DD215029A1 - METHOD AND CIRCUIT ARRANGEMENT FOR TURNING THE ARC TOOL AND FILLING THE END CIRCULAR IN UPWITCH WELDING, IN PARTICULAR INTERRUPTED MEASURES - Google Patents

Abstract

The object of the invention is to allow a semi-automatic and automatic UP welding of particular interrupted Kehlnaehten, which ensures a repeated trouble-free Zuenden the arc and a flawless Endkraterausbildung. This object is achieved by a method and a special circuit arrangement, such that the operating point of the arc is displaced at the time of Zuendens interrupted at the weld end with interruption of the movement simultaneously or after a time interval, the wire feed and the increased arc voltage is reduced and after an interval is switched off with resumption of the wire feed, briefly thereafter, the arc voltage is applied again and the arc and wire feed characteristic is changed, with lifting the interruption of the drive increases the driving speed in the non-welding section and is reduced at the time of Zuendens to the welding speed.

Description

Method and circuit arrangement for igniting the arc and pulling the Sndkrater in UP Keblnahtschweißen, in particular interrupted fillet welds

Field of application of the invention

The invention relates to a method and a circuit arrangement for igniting the arc at the beginning of a weld and pulling the Schweißnahtendkrater in semi-automatic and automatic submerged (UP) fillet weld, in particular interrupted fillet welds.

Characteristic of the known technical solutions

In order to ensure a quality-compliant weld, the flawless ignition of the arc and the pulling of the end craters must be realized. For the ignition of the arc found in the prior art ignition aids, such as squib and HP ignition devices application. An automatic repeated trouble-free ignition, as it requires the interrupted UP fillet weld, could so far

not be solved satisfactorily.

A common starting point for further welding defects is the improperly formed end crater at the seam end.

To avoid these errors, the end crater must be filled in without penetration marks.

In known devices for semi-automatic and automatic welding of fillet welds, the end crater filling is achieved by reducing the arc power and reducing the wire feed. The reduction of the arc power is realized either by a resistor arranged in the welding circuit or by the arrangement of an additional resistor in the exciter circuit of the welding transformer.

Also known is a solution according to DD WP 84309, which ensures the filling of the end crater in semi-automatic inert gas welding, in particular interrupted fillet welds.

An application of this known method is not possible for interrupted UP fillet weld, as in the UP welding

- The reduced arc performance and the throttling of the wire feed during the Endkraterfüllung does not eliminate the lack of the formation of Einbrandkerben.

- The throttling of the wire feed is insufficient and also the reduction of the arc voltage described in DD WP 84309 leads to Einbrandkerben in the entire process of Endkraterfüllung.

- maintaining a continuous welding speed during end crater filling is not applicable.

Object of the invention

The aim of the invention is to enable a quality weld in the interrupted UP fillet weld.

Explanation of the essence of the invention

The invention has for its object to develop a method and a circuit arrangement, which makes it possible to weld the semi-automatic and automatic UP-fillet weld trouble-free arc at the beginning of the seam and form the end crater error-free.

According to the invention, the object is achieved in that by using thin wires in conjunction with a special circuit, the operating point of the arc is temporarily shifted at the time of ignition in a range in which a trouble-free ignition is guaranteed without Hilfst niittel, after a time interval, the parameters abut again for the normal welding process, interrupted after completion of the weld and interrupting the movement in the welding direction after a certain time interval for Endkraterfüllung the wire feed and simultaneously resulting from the interruption of the wire feed increase the arc voltage is reduced and after another interval, the welding voltage is switched off with simultaneous connection of the wire feed and briefly thereafter, the arc voltage is applied again.

The welding parameters, welding voltage and wire feed are changed in all phases of the end crater filling so that an error-free end crater formation is guaranteed.

The Sndkraterfüllprozeß is finished with resumption of movement in the welding direction. With the resumption of the sequence of movements in the welding direction, the driving speed is increased until the beginning of the re-ignition of the electric arc. At the time of ignition, the vehicle speed is reduced so that it corresponds to the welding speed.

To carry out the method, resistors and switching elements have been arranged to the existing resistance of the welding power source, to the actuators of the drive and the DrahtvorSchubes, to control elements of welding equipment, which are switched by means of time-dependent, and -independent switching elements according to a time program, so that set the parameters of the method according to the process-typical conditions according to the illustrated circuit arrangement.

Ausfübrungsbeispiel

The invention will be explained by means of circuit diagrams on the accompanying drawings of an embodiment.

The circuit consists of 2 control circuits, wherein

Pig.l the circuit for igniting the arc and

Pig.2 and 3 the circuit arrangement for filling the S'ndkraters (Figure 3 as a continuation of Pig.2)

represents.

With the beginning of the welding process to improve the ignition characteristics after closing the contact dx / 1 by a current path 1 arranged in the relay d .. the variable resistor 3 in the welding power source 1 through the contacts d-, /, - and d- , r disconnected and by means of the contacts dw. and d ^. replaced by the resistor 2. As a result, the operating point of the arc is shifted into a region which is more favorable for the ignition of the arc.

In the event of a time interval, the relay cL drops out by the time-dependent relay d "by means of the contact dp / ^, the parameters of the method which were set before closing the contact dx / 1 again being present.

Before completion of the welding process, the final crater filling process is initiated by the relay d ~ with the closing of the contact dy / 1, in which the contact d-3 / k interrupts the traction drive 4 on the actuator 5 of the motor and with the contact d ^ / p at the same time Relay Ä. Switches on after a period of time with the contact dy ₈ the wire feed 6 on the actuator 5 of the motor interrupts and with the contact ^ä 4/10 ^{di> e Kennl} i ^{nie aer} welding ^power source 1 by connecting the resistor 7 in series with the changed in the welding power source 1 variable resistor 3 changed. The relay d. switches with the contact d./o at the same time the relay d, -, which shuts off after expiry of a further time interval by means of the contact ^ä 5/14 ^ ^{e Sc} ^ a ^{; s} P ^ss S, the characteristic change by means of the contact d ^ / io ^un u ^ ^{e s} wire feed interruption by the contact d ^ / g repeals.

Simultaneously with the resumption of Drahtvorschu bes and the cancellation of the change in the characteristic is determined by the contact dr /. the time-dependent relay dg switched on, which after expiration of another

Time interval, which ends at the latest at the time of the impact of the wire on the surface of the workpiece after it has stopped on the wire before thrust 6, the welding voltage is switched on again by the contact ^ c / jc , whereby at the same time dr / tc »^ 6 / 17 ' ^ä 6/18' ^ f / 19 ^ ^he variable resistor 3 of the welding power source 1 by the variable resistor 10 and by d ^ / » ₀ » ^ä 6/21 '^ 6/22 * ^ä 6/23 of ^the S ¹¹ e ^ ⁰⁶¹ " ⁸ ^ ⁸¹¹ " ³ 12 of the wire feed 6 in the actuator 5 is replaced by the resistor 11. Thus, the actual end crater filling begins with special welding parameters The contact dß / cr switches the time-dependent relay d ~, which after a time interval, the the time for filling the Endkraters corresponds to the wire feed and the welding voltage through the contact dy / -, - by means of the relay 9 in the control unit for the welding 8 switches off and the interruption of the travel drive 4 through the contact ay / j cancels.

Simultaneously with the cancellation of the interruption of the traction drive 4, the variable resistor 13 of the actuator 5 of the traction drive 4 by means of the contacts ^d 7 / '> 4 ^and ^ 7 / P ¹ I ^{and <3 of} Wi l ^first l ^{it changed} 14 so that the time of relative movement in the welding direction in the non-welding section of the welded joint is reduced.

At the time of the re-ignition of the arc at the start of the seam, opening the contact d / switches off the control until the end crater filling is started.

Claims (3)

invention claim 1. A method and circuitry for igniting öea arc and Pullen the end crater in the 'automatic and automatic automatic up-Keblnahtschweißung, in particular interrupted fillet welds, using a shutdown of the arc voltage, characterized in that at the time of ZUndens the operating point of the arc temporarily is shifted to the area in which a trouble-free ignition is guaranteed without aids and that interrupted at the weld end with interruption of movement in the welding direction simultaneously or after a certain interval, the wire feed and simultaneously resulting from the interruption increase in the arc voltage is reduced and after expiration a further interval, the arc voltage is switched off while resuming the wire feed and briefly thereafter, the arc voltage is applied again, the arc and wire feed characteristic so ve is changed, that a filling of the Endkraters is ensured and that after completion of Endkraterfüllens with resumption of the movement in the welding direction, the driving speed in the non-welded portion of the welded joint increases until the beginning of the re-ignition of the arc and at the time of ignition is reduced to the welding speed. 2. Circuit arrangement for carrying out the method according to item 1, consisting of resistors, time-dependent switching elements, characterized by additional resistors (2; 7; 10; 11; 14) and switching elements (d ^ - dy), the welding power source (1) and the welding device be assigned so that during the time of circling and the final crater filling in the interrupted welding set the parameters of the process, such as wire feed speed, welding voltage, welding (Pahr) speed accordingly. - For this 3 pages drawings -