УЛУЧШЕНИЕ ПРОЦЕССА СВАРКИ В УГЛЕКИСЛОМ ГАЗЕ ПРИ МОДЕРНИЗАЦИИ ОБОРУДОВАНИЯ

Крампит А.Г.¹, Крампит Н.Ю.², Крампит М.А.³, Дмитриева А.В.⁴

^1,2Кандидат технических наук, доцент; ^3,4студент, Томский политихнический университет

УЛУЧШЕНИЕ ПРОЦЕССА СВАРКИ В УГЛЕКИСЛОМ ГАЗЕ ПРИ МОДЕРНИЗАЦИИ ОБОРУДОВАНИЯ

Аннотация

В данной работе авторы предлагают модернизацию имеющегося сварочного промышленного оборудования для выполнения сварки под импульсным источником питания сварочной дуги.

Ключевые слова: сварка при СО2, импульсно-дуговая сварка, влияние на сварочные процессы.

Krampit AG¹, Krampit NY², Krampit MA³, Dmitrieva AV⁴

^1,2 CS, associate professor;^3,4Student, Yurga Institute of Technologies (branch) of Tomsk Polytechnic University

THE IMPROVEMENTS OF THE WELDING PROCESS IN CARBON DIOXIDE AMBIENCE AT MODERNIZATIONS OF THE EQUIPMENT

Abstract

In given work authors offer modernization of available welding industrial equipment for performing of the welding under pulsed power source of the welding arc.

Keywords: welding in СO2, pulsed arc welding, actively influence welding processes.

Ключевые слова: сварка в CO₂, импульсно дуговая сварка, активное влияние на сварочные процессы.

Since 1949-1951г.г., welding in СO₂ ambience, due to cheapness of protective gas, has become to be used wider in machine building, first coal electrode [1] then  melting electrode [2] were used. The problems caused by negative influence oxidizing characteristic of protective gas, were overcame by introduction to welding wire manganese and silicon. At present, welding in СO₂ is used widely in industry. However, welding in carbon dioxide ambience is still used in its primordial type with all disadvantages inherent.

There are two directions for elimination of these disadvantages: the first one implies technologies reducing of drop splashing. For instance, choice optimum welding parameters providing stability of the process; using protective  screens and covering, providing reduction of drop-splashing..

The second direction allows actively influence upon processes, occurring in the arc itself. Given direction can be divided into parts after the way of introduction controlling influences:

- through wire i.e. by introduction alkaline earth element in welding wire components , as well as fixing activator on surface of the welding wire directly before welding [3];

- through gas protection i.e. pulsed protective gas stream [4], pulsed alternating of different protective gases (СO₂, Ar, He) [5], using  gas mixtures [6];

- through mechanisms of the welding wire feeding, i.e. pulsed and interrupted feeding mechanisms (mechanisms feeding welding wire) [7];

- through power supply of the welding arc i.e. using modulator, pulsed power source, different attachments, stabilizer, systems to switching welding source [8].

Recently equipment, applicable on Russia enterprises has worked out its resource physically and morally. At many enterprises, applicable equipment is found in usages more than 30 years. However, given equipment if being modernized and improved can further execute its functions. One of such improvements is the method of the arc welding current and voltages alteration [9]. Since for introducing of the welding into production, only small revision of power source is needed and accompaniment of the attachment.

In given work authors offer modernization of available welding industrial equipment for performing of the welding under pulsed power source of the welding arc. When use this method of welding, stability of the arc combustions increases. Therefore, directed operated transfer of electrode metal in welding arc in all spatial positions is provided, in consequence of which splash of electrode metal declines, electrode metal drop forming improves, a possibility of active influence upon geometric sizes of the welded seam and welded joint structure evolves.

At participation of the authors, a method of welding with pulsed feeding by long arc has been designed and marketed successfully [10]. The particularity of the given welding method is that an electrode metal drop melts and partly forms on interval of one welding current impulse, but final shaping and transfer of the drop occurs at the following interval of applying of welding current impulse. After transfer of the electrode metal drop, pulse-welding current does not stop, that causes the further active melting of the electrode and formation of following electrode metal drop, as well as energy dosage occurs, going on melting drop of the electrode metal. On interval of the pause, a drop under the surface tension power is evened on the butt end of the electrode.

The investigations were conducted on laboratory installation consisting of welding head GSP-2 with controller BARS-2V, modernized power source VDU-504 with modulator IRS-1200ADM [11]. Given installation can be used for automatic welding of various constructions in carbon dioxide ambience under pulsed power supply of the welding arc.

Modulator (pulsed controlled resistance) is executed as a nozzle to the welding direct current source, for instance, VDM-1001, VDM-1601, VDU-504(506) and others. The modulator source is intended for mechanized and automatic welding with consumable electrode by long arc in active and inert gas ambience and their mixture by open arc with utter section wire, as well as powdered wire in all spatial positions with operated electrode metal transfer.

The modernization of the welding rectifier VDU-504U3 is confined in following. From power part of rectifier, expelled choke and equalizing reactor were excluded that provides the greater velocity of welding current growth at imposition of the pulse. It is executed by simple closing the circuit of equalizing reactor input and wiring to point of the power cable joining.

For eliminating collapse when rectifying, regulator on faceplate is removed on maximum (also possible change power triple diodes for diodes, in this case the controller can be dismantled). The regulation of welding parameters is realized through parameters of the modulator.

The system (the modulator + power source) of the pulsed power supply has a following technical data:

Amplitude pulse welding current, Amp 300 – 1200;

Currents of the pause, amp 40;

Average currents, amp 100 – 300;

Frequencies pulse, Hz 25 – 150;

pulse duration, with 10-3 1 - 8

Using the pulsed power supply allows to vary the parameter of the welding in more broad limit (average value of the welding current and voltages) [13]. The welding under pulsed power supply is executed without short circuits (the long arc). The given process is characterized by big power influence of the welding arc during imposition of the welding current pulse. The periodic influence of the welding arc at change of impulse parameters allows influencing upon geometry of the welded seam, as well as on the structure of welded joint. Due to the power of the arc, process with pulsed power supply is expedient to use for welding of plate products in gap cutting. The laboratory tests of the modernized equipment have shown that the stability of the process of the welding in ambience of the carbon dioxide increases, the structure of weld metal improves, extent of the heat affected zone decreases, as well as the mechanical characteristics of the welded joint improve.

Deductions:

1. Given direction of the welding parameter pulsed change does not require the significant costs and allows to stabilize the welding process at improvement of technological characteristics of welded joints, therefore, the construction as a whole.

2. In process of the modernization, welding equipment allows to perform the welding on new qualitative level (at improvement of technological characteristics and receiving of the operated electrode metal transfer in all spatial positions).

Literature

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