаемого анода и припуском на механическую обработку, так что tgiA_n=B/26 , где В — толщина, разрезаемого анода, 8 — припуск на механическую обработку.The angle of inclination c ( _{n of the} plane passing through sharp edges to the surface to be machined is determined by the ratio between the thickness of the cut anode and the machining allowance, so that tgiA _n = B / 26, where B is the thickness of the cut anode, 8 is the allowance for machining.

При изменении толщины анода от 2 до 10 мм и припуска на механическую обработку от 0,5- до 2 мм, величина находится в пределах от 2 до 10 и , соответственно, в пределах от 65 до 85°When changing the thickness of the anode from 2 to 10 mm and the allowance for machining from 0.5 to 2 mm, the value is in the range from 2 to 10 and, accordingly, in the range from 65 to 85 °

На фиг. 1 и 2 показаны соответственно схемы процессов плазменной резки аргоно-дуговой сварки по кромкам, выполненным плазменной резкой.In FIG. Figures 1 and 2 respectively show diagrams of the processes of plasma cutting of argon-arc welding along the edges made by plasma cutting.

На схеме приведены плазмотрон 1. для резки, плазменная дуга 2, токсподвод 3, анод 4, близкорасположенные к плазмотрону поверхности токеподвода 5 и анода 6, дальние от плазмотрона поверхности токоподвода 7 и анода 8, валик 9 наплавленного металла, формирующий корневой шов,горелка 10 для газодуговой сварки,сварочная дуга 11,сварной шов 12,выполненный по кромкам,подготовленным плазменной резкой,толщина Δ*, оплавленного слоя металла на близкорасположенных к плазмотрону кромках реза, толщина Ag оплавленного слоя металла на дальних от плазмотрона кромках реза, угол ориентаций плазменной дуги при резке, угол разделки кромок, получаемой плазменной резкой.The diagram shows the plasma torch 1. for cutting, a plasma arc 2, current lead 3, anode 4, the surfaces of the current lead 5 and anode 6 located close to the plasma torch, distant from the plasma torch of the surface of the current lead 7 and anode 8, the weld metal roller 9 forming the root seam, burner 10 for gas-arc welding, welding arc 11, weld 12 made along the edges prepared by plasma cutting, thickness Δ *, molten metal layer at the cutting edges close to the plasma torch, thickness Ag of the molten metal layer at the edges farthest from the plasma torch ah cut, the angle of orientation of the plasma arc during cutting, the angle of cutting edges obtained by plasma cutting.

Способ осуществляется следующим образом.The method is as follows.

Плазмотрон 1 перемещают относительно обрабатываемого изделия. Горение в полости реза плазменной ду ги 2 обеспечивает отделение анода 4 от токоподвода 3. Угол ориентации плазменной дуги при резке выбирают исходя из требований формы разделки кромок и сохранения длины анода., nfm этом, а,-Толщина оплавленного слоя металла на кромках реза имеет наименьшую величину у блиэрасположенных к плазмотрону поверхностей 5 и 6 и, соответственно, наибольшую величину у дальних от плазмотрона поверхностей 7 и 8. Аналогично изменяется и количество газов (азота и кислорода), растворенных в оплавленном при резке металла. Наличие газонасыщенного слоя на кромках реза обусловлено переходом газов из плазмообразующей среды,а также их подсосом из окружающей атмосферы. При последующей сварке эти газы из ранее оплавленного слоя переходят в металл шва, что обуславливает появление в нем трещин. Такая картина особенно характерна для корневого шва, имеющего наибольшие зоны термического влияния на обеих кромках и максимальный размер газонасыщенного слоя. Поэтому отрезанный для регенерации анод перед последующей сваркой стыкуют острыми кромками. При этом дальняя от плазмотрона поверхность токоподвода 7 становится близрасположенной к сварочной горелке 10. За счет такого приема происходит выравнивание величины газонасыщенного слоя по высоте шва и уменьшение количества газов, переходящих в корневой шов из ранее оплавленного слоя. Поэтому в валике 9, который находится в неблагоприятных условиях из-за того, что здесь доля участия присадочного металла в формировании шва 12 наимень-. шая, трещины практически не возникают. При необходимости повторного отделения анода резку производят с обратной стороны сварного шва 12.The plasma torch 1 is moved relative to the workpiece. Burning in the cutting cavity of the plasma arc 2 ensures the separation of the anode 4 from the current supply 3. The angle of orientation of the plasma arc during cutting is chosen based on the requirements of the shape of the cutting edges and preserving the length of the anode. the value of surfaces 5 and 6 located near the plasmatron and, accordingly, the largest value of surfaces 7 and 8 distant from the plasma torch. The amount of gases (nitrogen and oxygen) dissolved in the metal melted during cutting also changes. The presence of a gas-saturated layer at the edges of the cut is due to the transition of gases from the plasma-forming medium, as well as their suction from the surrounding atmosphere. In subsequent welding, these gases from the previously melted layer pass into the weld metal, which causes the appearance of cracks in it. This picture is especially characteristic of the root joint, which has the largest heat-affected zones at both edges and the maximum size of the gas-saturated layer. Therefore, the anode cut off for regeneration is joined with sharp edges before subsequent welding. In this case, the surface of the current lead 7, which is farthest from the plasma torch, becomes close to the welding torch 10. Due to this technique, the size of the gas-saturated layer is aligned along the height of the seam and the amount of gases passing to the root seam from the previously melted layer is reduced. Therefore, in the roller 9, which is in adverse conditions due to the fact that here the share of the filler metal in the formation of the weld 12 is the smallest. jointing, cracks practically do not occur. If necessary, re-separation of the anode, cutting is performed on the back of the weld 12.

Примером выполнения предлагаемого способа явилась плазменно-дуговая резка и последующая приварка анодов электролизера на 15 ка.An example of the implementation of the proposed method was plasma-arc cutting and subsequent welding of the electrodes of the electrolyzer to 15 ka.

Отрезка производилась по токоподводящей части анодов, представляющей собой титановый (ВТ1-0; лист толщиной 4 мм и длиной 250 мм. В качестве плазмообраэующей среды использовался технический азст.The section was made along the current-supplying part of the anodes, which is titanium (VT1-0; a sheet 4 mm thick and 250 mm long. Technical plasma was used as a plasma-forming medium.

Режим резки: ток - 220 а; расход газа — 3,0 сек; скорость ^ез ки — 2,U м/мин.Cutting mode: current - 220 A; gas consumption - 3.0 sec; speed ^ ezki - 2, U m / min.

Сварка производилась по месту реза в среде аргона на токе 170 а, и напряжении 40 В.Welding was carried out at the place of cut in an argon medium at a current of 170 A and a voltage of 40 V.

Было обработано три группы анодов по 10 штук в каждой.·Three groups of anodes of 10 pieces each were processed. ·

При резке первой группы анодов плазмотрон устанавливался так,чтобы острые кромки реза лежали в плоскос ти перпендикулярной поверхности обрабатываемого анода. При этом угол ориентации плазменной дуги е</·- 60° Резка второй группы анодов проводилась так, чтобы острые кромки лежали в плоскости наклонной в сторону тупых кромок д величиной угла наклона 70° при угле ориентации плаз.менной дуги = 45°.When cutting the first group of anodes, the plasmatron was mounted so that the sharp edges of the cut lay in the plane perpendicular to the surface of the treated anode. In this case, the angle of orientation of the plasma arc e </ · - 60 ° The cutting of the second group of anodes was carried out so that the sharp edges lay in the plane inclined towards the obtuse edges with a tilt angle of 70 ° at an angle of orientation of the plasma arc = 45 °.

Приварка первой и второй групп анодов к токоподводам производилась при стыковке острыми кромками, причем кромки анодов второй группы подвергались предварительной механической обработке.Welding of the first and second groups of anodes to current leads was carried out when joined by sharp edges, and the edges of the anodes of the second group were subjected to preliminary mechanical processing.

Третья, контрольная, группа анодов отрезалась без образования острых кромок на противоположных плоскостях обрабатываемого анода при расположении осиплазменной дуги перпендикулярно обрабатываемой поверхности, а их приварка проводилась с сохранением взаимного расположения кромок реза.The third, control, group of anodes was cut off without the formation of sharp edges on opposite planes of the processed anode with an osplasma arc perpendicular to the surface being machined, and their welding was carried out while maintaining the relative position of the edges of the cut.

Аноды с восстановленным покрытием были установлены в электролизер, срок работы которого к настоящему времени составил более года. За этот период проведено два обследования состояния места реэа-сварки и его электросопротивления.The anodes with the reconditioned coating were installed in the electrolyzer, the operating life of which to date has been more than a year. During this period, two surveys of the state of the re-welding site and its electrical resistance were carried out.

Проведенные замеры показали, что электросопротивление токоподводов двух первых.групп анодов составляет 5 мв, что не превышает величины электросопротивления основного металла и на 10-15 мв меньше электросопротивления болтового контактного соединения. Трещин в швах, .выполненных по предлагаемому способу в 1 и 2 группах анодов не обнаружено. В сварных швах в анодах контрольной группы, выполненных обычным способом, обнаружены трещины до 15 мм, а также последующая коррозия дефектных сварных швов. Электросопротивление этих участков составляет 15-20 мв, что на 10-15 мв больше величины электросопротивления для первых двух групп анодов и для болтового контактного соединения.The measurements showed that the electrical resistance of the current leads of the first two groups of anodes is 5 mV, which does not exceed the value of the electrical resistance of the base metal and is 10-15 mV less than the electrical resistance of the bolt contact connection. Cracks in the seams made by the proposed method in groups 1 and 2 of the anodes were not found. In the welds in the anodes of the control group, made in the usual way, cracks up to 15 mm were detected, as well as subsequent corrosion of the defective welds. The electrical resistance of these sections is 15–20 mV, which is 10–15 mV higher than the electrical resistance for the first two groups of anodes and for the bolt contact connection.

Claims

The invention relates to the field of electrochemical production, in particular, to the installation of electrolyzers, more specifically to the regeneration of titanium anodes. There is a known method of connecting anodo with current leads of electrolyzers by welding l. The disadvantage of this method is that it does not solve the problem of dividing the anodes for their regeneration and the reduction of the oxide-ruthenium coating and subsequent welding. There is a known method of arc treatment, in which the edges obtained by plasma cutting are subsequently welded without any additional processing 2. However, when using a known method for treating such chemically active metals as titanium in the weld metal, especially in the root part, cracks occur. This is due to the fact that during cutting, the time of existence of the molten metal bath in this part of the cutting cavity is the largest and the melted metal layer remaining on the cutting edge contains, due to interaction with the surrounding atmosphere, the largest amount of gases such as nitrogen and oxygen. The transition of these gases to the weld metal during subsequent welding causes the appearance of cracks in this part of the welded joint. In addition, the known method does not ensure that the anode pa3Viepa is transverse with respect to the cutting line during its plasma cutting and subsequent welding at the place of cutting. These disadvantages prevent the use of a welded joint of titanium anodes with an active (ruthenium oxide) coating of the working part. Due to the need to periodically separate anodes for pe-. the generation of active coating, their connection is currently being made with titanium fasteners, which causes increased power consumption for contact losses, as well as fastener consumption and additional anode material consumption for overlap. A known method of restoring a plate titanium anode, in which the anode is separated from the current lead, its coating is regenerated and the anode is attached to the current lead 3. The disadvantage of this method is the increased contact resistance, which is more than 10 MB. In this case, the additional electric power consumption is, for example, for an electrolytic cell at a load of 100 ka - 8500 cat / h / year and for an electrolytic cell at a load of 50 ka 42-50 KW / h / year. The purpose of the invention is to improve the quality of anode recovery by reducing the electrical resistance and eliminating the decrease in the anode length. This goal is achieved by separating the anode with a sharp, compressed arc, which the reference point to the anode surface at an angle not equal to 90 after regeneration join the cut: parts with sharp edges and weld. In the case of the presence of machining of edges, the cutting is carried out so that the angle of inclination of the plane in which the sharp edges lie to the surface of the anode being machined is 65-854 The angle of inclination c,., Plane ,; passing through the sharp edges to the surface to be treated, the ratio between the thickness of the anode being cut and the machining allowance is determined, so that where B is the thickness of the anode being cut, & - allowance for machining. When the anode thickness changes from 2 to: 10 mm and the machining allowance is from 0.5 to 2 mm, the value is in the range from 2 to 10; and L, respectively, in the range from 65 to 85 °: FIG. . Figures 1 and 2 show, respectively, the diagrams of the processes of a plasma river of argon-arc welding along the edges made by plasma cutting. The diagram shows a plasma torch 1. for cutting, a plasma arc 2, a current supply 3, an anode 4, surfaces of the current lead 5 and anode 6 closely spaced to the plasmotron, furthest away from the surface of the electrical lead 7 and anode 8, plasma 9 of the weld metal, forming root weld, bit 10 for gas arc welding, welding on arc 11, weld 12, made along the edges prepared by plasma cutting, thickness d-i of the melted metal layer on the cutting edge of the plasmotron adjacent to the tromdin A of the melted metal layer far to the plasma torch chrome Kah of the cut, the angle from the orientation of the plasma arc during cutting, the angle from the cutting edge, obtained by plasma cutting. The method is carried out in a skinny manner. Plasma torch 1 is moved relative to the workpiece, Gorey in the cutting cavity of the plasma arc 2 provides separation of the anode 4 from the electrical power supply 3. The orientation angle of the plasma arc during cutting is selected based on the requirements of the shape of the edge and preserving the length of the anode. The thickness of the melted metal layer at the edges of the cut has the smallest zelichina of the surfaces 5 and 6 nearby to the plasma torch and, accordingly, the largest value of the surfaces 7 and 8 far from the plasma torch. Similarly, the number scratch (nitrogen and oxygen) dissolved in the sintered metal at the sharp ke. The presence of a gas-saturated layer at the edges of the cut is due to the transition of gases from the plasma-forming medium, as well as their leakage from the surrounding atmosphere. During subsequent welding, these gases are transferred from the previously melted layer to the weld metal, which causes the appearance of cracks in it. This picture is especially characteristic of the root joint, which has the largest heat-affected zones on both edges and the maximum size of the gas-saturated layer. Therefore, the anode, which is cut off for regeneration, before-subsequent welding, is joined by sharp edges. At the same time, the surface of the electrical power supply 7 far from the plasmatron becomes close to the welding torch 10. Due to this technique, the gas-saturated layer is equalized with the weld height and the amount of gases passing into the root weld is reduced from the previously melted layer. Therefore, in the roller 9, which is in adverse conditions due to the fact that here the fraction of the filler metal in the formation of the seam 12 is minimal, there are practically no cracks. If it is necessary to separate the anode again, the cutting is performed on the back side of the weld 12. An example of the implementation of the proposed YaB5 method; plasma arc cutting and subsequent welding of the anode electrolyzer by 15 na. The section was cut by the current-carrying part of the anodes, which is titanium ( BTl-O) 4 mm thick sheet and a length of 250 liters. Technical nitrogen was used as the plasma-forming medium. Cutting mode: current - 220 a; gas consumption - 3, cutting speed 2.0 m / min. Welding was performed at the cut point in argon at a current of 170 a. and a voltage of 40 V. Three groups of anodes, 10 pieces each, were processed. The cutting of the first group of anodes of the chasmotron was set so that sharp KJpoMKH cuts lay in the plane of the perpendicular surface of the anode to be machined. In this case, the orientation angle of the plasma arc - BS Cutting of the second group of anodes of the head section so that the sharp edges lie in the plane inclined towards the blunt edges with a slope of 70 at the orientation angle of the arc arc cX, 45 I welded the first and second groups of anodes to the current leads when joining with sharp edges, and the edges of the anodes of the second group were subjected to preliminary mechanical processing. The third, troll, anode group was cut off without the formation of sharp edges on the opposite planes of the anode to be machined when the ojplasma arc was perpened, and the machined surface was welded with the cut edges retained. The anodes with a reduced coating were installed in the electrolyzer, whose operation has now amounted to more than a year. During this period, two surveys were carried out on the state of the cut-welding site and its electrical resistance. The measurements showed that the electrical resistance of the two first anode power leads of the anodes is 5 MBf, which does not exceed the electrical resistance of the base metal and is 10-15 MB lower than the electrical resistance of the bolted contact connection. Cracks in the seams,. Performed by the proposed method in 1 and 2 groups of anodes is not detected. In the welds in the anodes of the control group, made in the usual way, cracks up to 15 mi were detected, as well as subsequent corrosion of defective welds. The electrical resistance of these sections is 15-20 mV, which is 10-15 MB higher than the electrical resistance for the first two groups of anodes and for the bolted connection. Claims A method for restoring a titanium anode, in which an anode is separated from a cold lead, regenerates its coating and attaches an anode to a current lead, characterized in that, in order to improve the quality of anode recovery by reducing the resistivity and eliminating reducing the length of the anode, the anode is separated by sharply compressed an arc that is oriented to the anode surface at an angle not equal to 90 ° after regeneration joins the cut parts with sharp edges and welds. Sources of (l) Media taken into account during the examination 1. Swedish Patent 357890, cl. O1 C 3/04, 1968.

2.Yapiro I.S. The influence of the method of preparation of edges on the corrosion resistance of welded joints made of steel Х18Н10Т, Chemical and petroleum engineering, 1973, 10, p.20-22,

3. US patent I3563,878, class, 204-256, 1968,