SU789255A1

SU789255A1 - Ultrasonic welding and soldering method

Info

Publication number: SU789255A1
Application number: SU792729226A
Authority: SU
Inventors: Николай Михайлович Тарасов; Всеволод Михайлович Тулин; Сергей Владимирович Филипковский
Original assignee: Харьковский авиационный институт им.Н.Е.Жуковского
Priority date: 1979-02-26
Filing date: 1979-02-26
Publication date: 1980-12-23

Description

Изобретение относится к области электродуговой сварки и пайки в среде защитного . газа, а более конкретно к способам управления переносом электродного металла в виде одной капли с помощью импульсной газодинамической силы, и мо- ⁵жет быть использовано при производстве изделий, требующих нанесения дозированных небольших количеств расплавленного металла.The invention relates to the field of electric arc welding and soldering in a protective environment. gas, and more particularly to control methods for transferring the metal electrode to form a droplet by the pulsed gas-dynamic forces, and MO ⁵ Jet be used in the manufacture of products requiring the application dosage of small amounts of molten metal.

Известен способ, согласно по которому управляющее воздействие газа создается путем периодически перемещающегося вдоль оси электрода фокуса газового потока И·A known method according to which the control action of the gas is created by periodically moving along the axis of the electrode focus of the gas stream And

Однако применение этого способа при сварке и пайке одиночной каплей ведет к неэкономичному расходу газа, поскольку фокусирующий газ истекает с повышенным расходом в течение всего цикла свар-_ики. Кроме того, при большом расходе газа уносится значительная часть тепла электрической дуги, что требует увеличения тока дуги.However, the application of this method in welding and soldering with a single drop leads to uneconomical gas consumption, since the focusing gas expires with an increased flow rate during the entire welding _and welding cycle. In addition, with a large gas flow rate, a significant part of the heat of the electric arc is carried away, which requires an increase in the arc current.

Наиболее близким по технической сущности и достигаемому эффекту к предложенному является способ сварки, заключающийся в подаче к плавящемуся концу электрода импульсов газового потока с определенной частотой из пульсатора. Этот способ может применяться при управлении мелкокапельным переносом при сварке и пайке одиночной каплей И- .The closest in technical essence and the achieved effect to the proposed one is the welding method, which consists in supplying to the melting end of the electrode pulses of a gas stream with a certain frequency from the pulsator. This method can be used in controlling droplet transfer during welding and soldering with a single drop of And.

Однако применение этого способа при электродуговой сварке и пайке одиночной каплей также ведет к повышенному расходу импульсообразующего газа и повышенному току дуги. Это обусловлено тем, что в данном способе отключение дуги и открытие пульсатора не синхронизированы таким образом, чтобы дуга отключалась в тот момент, когда скорость газа вокруг открываемой капли достигнет максимальной величины. В результате скорость газа вокруг капли на конце электрода может достигнуть максимума, либо когда капля еще не сформировалась, либо через некоторое время после того как выключится электрическая дуга. Вследствие этого открывается капля недостаточной массы (кроме того она разбрыз гивается, так как в это время еще горит дуга), или капля расплавленного металла на конце электрода успевает остыть и, следовательно, для отрыва капли требуется большая ее начальная температура и большая скорость газа, гое есть необходимо увеличивать ток дуги и расход газа.However, the application of this method for electric arc welding and soldering with a single drop also leads to an increased consumption of pulse-forming gas and an increased arc current. This is due to the fact that in this method the arc switching off and the pulsator opening are not synchronized so that the arc is switched off at the moment when the gas velocity around the drop being opened reaches its maximum value. As a result, the gas velocity around the droplet at the end of the electrode can reach a maximum, either when the droplet has not yet formed, or some time after the electric arc turns off. As a result, a drop of insufficient mass opens (in addition, it sprays, because an arc is still burning at that time), or a drop of molten metal at the end of the electrode has time to cool down and, therefore, a large initial temperature and a high gas velocity are required to detach the drop There is a need to increase the arc current and gas flow.

Цель изобретения - улучшение качества и повышение экономичности процесса свар сила; Т - время запаздывания действия максимальной газодинамической силы на каплю по отношению к открытию пульсатора.The purpose of the invention is to improve the quality and increase the efficiency of the process of weld strength; T is the delay time of the action of the maximum gas-dynamic force per drop with respect to the opening of the pulsator.

Для того, чтобы газодинамическая си- ла, действующая на каплю, была максимальной в момент ее максимальной температуры, надо открывать пульсатор раньше, чем отключать электрическую дугу <0 на то же время , за которое газодинамическая сила возрастет до максимальной величины. Время запаздывания f ки путем устранения остывания капли и перегрева изделия, уменьшения расхода импульсообразующего газа и электроэнер- 15 гии.In order for the gas-dynamic force acting on the droplet to be maximum at the moment of its maximum temperature, it is necessary to open the pulsator before disconnecting the electric arc <0 at the same time, during which the gas-dynamic force will increase to the maximum value. The delay time f ki by eliminating the cooling of the droplet and overheating of the product, reducing the consumption of pulse-forming gas and electricity 15.

Поставленная цель достигается тем, что в данном способе подачу импульса газа включают раньше, чем отключают электрическую дугу на время, за которое 20 газодинамическая сила, действующая на каплю, достигает максимальной величины. Запаздывание максимума газодинамической силы по отношению к открытию пульсатора происходит потому, что в канале и сопле, 25 по которым газ проходит от пульсатора к капле на конце электрода, находится газу который разгоняется газом, выходящим из пульсатора за определенное время. Именно за это время скорость газа вок рут капли и следовательно, газодинамическая сила, действующая на каплю, достигает максимальной величины. Такая синхронизация открытия пульсатора и отключения дуги- обеспечивает отключение элек- . трической дуги и тог момент, когда скорость газа вокруг капли на конце электрода достигнет максимальной величины. В этом случае газодинамическая сила, дейст-j вующая нак каплю, будет максимальной, когда температура капли будет максимальной, т.е. когда силы поверхностного натяжения, удерживающие каплю на электроде, будут минимальными. Эго позволит снизить скорость газа в импульсе и нагрев капли, т.е, уменьшить расход газа и ток электрической дуги.This goal is achieved by the fact that in this method, the gas pulse is turned on before the arc is turned off for a time during which the 20 gas-dynamic force acting on the drop reaches its maximum value. The delay in the maximum gas-dynamic force with respect to the opening of the pulsator occurs because in the channel and nozzle 25 through which the gas passes from the pulsator to the droplet at the end of the electrode, there is gas which is accelerated by the gas leaving the pulsator in a certain time. It is during this time that the gas velocity revolves around the droplet and, consequently, the gas-dynamic force acting on the droplet reaches its maximum value. This synchronization of the opening of the pulsator and the disconnection of the arc-provides shutdown elek-. arc and then the moment when the gas velocity around the droplet at the end of the electrode reaches its maximum value. In this case, the gas-dynamic force acting on the drop will be maximum when the temperature of the drop is maximum, i.e. when the surface tension forces holding the drop on the electrode are minimal. The ego will reduce the gas velocity in the pulse and the heating of the droplet, that is, reduce gas consumption and the electric arc current.

На чертеже изображена диаграмма параметров процесса элекгродуговой сварки с предлагаемой синхронизацией.The drawing shows a diagram of the parameters of the electric arc welding process with the proposed synchronization.

На диаграмме обозначено: t -время;The diagram indicates: t-time;

Т -температура капли металла; J -ток электрической дуги; и^_с - напряжение управляющее обмоткой контактора силового при выключении тока ayrnj -напряжение, управляющее устройством, открывающим пульсатор, например, обмоткой элекгропневматического клапана; Р* -уп- . равняющая импульсная газодинамическая определяется экспериментально и выдерживается блоком управления оборудования для пайки или сварки.T is the temperature of a drop of metal; J is the current of the electric arc; and ^ _c is the voltage controlling the winding of the power contactor when the current is turned off; ayrnj is the voltage controlling the device that opens the pulsator, for example, the winding of the electro-pneumatic valve; P * -up-. equalizing gas-dynamic pulse is determined experimentally and maintained by the control unit of equipment for soldering or welding.

Пример. Проводится наплавка каплями меди массой'80 кг, диаметр электрода 1 мм. Ээектрическая дуга плавит электродную проволоку и образует каплю расплавленного металла. Когда капля приобретает определенный размер и массу, включается' электропневмагический клапан, открывающий пульсатор. Когда скорость газа около капли на конце электрода приближается к максимальной, электрическая дуга отключается и капля отрывается газодинамической силой потока газа, направляющегося на каплю соплом. Время , запаздывания в применявшейся горелке равно 0,1 с. В процессе контролируется ток электрической дуги и давление газа в пульсаторе, необходимые для отрыва капли расплавленного металла от электрода.Example. Surfacing is carried out with drops of copper weighing 80 kg, the diameter of the electrode is 1 mm. The electric arc melts the electrode wire and forms a drop of molten metal. When the drop acquires a certain size and mass, an electro-pneumatic valve is turned on, which opens the pulsator. When the gas velocity near the droplet at the end of the electrode approaches the maximum, the electric arc is turned off and the droplet is torn off by the gas-dynamic force of the gas flow directed to the droplet by the nozzle. The delay time in the burner used is 0.1 s. In the process, the electric arc current and the gas pressure in the pulsator are controlled to remove a drop of molten metal from the electrode.

Для сравнения те же параметры определены при проведении процесса наплавки без предлагаемой синхронизации, когда электрическая дуга отключается одновременно с открытием пульсатора. Данные сведены в таблицу.For comparison, the same parameters are determined during the surfacing process without the proposed synchronization, when the electric arc is switched off simultaneously with the opening of the pulsator. The data are tabulated.

Условия наплавки Surfacing conditions Время запаздывания,, 0 Delay time ,, 0 Ток дуги, А Arc current A -Давление газа в пульсато-^ ре, кг/см^д -Pressure gas in pulsato- ^ D, kg / ^d cm С предлагаемой син- 0,1 With the proposed syn 0.1 15 fifteen 0,2 0.2 хронизацией chronization Без предпа- Without assumptions гаемой синхронизации 0 Pulse Sync 0 28 28 0,5 0.5

Если разность времен срабатывания силового'контактора, отключающего электрическую дугу, и электроклапана, отрывающего пульсатор, существенна, то ее тоже следует учитывать при синхрониза5 ции процесса. В приведенном примере эте разность несущественна и не учитывает- ; ся.If the difference between the response times of the power contactor, which disconnects the electric arc, and the electrovalve, tearing off the pulsator, is significant, then it should also be taken into account when synchronizing the process. In the above example, this difference is not significant and does not take into account; Xia.

Экономическая эффективность предлагаемого способа определяется следующим. ₅Время, за которое газодинамическая сила, действующая на каплю на конце электрода, возрастает до максимума, составляет 0,1-0,2 с. В результате того, что в применяемых для таких способов ю горелках с электродом соприкасается массивный токоподводящий мундштук, теплоотвод от электрода и капли в мундштук относительно велик, и за указанные время капля в зависимости от массы и величины и нагрева остывает на несколько десятков градусов. Так как поверхностное натяжение у металлов зависит от температуры, то дри указанном охлаждении капли металла сила, удерживающая ее на конце электрода, увеличится в несколько раз, т.е. нужно в несколько раз увеличить газодинамическую силу, необходимую для * отрыва капли от электрода. Применение предлагаемого способа позволит отрывать 25 не успевшую остыть каплю импульсной газодинамической силой в несколько раз меньшей, чем до применения предлагаемого способа, т.е. снизить расход импульсообразующего газа в несколько раз. Кро~з₀ме того, так как при данном способе требуется меньший разогрев капли, то будет меньше нагреваться и изделие, на которое наплавляется капля, что улучшит качество изделий, потому что для них перегрев нежелателен, например, для плавких предохранителей. Улучшается также точность дозирования металла и сдавленный конец электрода всегда имеет правильную геометрическую форму, что играет определенную роль при повторном возбуждении дуги.The economic efficiency of the proposed method is determined by the following. _{5 The} time during which the gas-dynamic force acting on a drop at the end of the electrode increases to a maximum is 0.1-0.2 s. As a result of the fact that in the burners used for such methods, a massive current-carrying mouthpiece is in contact with the electrode, the heat removal from the electrode and the droplet into the mouthpiece is relatively large, and over the indicated time the drop cools down by several tens of degrees depending on mass and size and heating. Since the surface tension of metals depends on temperature, for the indicated cooling of a drop of metal, the force holding it at the end of the electrode will increase several times, i.e. it is necessary to increase several times the gas-dynamic force necessary for * separation of the droplet from the electrode. The application of the proposed method will allow you to tear off 25 not had time to cool a drop of pulsed gas-dynamic force several times less than before applying the proposed method, i.e. reduce the consumption of pulse-forming gas several times. Cro ~ s ₀ IU addition, since this method requires less heating of the droplets, the less will be heated and the product to which is welded a drop that will improve product quality, because for them undesirable overheating, for example, fuses. The accuracy of metal dosing is also improved, and the compressed end of the electrode always has the correct geometric shape, which plays a role in the repeated excitation of the arc.

Claims

The invention relates to the field of electric arc welding and brazing in a protective environment. gas, and more specifically to methods of controlling the transfer of an electrode metal in the form of a single drop using a pulsed gas dynamic force, and can be used in the manufacture of products that require the application of small amounts of molten metal. There is a method according to which a control action of a gas is created by periodically moving a gas stream ril moving along an electrode axis. However, the application of this method in welding and brazing with a single drop leads to uneconomical gas consumption, since the focusing gas will expire with an increased flow rate during the entire welding cycle. In addition, with a large gas flow, a significant portion of the heat of the electric arc is carried away, which requires an increase in the arc current. The closest to the technical essence and the achieved effect to the proposed method is a welding process consisting in supplying gas flow pulses to the melting end of the electrode with a certain frequency from the pulsator. This method can be used in controlling the small-drop transfer during welding and brazing with a single drop of G21. However, the use of this method in electric arc welding and soldering with a single drop also leads to an increased consumption of a pulse-forming gas and an increased arc current. This is due to the fact that in this method the arc shutdown and opening of the pulsator are not synchronized so that the arc is turned off at the moment when the gas velocity around the opening drop reaches the maximum value. As a result, the gas velocity around the drop at the end of the electrode may reach a maximum, either when a drop has not yet formed, or some time after the electric arc is turned off. As a result, a drop of insufficient mass is released (besides, it is sprayed, as the arc is still burning), or a drop of molten metal at the end of the electrode has time to cool down and, therefore, a large initial temperature and high velocity of gas is required to detach the drop, i.e. it is necessary to increase the arc current and the gas flow rate. The purpose of the invention is to improve the quality and efficiency of the welding process by eliminating the drop drop and overheating the product, reducing the flow rate of the pulse-forming gas and electric power. The goal is achieved by the fact that in this method the pulse gas is turned on before the arc is turned off. which the gas-dynamic force, acting on the drop on the drop, reaches its maximum magnitude, the delay of the maximum of the gas-dynamic force relative to the open pulsator occurs, which occurs in the channel and nozzle The gas passes from the pulsator to the drop at the end of the electrode, there is a gas which is accelerated by the gas, the output is w; after a certain time, it leaves the pulsator. It is during this time that the velocity of the gas around the droplet and, therefore, the gas-dynamic force acting on the droplet reaches its maximum value. Such synchronization of opening the pulsator and switching off the arc ensures that the electric arc is switched off and that moment when the gas velocity around the drop at the end of the electrode reaches its maximum value. In this case, the gas-dynamic force acting on the drop will be maximum when the temperature of the drop is; maximum, i.e. when the surface tension force holding a drop on the electrode will be minimal. This will reduce the gas velocity in the pulse and heat the drop, i.e. reduce gas consumption and electric arc current. The drawing shows a diagram of the process parameters of electric welding with the proposed synchronization. The diagram indicates: b-time: T is the temperature of a drop of metal; J is the current of the electric arc; U) ic, is the voltage controlling the winding of the power contactor when the current is switched off dyj UZ K –voltage controlling the device that opens the pulsator, for example, the winding of an electropneumatic valve; P is equalizing pulsed gas power; - the delay time of the maximum gas-dynamic force per drop relative to the opening of the pulsator. In order for the gas-dynamic force acting on the drop to be maximum at the moment of its maximum temperature, it is necessary to open the pulsator earlier than to turn off the electric arc for the same time t, for which the gas-dynamic force will increase to the maximum value. The delay time f is determined experimentally and is determined by the control unit of the soldering or welding equipment. Example. Conducted surfacing drops of copper weighing 80 kg, electrode diameter 1 mm. The electric arc melts the electrode wire and forms a drop of molten metal. When the droplet acquires a certain size and weight, the electro-pneumatic valve is turned on, the pulsator opening. When the gas velocity near the drop at the end of the electrode approaches the maximum, the electric blow is turned off and the drop is pulled off by the gas-dynamic force of the gas flow, which is directed to the drop by a nozzle. The time lag in the application of the burner is O, 1 s. The process controls the arc current and the gas pressure in the pulsator, which are necessary to lift a drop of molten metal from the electrode. For comparison, the same parameters are determined during the deposition process without the proposed synchronization, when the electric arc is turned off simultaneously with the opening of the pulsator. The data are tabulated. If the difference in the times of the drawdown of the power contact, which disconnects the electric arc, and of the solenoid valve, which disconnects the pulsator, is significant, then it should also be taken into account when the process is synchronized. In this example, this difference is not significant and is not taken into account. The economic efficiency of the proposed method is determined as follows. The time at which the gas-dynamic force acting on the drop at the end of the electrode increases to a maximum is 0.1-0.2 s. As a result of the fact that, in the burners used for such methods, a massive current-carrying mouthpiece, heat sink from the electrode and drops into the mouthpiece are relatively large, and during the indicated time, the drops drop by several tens of degrees depending on the mass and heating value. Since the surface tension of metals depends on temperature; Then, when a drop of metal is cooled down, the force holding it at the end of the electrode will increase several times, i.e. it is necessary to increase several times the gas-dynamic force necessary to detach a drop from the electrode. The application of the proposed method will make it possible to tear off a drop that did not have time to cool down with a pulsed gas-dynamic force several times smaller than Before applying the proposed method, i.e. to reduce the consumption of pulse-forming gas several times. In addition, since this method requires less heating of the droplet, it will be less heated and the product on which a drop is deposited will improve the quality of the products because overheating is undesirable for them, for example, for fuses. The metering accuracy of the metal is also improved, and the drop end of the electrode always has a regular geometric shape, which plays a certain role when the arc is re-energized. The method of electric welding and soldering by single drops, in which, after forming a drop, the electric arc is turned off, and the drop is denoted by a pulsed gas-dynamic force, so that, in order to improve the quality and increasing the process economics by eliminating the drop cooling and overheating the product, reducing the flow of the pulse-forming gas and electricity, the gas pulse is turned on before the arc current is turned off, for which the gas-dynamic force acting on the drop has reached maximum value. Sources of information, taken into account in the examination 1. The author's certificate of the USSR Nb 335054, cl. B 23 K 9/16, 197О.

2.Patent UK. No. 1372518, class B 23 K 9 / OO, 1975 (prototype).