SU933327A1 - Burner for gas-shield arc welding by consumable electrode - Google Patents

Description

The invention relates to ⁴ arc welding with a consumable electrode in carbon dioxide and can be used in large-scale branches of mechanical engineering · (carriage building, shipbuilding, chemical engineering and other fields) for welding alloys based on iron and carbon.

A device for shielded gas arc welding is known, comprising a cone-shaped protective shield made of a heat-resistant dielectric, mounted on the end of the current supply tube, protruding from the nozzle by about 13 mm, protecting the current supply tube and nozzle from splashing with metal drops and from overheating by arc radiation. [1] .

The disadvantage of this device is the rapid mixing of air into the annular stream of protective gas, · having a small thickness (1.6 mm) and a high flow rate, poor cooling of the protective screen, which leads to sticking, splashing on its surface, getting them into the welding zone and deterioration quality weld metal.

A known burner for arc welding in carbon dioxide, comprising a housing with a collector for supplying liquid carbon dioxide to the burner, a reducing device with calibrated holes located at the outlet of the burner, a contact tip rigidly connected to the current-carrying mouthpiece and made with a conical protrusion at its end [2]

The disadvantages of the burner are the poor protection of the welding zone from air due to the outflow of C0 <^ from the burner by separate thin streams and mixing of the gas stream with air during the sublimation of dry ice in the arc burning zone, since liquid C0 (^ is reduced at the outlet of the burner and gasified around or near z '933327 of the arc, and the inefficient use of liquid COq to cool the heated parts of the burner, since after reduction, supercooled to -78 ° C liquid COq is fed into the arc burning zone.

The closest in technical essence and the achieved effect to the invention is a torch for arc welding with a consumable electrode in a shielding gas environment, containing a nozzle and a current-conducting mouthpiece located inside it with a housing in which a contact tip protruding from the nozzle is installed, and an element for creating a laminar the flow of the protective gas, as well as the chamber for heating gasification with liquid C0 (^, formed by the inner surface of the nozzle and the outer surface of the mouthpiece. In the mouthpiece of the burner a recess, forming with the nozzle walls, a collector located above the chamber for heating and gasification of liquid COq · The collector is connected to the chamber by channels for reducing liquid C0 (c. The channels are made in the form of grooves on the surface of the mouthpiece [3] ·

However, in such a burner splashing. drops of molten metal of the gas-permeable nozzle insert with a long arc welding time limits the burner continuous operation and shortens its service life, and metal spatter welded to the cells of the gas-permeable nozzle insert cannot be removed without breaking the surface layer of the gas-permeable insert.

The aim of the invention is to increase the life of the burner by reducing its splashing drops of molten metal.

This goal is achieved by the fact that in a torch for arc welding with a consumable electrode in a shielding gas medium containing a nozzle and a current-conducting mouthpiece located inside it with a housing in which a contact tip protruding from the <nozzle and an element for creating a laminar outflow of the protective gas stream are installed, as well as a chamber for heating and gasification with liquid COq_ formed by the inner surface of the nozzle and the outer surface of the mouthpiece, the element for creating a laminar outflow of the protective gas stream is made in the form of a collar with holes along its perimeter located on the working end of the mouthpiece, and the protruding end of the contact tip 5 is made in the form of two coaxial cones with vertices pointing in opposite directions and a common base, the diameter of which is equal to the inner diameter of the nozzle.

Figure 1 shows the burner, a General view (first option); in Fig.2 section of the burner aa in Fig.1; in Fig. 3 “burner (second option).

The burner contains a current supply 15 mouthpiece with a housing 1 with a channel for guiding the consumable electrode and a contact tip 2 screwed into the housing 1, protruding from the nozzle 3 pressed onto the mouthpiece.

The protruding end of the contact tip is made in the form of biaxial cones with vertices directed in opposite directions and a common base. The burner has a chamber 4 for heating and gasification of the liquid C0 ^ coupled to SOcherez liquid supply system a reducing device 5. The chamber 4 for heating and gasification of the liquid CO ^ Obra 0 ₃ 6 Call annular groove on the lateral wail surface of the mouthpiece body.

The working end of the body 1 of the mouthpiece is made with a collar /. Playing the role of a $ 3 element to create a laminar flow of the protective gas.

An annular groove 6 and a shoulder 7 of the mouthpiece are machined on a lathe. In the burner shown in FIG. 1, the annular groove 6 and the shoulder 7 ′ are perpendicular to the axis of the mouthpiece, in the burner shown in FIG. 3, they are located at an angle to the axis of the mouthpiece. To supply shielding gas to the welding zone, ⁴⁵ through holes 8 with a diameter of 0.5

1.2 mm in concentric circles. The gas-permeable collar 7 can be made by powder metallurgy in the form of a porous ring of ⁵⁰ centigrade, followed by pressing it onto the working end of the case’s mouthpiece 1. To prevent splashing of the collar metal 7 with drops, the diameter of the base of the conical end of the contact55 tip 2 is equal to the inner diameter of the nozzle 3 (the outer diameter of the collar is equal to the inner diameter of the nozzle).

933327 6

The casing 1 of the current-carrying mouthpiece, the contact tip 2 and the reducing device 5 are made of copper or alloys with high electrical conductivity, the nozzle 3 is made of ⁵ photoplastic, carbon fiber, or other heat-resistant electrically insulating materials. The housing 1 is insulated externally with a layer of heat-resistant coating, for example aluminum oxide, or a tube of heat-resistant rubber. In order to reduce burner spraying and to prevent contact tip 2 from shorting to the product, its outer surface 15 can be coated with a layer of heat-resistant coating, for example zirconia, alumina.

In the process of welding, liquid CO ^ enters the torch under high pressure (up to 75 kgf / cm ^) under pressure (up to 75 kgf / cm ^), passing through the reducing device 5, is throttled to a pressure of 1 kgf / cm ^ and then supercooled to -78 ° C enters 25 for heating and gasification in the chamber,

4 formed by the cavity of the annular groove 5 of the mouthpiece body and the adjacent inner surface of the nozzle 3. At the same time, the tip 2 with the conical protruding end is heated from the radiation behind and heat transfer of the arc, from which heat is transferred to the shoulder 7 and the mouthpiece c due to its high thermal conductivity. _{35 by the} groove 6. The supercooled liquid CO ^ (dry ice), in contact with the heated surface of the groove 6, is intensely gasified and heated, taking away heat and creating in the chamber ₄₀ 4 the excess pressure necessary to overcome the gas-dynamic resistance of the shoulder 7 of the mouthpiece body. Under the action of excess pressure, C0 ^ passes through the openings _4J 8 of the collar 7, additionally heats up, forms in the form of a multilayer gas-shielding flow, and enters the welding zone. After the arc breaks, after a few seconds, the liquid supply 00 ^ automatically stops due to filling of the mouthpiece groove 6 of the mouthpiece with dry ice and overlapping of the calibrated opening of the reducing device

5. To resume the gas supply to the burner, it is enough to light the arc between the consumable electrode and the product. The heating of the contact tip 2 and the body 1 of the mouthpiece from arc radiation will cause the freezing of dry ice and heating of gaseous С0 ^ in the groove 6 of the mouthpiece, and the burner operation cycle will begin to repeat.

Thus, in the proposed device, an annular groove on the outer surface of the mouthpiece body together with a gas-permeable collar located on the lower end part of the mouthpiece, and connected through a reducing device with a liquid CO <j supply system, serves as a heating and gasification chamber for liquid С0 (£, device - to form a flow of protective gas and economizer COq_.

The design of the proposed burner is simplified, and the labor and expense of non-ferrous metals for the manufacture of wearing standard nozzles are reduced.

The presence of a cone-shaped end of the contact tip and its intensive cooling with liquid С0 <^ make it possible to exclude droplet splashing of the gas-conducting channels and the gas-permeable collar of the mouthpiece, which makes it possible to increase the time of continuous operation of the burner.

The torch design provides reliable multi-layer protection of the weld zone from exposure to air.

Claims (1)

3 9 arcs, and the inefficient use of liquid COfj to cool the heating parts of the burner, since the reduction of the supercooled to -78 ° C liquid CUQ is supplied to the burning zone of the arc. The closest to the technical essence and the achieved effect to the invention is a torch for arc welding with a melting electrode in a protective gas environment, comprising a nozzle and a current-conducting die located inside it with a housing in which a contact tip protruding from the nozzle is installed, and creating a laminar flow of protective gas flow; and a chamber for heating gasification with liquid COrj formed by the inner surface of the nozzle and the outer surface of the mouthpiece. In the mouthpiece of the burner, a recess is formed, forming with the walls of the nozzle, a collector located above the chamber for heating and gasifying liquid CO. The collector is connected to the chamber by channels for reducing the liquid SOP. The channels are made in the form of grooves on the surface of the mouthpiece 3. However, there is spattering in such a burner. When melting metal drops of a gas-permeable nozzle insert, when the arc welding time is long, it limits the burner's continuous operation time and shortens its service life. Metal splashes welded to the cells of the gas-permeable nozzle insert cannot be removed without destroying the surface layer of the gas-permeable insert. The aim of the invention is to increase the service life of the burner by reducing splashing with drops of molten metal. This goal is achieved by the fact that in a torch for arc welding by a melting electrode in a protective gas medium containing a nozzle and a current-carrying die located inside it with a housing in which a contact tip protruding from the nozzle is installed, and an element for creating a laminar flow of protective gas, as well as a chamber for heating and gasification of liquid COQ, formed by the inner surface of the nozzle and the outer surface of the mouthpiece, the element for creating a laser discharge of protective gas is made in the form of a collar holes along its perimeter, located on the working end of the mouthpiece, and the protruding end of the contact tip is made in the form of two coaxial bosses with vertices directed in opposite directions, and a common base, the diameter of which is equal to the inner diameter of the nozzle. Fig. 1 shows a burner, a general view of the first variant; Fig.2section of the burner aa in Fig.1; fig. 3 - burners (second variant. The burner contains a current-carrying mouthpiece with a housing 1 with a channel for guiding the melting electrode and screwed into the housing 1 with a contact tip 2 projecting from the nozzle pressed on the mouthpiece 3. The projecting end of the contact tip is made in the form of two - coaxial cones with vertices directed in opposite directions and a common base. The burner has a chamber k for heating and gasification of liquid SOL, connected to the power supply system of liquid C0i2 through a reducing device 5. The chamber k for reheating and gasifying the liquid CO with a ring groove 6 on the side surface of the mouthpiece body. The working face of the body 1 of the mouthpiece is made with a collar 7 "playing the role of an element for creating a laminar flow of protective gas. The ring groove 6 and the collet 7, the mouthpiece is machined. In the burner shown in Fig. 1, cola 4 yva groove 6 and shoulder 7 perpetuator} are aligned with the axis of the mouthpiece, in the burner shown in fig. 31 they are rotated at an angle to the axis of the mouthpiece. To supply the protective gas to the welding zone, through holes of a diameter of 0.5–1.2 mm along concentric circles are drilled in the wall of the collar 7. The gas-permeable shoulder 7 can be made by powder metallurgy in the form of a porous ring, followed by pressing it onto the working end of the body1 of the mouthpiece. In order to prevent dropping of metal of the collar 7, the diameter of the base of the cone-shaped end of the contact tip 2 is made equal to the inner diameter of the nozzle 3 (the outer diameter of the collar is equal to the inner diameter of the nozzle). 5 The body 1 of the current-carrying mouthpiece, the contact tip 2 and the reducer device 5 are made of copper or alloys with high electrical conductivity, the nozzle 3 is made of a photo-plastic, carbon plastic or other heat-resistant electrically insulating materials. The housing 1 is insulated externally with a layer of heat-resistant coating, such as alumina, or a tube of heat-resistant rubber. In order to reduce the spattering of the burner and eliminate the closure of the contact device, nechnik 2, to the product, its outer surface may be covered with a layer of heat-resistant coating, for example, zirconia, alumina. during welding, liquid CO2 enters the torch under high pressure (up to 75 kgf / cm) from the supply line, the passage through the reducing device 5, is throttled to a pressure of 1 kgf / cm - and then supercooled to -78 ° C is fed for heating and gasification in chambers 4 formed by the cavity of the annular groove I of the mouthpiece body and the adjacent inner surface of the nozzle 3- At the same time, the tip 2 is heated from the radiation and heat transfer of the arc, with a conical lug that ends due to its high thermal conductivity with heat on collet 7 and mouthpiece with groove 6. Supercooled liquid Cop dry ice), in contact with the heated surface of groove 6, is intensively gasified and heated, extracting heat and creating excessive pressure in the chamber k to overcome the gas-dynamic resistance of collar 7 of the mouthpiece body . Under the action of overpressure, the SOL passes through the apertures j b of the collar 7, additionally heats up and forms as a multilayer gas-shielding flow and goes to the welding zone. After a break in the arc, after a few seconds, the flow of liquid CO automatically stops, due to filling the groove 6 of the mouthpiece with dry ice and blocking the calibrated orifice of the reducing device 5. To resume gas supply to the burner, it is enough to ignite the arc between the melting electrode and the product. Heating the contact tip 2 and the mouthpiece body 1 from the radiation of the arc will cause sublimation of dry ice and heating of the gaseous SOP in the bore 6 of the mouthpiece, and the burner cycle will begin to repeat. Thus, in the proposed device, an annular groove on the outer surface of the mouthpiece body together with a gas-permeable collar located at the lower end part of the mouthpiece, and connected through a reducing device to the liquid feeding system C0 (j, functions as a heating chamber and gasification of the liquid Sop device). to form a flow of shielding gas and an COQ economizer. The design of the proposed burner is simplified, and the labor costs and consumption of non-ferrous metals for the manufacture of wear-down standard nozzles The cone-shaped end of the contact tip and its intensive cooling with liquid COO make it possible to avoid spattering metal droplets of gas-conducting channels and a gas-permeable collar of the mouthpiece with drops, which makes it possible to increase the time of continuous operation of the burner. of the invention of a torch for arc welding with a melting electrode in a shielding gas environment, ss holding the nozzle and the current lead inside it with a housing in which a contact tip protrudes from the nozzle and an element for creating a laminar flow of protective gas, as well as a chamber for heating and gasification with liquid 0, formed by the inner surface of the outer surface of the nozzle which mounts the mouthpiece, according to which In order to increase the service life of the burner by reducing its splashing with droplets of molten metal, the element for creating a laminar flow of a protective flow, the gas is made in the form of a collar with holes along its perimeter, It is provided at the working end of the mouthpiece body, and the protruding end of the contact tip is made in the form of two coaxial cones with vertices.