SU1278151A2 - Method of electric arc welding with consumable electrode with arc gap shorting - Google Patents

Abstract

The invention relates to arc welding with a short-circuit arc electrode. The aim of the invention is to increase the sustainability of the process. The method is characterized by the fact that in the period from the beginning of the short circuit t, until the end of the switching of the current, the arc t slows down or stops the supply of the electrode. At time tg, the bridge is destroyed without an explosion by the action of surface tension and inertial forces. The control of electrode metal transfer allows one to expand the range of stable welding modes with minimal spatter. 1 il.

Description

Yu

h |

00

The invention relates to welding technology, in particular to methods of electric arc welding with a melted electrode with a short blink of a coal gap, and is an improvement of the method according to the author. 747642.

The aim of the invention is to increase the stability of the welding process.

With the pre-full-arc method of arc welding, an electrode with a short arc arc delay slows down or stops supplying the electrode to the welding zone at the beginning of a short lock; arc arc ducting for a short sai aikani period and current period and again turning on the electrode feed when excitation occurs main arc.

Slowing or stopping the supply of the electrode to the zone of the weld in the beginning, ale: xo of a short-circuit closure at an indication of a time period. It reduces the diameter of the jumper. As a result of slowing down the electrode supply, the length increases and the diameter of the jumpers decreases and the stub (the process of their destruction shortens. The short circuit time is shortened and the maximum short-circuit current decreases. closure an, in which the beginning. aegs) 1ntence is destroyed by the jumper and an avalanche-like increase in the fall of tension on it.

By reducing the short circuit time and stabilizing the destruction of the jumpers, the stability of the Stage 1n-1 short grid drive and the process as a whole is increased, which makes it possible to increase the probability of reducing the threshold voltage of the jumper state sensor and increasing the current switching interval. the occurrence of normal (without current) destruction of jumpers. A decrease in (the axial magnitude of the short circuit current, the increasing stability of the process, an increase in the likelihood of normal current commutation, expands the region of resistant welding with minimal metal sputtering.

Determination of the onset of slowing down or stopping the electrode feed by my

A short-circuit current threshold is achieved by ensuring that the melted metal drop is fused from the weld pool during the short-term initial stage; kak :: and allows stabilizing the arc gap and the main arc burning after the breakdown of the arc, to prevent the occurrence

short-circuiting when the electrode is accelerated when the wire is broken, which helps stabilize the transfer process of the electrode metal and reduce its splashing.

In addition, slowing down or stopping the supply of the electrode and turning it on Hi .te again, respectively, by braking and disrupting the electrode directly at the entrance, to its current-conducting tip with a braking gain 1 and. , depending on the current of a short 3 .1 scan, and will forcefully release 1va .-- w, depending on it, on the current of the main ARC1- :, allows you to achieve the maximum speed of changing the electrode feed rate at the output of the current-carrying tip and, then. m, maximum effect reduction spray me; tg: lla and improve the quality; 1process; sa welding.

In the drawing, the time diagrams of the welding current I. are presented. The voltage across the arc line; Un. -and

speed, feed end1 of the electrode into

the Vfioi welding zone and the phases of the drop-forming process and the electrode transfer-. metal, in a barbed bath.

EXAMPLE. An electric arc about welding a plug-in electrode with a short wavelength: arc arc of the proposed method is carried out in a protective (gas: gas) gas with a fiber SB-08G2S with a diameter of 1, 62 mm on re; kimah: 1 ,,, 180-230 A, etc. - 22-25 V. The method of welding is reactivated with the help of a thyristor current switch in combination with an electromagnetic brake, which is mounted in the handle of the torch of the semi-automatic device. The switching times of the welding current are determined by the respective sensors.

55 The process of electric arc welding using a short arc arc-1ms electrode is accompanied by periodic closures of an arcuate curvature of an electrode metal molten during the main arc burning, At the time t when the voltage on the arc gap reaches and the threshold value U (, cp.T This is limited to a value of 2-30 A for a period of time C, 0.1-1 ms. The threshold voltage UPP is set in the range of 5-15V due to the reliable detection of the beginning of a short circuit. The lower limit of the range is limited by the pad the voltage at the departure, the upper - the lower limit of the voltage Ug. during the period of changing the arc. The lower limit of the current 2A is taken from the condition of reliable arc burning in the switching interval G, in the event that as a result of the current limitation it was not possible to translate the short-term short circuit is long. At a current of more than ZOL, the effectiveness of current limiting decreases, i.e. the number of short-term short circuits significantly increases. The duration of the current switching interval, 0.1-1 ms, is determined from the condition of the time required to form the jumper, while its upper limit is determined by the stability conditions of the welding process. From the time t, the short circuit current does not increase with a constant time determined by the electrical parameters of the welding circuit. When the short circuit current reaches the threshold value. Neither I Pori (moment tj) begin to slow down the electrode supply by braking the electrode near its entrance to the current-carrying tip with a braking force depending on the short-circuit current. The threshold value If, (, p is set greater than the current limit in the switching interval, under the condition that a drop of molten metal is fused from the weld pool due to electrode feed, surface tension forces and electromagnetic forces. At time t, the electrode feed at the output from the current-carrying tip is stopped, while the distance from the end surface of the electrode to the surface is welded; my design and the length of the jumper remain almost unchanged, 1m before the main arc is excited During the period of braking of the electrode near its entrance into the current-carrying tip without stopping the feeding mechanism, the electrode is fed into the space determined by the difference in diameter of the electrode wire and the internal diameter of the feeding hose. this reduces the diameter of the jumper, increases its resistance, and accordingly increases the voltage drop across the jumper, which is continuously measured and vnivayut a threshold voltage Unop. The value of the threshold voltage II is chosen the lowest (3-4V) in order to completely eliminate the late switching of the welding current (when the bridge of the liquid metal is destroyed with an explosion at the front of the current reduction). The moment of limitation, the current t is determined by the achievement of the voltage drop on the jumper of a given threshold voltage U "(,". At the same time, the current I ... is reduced from the maximum short circuit current to 10-ZOL. Switching period toka G2, 0.71 , 5 ms. At the moment tg under the action of surface tension forces and inertial forces, the jumper is destroyed without an explosion, an auxiliary arc is excited, during which time the current in the circuit is restored to almost the maximum value of the short-circuit current, the main arc The portage begins to melt, droplets of H1-1DI metal are formed.The moment tg of switching on the supply of the electrode is again determined by the eye of the main arc of a predetermined porous value. the entrance to the ambient tip with effort

51

disinhibition depending on the current of the main arc.

Threshold value

install less mini (top. g

minimum possible current of the main arc from the condition of stabilization of the arc discharge of the main arc after its excitation. In the time interval tg-tg, the electrode feed rate at the output of the current-carrying tip V "of increases to a value that is higher than its value until time t. The growth of the electrode feed rate is determined by the time it decelerates during the short circuit and the pruling properties of the electrode wire. At time tg, the speed is restored and becomes equal to the electrode feed rate until time t. At time t, a drop of liquid metal touches the structure being welded and the cycle repeats.

278151ft

Claims (1)

Controlling the transfer of an electrode metal by the pre-paged method of arc welding with a melting electrode with short-circuits 5 of the arc gap allows for expansion; a region of stable weld modes with minimal 1n (2%) spraying: metal consumption. The invention of the method of arc welding with a fusible electrode with short circuits of the arc gap according to the author. No. 747642, that is, in order to increase the stability of the process, in the period from the beginning of the short circuit, when the short circuit current reaches the threshold value and until the end of the arc current switching, when the threshold value is reached, it slows down or stop the flow of the electrode.