DD222811A1 - CONTACT DUESE FOR WELDING BURNERS - Google Patents

Abstract

The invention relates to a Kontaktduese for welding torch for inert gas welding with consumable electrode and for welding with Fuelldrahtelektrode. The Kontaktduese consists of two Kontaktduesenhaelften, which are used in a conical receptacle in the intermediate piece of the welding torch and are constantly pressed by the feed of the wire electrode in this conical receptacle. As a result, the Kontaktduesenhaelften always be in their front region on the wire electrode, so that good current transition is guaranteed. In addition, the mechanical wear is compensated within limits selbstlichet. After a correspondingly large wear of the front piece of Drahtelektrodenfuehrungsnut the Kontaktduese can be turned by 180.

Description

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According to the invention the object is achieved in that the contact nozzle consists of two contact nozzle halves with approximately semicircular cross-section whose height is less than half the width, wherein on the flat surfaces of the contact nozzle halves in the longitudinal direction per a Drahtelektrodenführungsnut is incorporated so that after inserting the wire electrode in this Drahtelektrodenführungsnut and the merging of the contact nozzle halves between the flat surfaces of the contact nozzle halves there is a gap and that the contact nozzle halves are provided at both ends at the periphery with a partial cone of preferably 8 ... 10 °, for inserting the contact of the nozzle halves contact nozzle in the correspondingly shaped intermediate piece of the welding torch is required.

embodiment

The invention will be explained in more detail below using an exemplary embodiment.

In the drawing show:

Fig. 1; the top view of the welding torch tip '

2 shows a side view in section acc. Fig. 1

The contact nozzle halves 2 and 2 'are combined to form the contact nozzle and inserted with the lower part cones 3 in the intermediate piece 1. The wire electrode 4 is inserted through the wire electrode guide groove. Between the contact nozzle halves 2 and 2 'the gap 7 is, the contact nozzle halves 2 and 2' are under tension on the wire electrode 4 at. The protective gas

flows out of the protective gas chamber 5, which is formed by the intermediate piece 1 and the cap 6.

The mode of operation of the contact nozzle according to the invention is the following:

The contact nozzle halves 2 and 2 'are combined to form the contact nozzle and inserted with the cone formed from the cone part 3 in the cone seat of the intermediate piece 1. The wire electrode 4 is inserted into the wire electrode guide groove, which is half incorporated in the contact nozzle halves 2 and 2 '. The fact that the height of the approximately semi-shaped profile of the contact nozzle halves 2 and 2 'is less than half the width of the profile, the gap results in 7. The feed of the wire electrode 4 now causes the contact nozzle halves 2 and 2' with their partial cones third firmly pull into the cone seat of the intermediate piece 1. As a result, the wire electrode 4 is in voltage in the wire electrode guide groove and a good current transition is ensured. Also caused by the feed motion mechanical wear of Drahtelektrodenführungsnut is thus constantly compensated within limits automatically, as the feed movement causes a constant pushing the contact nozzle halves 2 and 2 'in the spacer 1 and so the contact nozzle halves 2 and 2'stets under tension on the wire electrode 4th issue.

The Drahtelektrodenführungsnut may have different cross-sections, z. B. somewhat circular as in the embodiment, square, prismatic and the like. During operation, the Drahtelektrodenführungsnut now works in the contact nozzle on the side facing the welding torch by the constant friction during advancement of the wire electrode 4 connected to heat action by arc proximity of conical, so that the contact point for the current transition in the direction of contact nozzle end wanders. The actual free end of the electrode is thus longer and there are disturbances in the welding, which can be partially compensated by adjusting the welding voltage. If the contact nozzle is worn too much, there are interruptions to the arc or the arc breaks completely. The contact nozzle must then be replaced. According to Munske "Handbuch der Schutzgasschweißens", page 160, the free end of the electrode must be relatively short, so that the resistance heating of the end of the wire electrode 4 remains within the permissible limits despite high current densities, that is to say that at least in the region of the contact nozzle which is the workpiece In the case of the contact nozzle according to the invention, this region is located approximately in the area of action of the partial cones 3. The ends of the contact nozzle halves 2 and 2 'provided with the partial cones 3 thus become secure pressed against the wire electrode 4. The pressing force then decreases in the direction of the partial cone 3 'and the ends with the partial cone 3' are only slightly or not at the wire electrode 4. Is the Drahtelektrodenführungsnut at its front end now so worn that the contact nozzle must be replaced, it is in the embodiment of the invention possible to turn the contact nozzle halves 2 and 2 'and insert with the sub-cones 3' in the intermediate piece T.

As a suitable material for the contact nozzles, a tungsten-copper impregnated alloy has a ratio of 70:30

proven. ι

The erfindungsgernäße two-piece contact nozzle is simple and thus functionally reliable. It is ensured that the contact nozzle halves rest securely against the wire electrode, at least in the lower region facing the workpiece, thus allowing unimpeded passage of current. The mechanical wear of the wire electrode guide groove is in

Borders automatically compensated. ;

In case of excessive wear of the workpiece side Drahtelektrodenführungsnutendes the contact nozzle can be turned by 180 ° and used again.

Claims (1)

-1- 261588 3 invention claim Contact nozzle for welding torch for inert gas welding with melting electrode or for welding with Fülldrahtelektrode, wherein the contact nozzle is made of several parts and preferably a hard, conductive material, characterized in that the contact nozzle of two contact halves (2, 2 ') with approximately semicircular Ouerschnitt whose height is less than half the width, wherein on the flat surfaces of the contact nozzle halves (2, 2 ') in the longitudinal direction per a Drahtelektrodenführungsnut ^ o is incorporated, that after inserting the wire electrode (4) in this Drahtelektrodenführungsnut and folding the Contact nozzle halves (2, 2 ') between the plane surfaces of the contact nozzle halves (2, 2') a gap (7) and that the contact nozzle halves (2, 2 ') in its two ends at the periphery with a partial cone (3, 3') of preferably 8 ... 10 ° provided for inserting the from the contact nozzle halves (2, 2 *) existing n Contact nozzle is required in the corresponding shaped intermediate piece {1) of the welding torch. For this 1 page drawings Field of application of the invention The invention relates to a contact nozzle for welding torch for inert gas welding with consumable electrode and for welding with Fülldrahtelektrode. Characteristic of the known technical solutions It is common practice to transfer the necessary welding current to the wire-shaped electrode via a contact nozzle, which is usually made of copper or copper alloys, which is part of the welding torch, so that the wire-shaped electrode is guided through the center bore of the contact nozzle and the current is thereby transferred , The wire-shaped electrode is only in places on the inner wall of the central bore, so that an indefinite contact surface is present, which is constantly smaller due to the mechanical wear caused by the wire feed. Thus, the formation of small arc within the central bore of the contact nozzle and the formation of copper oxide on the current-transmitting surface is favored and it thus occurs an increase in the contact resistance and thus inferior passage of current. As a result, the welding parameters are adversely affected and there is a deterioration in the quality of the weld. Even if the contact nozzles are cleaned regularly, the service life is very low due to the mechanical wear and the incoming electrical erosion associated with intense heat. Munske notes in the 1975 published second revised edition of the textbook "Handbook of inert gas welding" p 161 that the current is still slipping on structurally poorly trained contact nozzles with high current density in the splash and high temperature range of the arc is transmitted By appropriate design of the contact nozzles, it is attempted to achieve both a constant good passage of current and a longer service life of the contact nozzles, but the solutions which have become known have not become established in practice for various reasons. So z. As known from DD-PS 146016, the wire-shaped electrode to form weakly wave and only then to pass through the central bore of the contact nozzle. The waveform gives a spring effect, which should increase the contact pressure within certain limits and compensate for mechanical wear. The possible success, however, is not acceptable to the increased cost of forming the wire electrode. It is also known to make the contact nozzles of several parts. So z. As resilient contact strips or resilient supports (DD-PS 66236 and 124900) used, which form the contact nozzles together with solid stops or pads. As a result, a constantly consistent good passage of current is achieved and the wear can be reduced. The chosen design principle requires but due to the springs large geometric dimensions of the contact nozzles, which are also complicated in construction and thus prone to failure especially by the heat load of the springs and the influence of the spatter on the moving components. The same applies to such contact nozzles, which consist of a solid, poorly conductive and a movable, highly conductive jaw, such. shown in DE-AS 2331415. It has also been attempted to guide the wire electrode in a well-conducting guide piece and to press on a low-wear Anpreßstück whose contact pressure is generated via a bimetallic spring, the contact pressure with increasing temperature increase of the contact nozzle parts also increases. (DD-PS 150707) This design also requires high production costs. , There are also contact nozzles, in which the wire electrode is surrounded by highly conductive fillers in order to achieve a good electrical contact. These fillers are located in a tubular part that is closed at the bottom and top with a pierced lid. Through the cover holes, the wire electrode is guided (DD-PS 96875). A particular disadvantage here, however, that the threading of the wire electrode is difficult. Object of the invention The aim of the invention is to eliminate the disadvantages and to provide a contact nozzle for welding torch, which is simple and thus a little effort to produce, has small dimensions and as well as thin wire electrodes used and low maintenance and prone to failure. In addition, a material saving by extended usability should be possible. Explanation of the essence of the invention The object of the invention is to provide a contact nozzle for welding torch for inert gas welding with abschmelzender electrode and for welding with Fülldrahtelektrode, which makes it possible to automatically compensate for the resulting by the advance of the wire-shaped electrode mechanical wear on the central bore of the contact nozzle, thereby simultaneously a consistently good Power transition between the wire electrode and contact nozzle is ensured and thus significantly increases the life of the contact nozzles. Furthermore, the contact nozzle should be designed so that it is applicable by 180 ° and thus a further increase in the life occurs. '