SU1053993A2 - Method of electric arc welding by consumable electrode with short-circuiting of the arc cap - Google Patents

Description

2. The method according to Claim 1, in which the displacement v of the end of the electrode wire in the direction from the bath of liquid metal is carried out by applying a force in the direction perpendicular to the axis of the wire.

The image relates to welding technology, in particular, to methods of electric arc welding with a melting electrode with short-circuits of an arc gap. -5

According to the main auth. No. 5b32.1, a method of arc welding with a short-circuit arc arc welding arc is known.

wherein the voltage drop 0 and the current on the jumper are measured continuously and a short-term current is reduced by the time the jumper is broken, at which the switching time is determined by the measured values 15 attaining a predetermined threshold value 1.

However, when using this method for electric arc welding with a melting electrode with short circuits of the arc gap in carbon dioxide, it is possible to reduce the metal sputtering to only 2-5% due to the fact that it is not possible to completely eliminate explosive processes when the jumpers of liquid are destroyed. 25 talla. The switching time of the welding current is determined by the achievement of the voltage drop across the jumper of a predetermined threshold voltage. At the same time, the voltage drop across the jumper, 30 on which the monitoring of its condition is performed, gives insufficient touch. information about the fprme and the size of the lintel before it is destroyed. The threshold voltage 4-6 V j is chosen experimentally from the condition of the minimal likelihood of late current switching (when the jumper is destroyed with an explosion at the front of the current deceleration, and not in the como-mutation interval) and early current switching (when the jumper does not have time or cannot be destroyed in the switching interval, but destroyed with an explosion after switching on the current. Moreover, an increase in 45 threshold voltage leads to an increase in the likelihood of late switching, and a decrease in the threshold

voltage - to increase the likelihood of early switching. Thus, the known welding method does not ensure minimal spatter of the electrode metal and, consequently, an increase in the quality of the welding process.

The aim of the invention is to improve the quality of welding by reducing the spatter of the electrode metal.

This goal is achieved by the fact that according to the method of arc welding with a melting electrode with short circuits of the arc gap, in the switching current of the welding current the end of the electrode wire is moved from the bath of liquid metal, increasing the length of the liquid jumper until it breaks and forming a drop of liquid metal, the end of the electrode wire returns to its original position ..

In addition, the end of the electrode wire is moved in the direction away from the liquid metal bath by applying a force in the direction perpendicular to the axis of the wire.

Moving the end of the electrode wire in the switching interval of the welding current in the direction from the bath of liquid metal leads to an increase in the length of the liquid bridge and a decrease in its diameter, i.e. enhances the effect of surface tension forces; in addition, an inertial force acts additionally on the mass of the liquid metal, which is possible when the electrode moves rapidly away from the liquid metal bath, which also contributes to the reliable destruction of the jumper, without an explosion, resulting in a reduction in metal splashing and increase quality of the welding process. Returning the end of the electrode wire to its original position after the end of the switching interval of the welded current contributes to the reliable formation of a jumper when the molten metal drop is touched to the liquid-metal bath, which reduces the splash resistance of the metal and improves its quality. welding process. In addition, the application of a force in a direction perpendicular to the axis of the wire allows one to obtain the maximum speed of movement of its end and to achieve the required amount of movement (approximately 0 mm of the wire’s end in the direction from the molten metal bath in the switching current of the welding current, resulting in a decrease in metal spraying and the quality of the welding process is improved. The drawing shows the current charts of welding current; iT is the voltage across the arc gap and and the phases of the process of dropping and breaking liquid metal .. Example. An electric arc welding with a fusible electrode with short circuits (MI arc) is sensitively conducted in a protective gas (carbon dioxide) medium using a CB-L872S wire with a diameter of 2 mm, in the mode: Svsr 180-200 A; Idsr 20-22 V. The proposed welding method is implemented using a thyristor current switch ff in combination with an electromagnetic device for moving the end of the wire. The switching time of the welding current is determined by means of a sensor monitoring the state of the jumper of the liquid metal. The process of arc welding with short-circuit electrode in a white electrode is accompanied by periodic closings of the arc gap of the first electrode metal melted during arc burning. At the moment of time the drop of metal touches the structure to be welded, thus forming a bridge of liquid metal (drawing). The voltage across an arc gap id drops sharply from 25–30 V to almost zero, and the welding current Jj.g begins to increase with a constant time determined by the electrical parameters of the welding circuit. As the short circuit current increases in the time interval tj, the liquid metal jumper is compressed under the action of electromagnetic forces, the jumper resistance increases and the voltage drop across the jumper increases, which is continuously measured and compared with the threshold voltage fpop. In this welding method, the Threshold value ( Uftop voltage is chosen as the minimum (3, to completely eliminate the late switching of the welding current (when the bridge of liquid metal with an explosion is destroyed at the front of the current decline. Momemt com The tj welding values are determined by the fall of the voltage across the jumper to a predetermined threshold voltage. At this time, the welding current is reduced 3j. from the maximum value 300-500A to the minimum WOGTi1ll l lg .cgrTiin 10- 20A. The switching period of the welding current -G "0.7- - - -ki 1 from the time the switching current of the welding current moves the end of the electrode wire in the direction from the bath of liquid metal to a distance of mm by applying a force in the direction perpendicular to the wire axis. The amount of movement of the wire end. K was chosen experimentally approximately equal to half the diameter of the wire (i.e. 1 mm with a wire diameter of 2 mm), the outcome and the conditions for ensuring minimum metal spraying of 1.5-3.5%. As a result of moving the end of the wire, the jumper is stretched by 1 mm. Under the action of the surface tension force and the inertial force, the jumper is disassembled without an explosion at time 14 within the switching interval. At the same time, an auxiliary arc is excited. At the time tg of the end of the switching interval of the welding current, the main arc is ignited, the electrode wire begins to melt, and a drop of liquid metal is formed. At the same time, I return the end of the electrode wire to its original position in the time interval tg-t (5-10 s). At time t, a drop of metal touches the structure to be welded.

S1053993ft

about 10% of the liquid metal sintering with the base object (prototype, and the welding cycle is repeated. type J. Experimentally found that the proposed metal leads to an increase in the quality of the welding process according to the offer, (melting with a short electrode comparing with the basic niche of the evmykiya of the arc gap by the object, as well as to the economy, the electrode allows to achieve the minimum different wires, electric power and mvialla laboring (about 1.5 costs for cleaning the welded end L, i.e., 0 1 - l, “times according to the struc tures of metal spatter.

Electrode spatter reduction

Claims (2)

| 1. METHOD OF ELECTRIC ARC '(WELDING BY FLOATING ELECTRODE WITH SHORT CIRCUITS OF THE ARC INTERMEDIATE according to autoswitch No. 563241, distinguishing with' in order to improve the quality of welding due to the reduction of metal spatter in the inter- the welding current, the end of the electrode wire is moved away from the molten metal bath, increasing the length of the liquid wire before it ruptures, and after the end of the switching interval of the welding current and the formation of a drop of liquid metal, the end of the electrode wire is returned to its original position nie. 2. The method according to claim 1, about t and h and y'shch and th with the fact that moving ·. the end of the electrode wire in the direction from the molten metal bath is carried out by applying a force in the direction perpendicular to the axis of the wire.