SK147498A3 - Method for controlling arc welding process with consumable electrode in an gaseous protection with aim to secure constant distance of welding torch from basic material - Google Patents

Abstract

A minimum value of the electric resistance of the welding wire between a contact tip and basic material in the moment of a short circuit of the electrodes is a controlable value of the distance between the torch and material. Real value and the deviation of said controlable parameter from a desired value, or the intervals thereof, is measured in the moment of the short circuit, thus indicating that a correction of the position between the torch and basic material needs attention.

Description

Method for controlling the arc welding process with a melting electrode in gas protection to ensure a constant distance of the welding torch from the base material

Technical field

The invention relates to a method for controlling an arc welding process with a melting electrode in gas protection (GMA welding) with short-circuit transfer of metal from the electrode to the weld bath to ensure a constant distance of the welding torch from the base material.

In order to achieve quality welding joints of constant performance properties during GMA welding, it is necessary to ensure constant parameters and welding conditions throughout the implementation of the welding process. Under real conditions of welding, however, a number of different positional fault variables enter the welding process, the origin and intensity of which is influenced especially by inaccuracies of welding edges preparation, deviations in clamping and positioning of welded parts, thermal deformation of parts during welding etc. The basic requirement for GMA arc welding is therefore to ensure a constant distance between the welding torch and the surface of the base material along the entire weld joint. The burner-material distance can be defined primarily by the distance of the tip of the contact tip from the surface of the base material. This is because the trip of the electrode and the length of the welding arc, which largely influence the stability of the arc burning, the width of the plasma beam at the location of the welding bath, the depth of the weld and the formation of the weld bead, depend on this quantity.

BACKGROUND OF THE INVENTION

The current GMA arc welding methods solve the problem of positioning the torch relative to the surface of the base material by mechanisms,

- who are unable to correct real-time positional variables, i. during the welding process. In general, these are only freely programmable positioning mechanisms that are not equipped with an adaptive positioning correction system.

Positioning of the welding torch with respect to the machine base material. · Arc welding GMA poses a significant technical problem. Most of the proposed solutions of adaptive position correction systems generally have only very limited use, respectively. is only applicable to a very narrow field of industrial applications. These are in particular known corrective adaptive positioning systems operating on the principle of measuring the burner-material distance by means of tactile, inductive, capacitive and optical position sensors. However, the harsh working environment, such as high temperature, strong interfering electromagnetic field, intense light radiation, spatter of metal etc. In order to approach the position of the measurement site to the point of formation of the weld bead (welding bath), the adaptive positioning systems are positioned in the immediate vicinity of the welding torch and the welding arc, but on the other hand significantly reducing the sensitivity, accuracy and durability of the elements used.

SUMMARY OF THE INVENTION

These disadvantages are largely eliminated by the proposed method of GMA arc welding control in order to ensure a constant distance t

welding torch away from the surface of the base material. The principle of the invention is that a minimum value of the electrical resistance of the welding wire between the contact tip and the base material during the short-circuit of the electrodes is used to measure the torch-to-material distance in real time. In an adaptive position correction system, this parameter represents the controlled variable. During GMA welding, the actual value of the controlled variable and its deviation from

The setpoint, or setpoint interval, instructs the position of the welding torch relative to the base material.

The advantages of the proposed method of ensuring a constant distance of the welding torch from the base material surface in GMA_sn arc welding by metal short-circuit transfer is that the torch-material distance sensor is the actual welding wire, eliminating the mentioned disadvantages of tactile, capacitive, inductive and optical sensors.

DETAILED DESCRIPTION OF THE INVENTION

The proposed method of ensuring a constant distance of the welding torch from the surface of the base material and engaging the method has been tested for arc welding of GMA shaped and large-size 10 mm carbon steel parts in CO2 protection under the following welding parameters and conditions: welding current 165 A , wire feed speed 4 m / min, welding wire diameter 1.2 mm, successive welding speed 5 mra / s, torch-material distance 14 mm, static characteristics of CP source, dynamic characteristics of source 60kA / s, shielding gas flow 15 1 / min. Using the proposed method of ensuring a constant torch-material distance it was possible to achieve a reliable height copying of the base material surface with a welding torch, thus achieving a constant torch-material distance and uniform formation of the weld bead when the base material inclined to the horizontal plane within ± 17 °. without the proposed method of ensuring a constant distance between the torch and the material at a 17 ° inclination, the welding process had to be interrupted after a few centimeters of the weld due to a mechanical collision of the torch with the base material.

-4Default usability

The proposed method of ensuring a constant distance of the welding torch from the surface of the base material can be advantageously used especially in machine, automated and robotized arc welding with a melting electrode in gas protection under conditions where the metal is short-circuited from the wire to the welding bath. , mixtures of CCh + Ar and Ar at low parameters.

Claims (2)

PATENT CLAIMS A method of controlling an arc welding process with a melting electrode in a gas shield to provide a constant distance between the welding torch and the surface of the base material, characterized in that the controlled magnitude of the torch-material distance through the contact tip and base material during shorting of the electrodes. Method according to claim 1, characterized in that during welding the actual value of the controlled quantity is measured and its deviation from the setpoint or setpoint interval, instructs to correct the distance of the welding torch to the base material.