Double-shielded TIG welding method

Abstract

To provide a double shield tig welding method, which can perform welding stably while making flow rates of inner gas and outer gas proper under a variety of welding conditions.SOLUTION: A double shield tig welding method, which performs welding by generating an arc 3 between an electrode 1 and a base material 2 and passing welding currents Iw, using a welding torch WT provided with an inner nozzle 4 that jets inner gas 7 and an outer nozzle 5 that jets outer gas 9, sets a flow rate Fi of the inner gas and a flow rate Fo of the outer gas, in accordance with a value of the welding currents Iw, and corrects the set flow rate Fi of the inner gas and / or the set flow rate Fo of the outer gas, in accordance with a diameter H1r of the electrode, a material quality H2r of the base material and a joint shape H3r of the base material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a double-shielded TIG welding method. [Background Art]

[0002] A double-shielded TIG welding method in which welding is performed using a welding torch provided with an inner nozzle for ejecting inner gas and an outer nozzle for ejecting outer gas is commonly used (see, for example, Patent Document 1). As the inner gas and the outer gas, inert gases such as argon and helium are used. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2020-15048 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In the double-shielded TIG welding method, if the flow rates of the inner gas and the outer gas are not appropriate, the welding state may become unstable or shielding defects may occur.

[0005] Accordingly, an object of the present invention is to provide a double-shielded TIG welding method that enables stable welding by optimizing the flow rates of the inner gas and the outer gas under various welding conditions. [Means for Solving the Problem]

[0006] In order to solve the above problem, the invention of claim 1 is: using a welding torch provided with an inner nozzle for ejecting inner gas and an outer nozzle for ejecting outer gas, in the double-shielded TIG welding method in which an arc is generated between an electrode and a base material and a welding current is supplied to perform welding, The flow rates of the inner gas and the outer gas are set according to the value of the welding current. The flow rates of the inner gas and / or outer gas, which are set according to the diameter of the electrode, the material of the base material, and the joint shape of the base material, are corrected. This is a double-shielded TIG welding method characterized by the following features.

[0007] The invention of claim 2 is, The above correction reduces the flow rate of the inner gas as the diameter of the electrode decreases, while keeping the flow rate of the outer gas unchanged. The double-shielded TIG welding method according to feature 1.

[0008] The invention of claim 3 is, The above correction increases the flow rate of the outer gas when the base material is aluminum compared to when it is steel, while keeping the flow rate of the inner gas unchanged. The double-shielded TIG welding method according to feature 1.

[0009] The invention of claim 4 is, The above correction increases the flow rate of the inner gas when the joint shape is a fillet joint compared to when it is a butt joint, while keeping the flow rate of the outer gas unchanged. The double-shielded TIG welding method according to feature 1. [Effects of the Invention]

[0010] According to the double-shielded TIG welding method of the present invention, the flow rates of the inner gas and outer gas can be optimized under various welding conditions, thereby enabling stable welding. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram of a welding apparatus for implementing a double-shielded TIG welding method according to an embodiment of the present invention. DESCRIPTION OF EMBODIMENTS

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a block diagram of a welding apparatus for carrying out a double-shielded TIG welding method according to an embodiment of the present invention. Each block will be described below with reference to this figure.

[0014] A welding torch WT mainly includes an electrode 1, an inner nozzle 4 surrounding the electrode 1, and an outer nozzle 5 surrounding the inner nozzle 4. A tungsten electrode or the like is used for the electrode 1. For example, the inner diameter of the inner nozzle 4 is 5 mm, and the inner diameter of the outer nozzle 5 is 13 mm.

[0015] A start switch ON outputs a start signal On that becomes a High level when turned on and becomes a Low level when turned off. This start switch ON is a torch switch provided on the welding torch WT. In some cases, the start signal On is output from a robot control device.

[0016] A current setting circuit IR outputs a predetermined current setting signal Ir.

[0017] An electrode diameter correction circuit H1R outputs an electrode diameter correction signal H1r that satisfies: when the diameter of the electrode 1 to be used is selected from 1.6 mm, 2.4 mm, or 3.2 mm, H1r=-1 if 1.6 mm is selected, H1r=-0.5 if 2.4 mm is selected, and H1r=0 if 3.2 mm is selected.

[0018] A base material material correction circuit H2R outputs a base material material correction signal H2r that satisfies: when the material of the base material 2 to be used is selected from steel or aluminum, H2r=0 if steel is selected, and H2r=2 if aluminum is selected.

[0019] When either a butt joint or a fillet joint is selected for the joint shape of a base material 2, the joint shape correction circuit H3R outputs a base material joint correction signal H3r that becomes H3r=0 when a butt joint is selected, and becomes H3r=1 when a fillet joint is selected.

[0020] An inner gas flow rate setting circuit FIR receives the aforementioned current setting signal Ir, the aforementioned electrode diameter correction signal H1r and the aforementioned joint shape correction signal H3r as inputs, inputs them into a predetermined inner gas flow rate setting function, and outputs a value calculated thereby as an inner gas flow rate setting signal Fir [l / min]. An example of the inner gas setting function is shown below. Fir=(Ir-75) / 50+3.5+H1r+H3r Equation (1) Provided that Ir is within the range of 75≦Ir≦150; when Ir<75, the same value as Ir=75 is applied; when Ir>150, the same value as Ir=150 is applied.

[0021] An inner gas flow rate regulator CI is a conventionally used mass flow controller, which receives the aforementioned start signal On and the aforementioned inner gas flow rate setting signal Fir as inputs, and when the start signal On becomes a High level, adjusts the flow rate Fi of inner gas 7 from an inner gas cylinder 6 to a value determined by the inner gas flow rate setting signal Fir and ejects the inner gas.

[0022] An outer gas flow rate setting circuit FOR receives the aforementioned current setting signal Ir and the aforementioned base material property correction signal H2r as inputs, inputs them into a predetermined outer gas flow rate setting function, and outputs a value calculated thereby as an outer gas flow rate setting signal For [l / min]. An example of the outer gas setting function is shown below. For=(Ir-75) / 50+5.5+H2r Equation (2) Provided that Ir is within the range of 75≦Ir≦150; when Ir<75, the same value as Ir=75 is applied; when Ir>150, the same value as Ir=150 is applied.

[0023] The outer gas flow regulator CO is a conventional mass flow controller that takes the above-mentioned activation signal On and the above-mentioned outer gas flow rate setting signal For as inputs. When the activation signal On reaches a high level, it adjusts the flow rate Fo of the outer gas 9 from the outer gas cylinder 8 to a value determined by the outer gas flow rate setting signal For and then dispenses it.

[0024] Inner gas 7 flows through the passage inside inner nozzle 4. Outer gas 9 flows through the passage outside inner nozzle 4 and inside outer nozzle 5. Inert gases such as argon and helium are used for inner gas 7 and outer gas 9. Arc 3 is generated with electrode 1 as the negative electrode and base material 2 as the positive electrode.

[0025] The welding power supply PS receives the above-mentioned start signal On and current setting signal Ir as inputs. When the start signal On reaches a high level, it applies a high-frequency high voltage between electrode 1 and base material 2. When arc 3 is generated, it starts outputting the welding current Iw set by the current setting signal Ir. When the start signal On reaches a low level, it stops outputting the welding current Iw.

[0026] The following describes numerical examples of setting the flow rates of the inner and outer gases according to the welding current value, and correcting the flow rates of the inner and / or outer gases according to the electrode diameter, the material of the base material, and the joint shape of the base material. (1) Correction of inner gas flow rate Electrode diameter 3.2mm → Electrode diameter correction signal H1r=0 Joint shape: Butt joint → Joint shape correction signal H3r=0 From equation (1) above, the inner gas flow rate Fi is given by inputting the current setting signal Ir. Since Fi = (Ir - 75) / 50 + 3.5 + H1r + H3r, When Ir = 75A, Fi = 3.5 (l / min), When Ir = 150A, Fi = 5 (l / min). Here, when the electrode diameter becomes 2.4 mm, the electrode diameter correction signal H1r becomes -0.5, The inner gas flow rate Fi will be 0.5 (l / min) smaller than in the above case. When the electrode diameter becomes 1.6 mm, the electrode diameter correction signal H1r becomes -1, The inner gas flow rate Fi will be 1 (l / min) smaller than in the above case. When the joint shape becomes a fillet joint, the shape correction signal H3r becomes 1, The inner gas flow rate Fi will be 1 (l / min) greater than the value in the above case.

[0027] (2) Correction of outer gas flow Base material: Steel; Base material correction signal H2r=0 From equation (2) above, the outer gas flow rate Fo is obtained by inputting the current setting signal Ir. Since Fo = (Ir-75) / 50 + 5.5 + H2r, When Ir = 75A, Fo = 5.5 (l / min), When Ir = 150A, Fo = 7 (l / min). Here, when the base material is aluminum, the base material correction signal H2r becomes 2, The outer gas flow rate Fo will be 2 (l / min) higher than in the above case.

[0028] The effects and advantages of this embodiment will be described below. According to this embodiment, the flow rates of the inner gas and outer gas are set according to the welding current value, and the flow rates of the inner gas and / or outer gas are corrected according to the electrode diameter, the material of the base material, and the joint shape of the base material. In this way, in this embodiment, the flow rates of the inner gas and outer gas are automatically optimized according to various welding conditions such as the welding current value, electrode diameter, material of the base material, and joint shape of the base material, so that stable welding can be performed.

[0029] Furthermore, according to this embodiment, the correction reduces the flow rate of the inner gas as the electrode diameter decreases, while keeping the flow rate of the outer gas unchanged. In this way, even if the electrode diameter changes, the flow rates of the inner and outer gases are automatically optimized, enabling stable welding.

[0030] Furthermore, according to this embodiment, the correction increases the flow rate of the outer gas when the base material is aluminum compared to when it is steel, while keeping the flow rate of the inner gas unchanged. In this way, even if the base material changes, the flow rates of the inner and outer gases are automatically optimized, enabling stable welding.

[0031] Furthermore, according to this embodiment, the correction increases the inner gas flow rate when the joint shape is a fillet joint compared to a butt joint, while keeping the outer gas flow rate unchanged. In this way, even if the joint shape of the base material changes, the inner and outer gas flow rates are automatically optimized, enabling stable welding. [Explanation of Symbols]

[0032] 1 electrode 2 Base material 3 Arc 4. Inner nozzle 5. Outer nozzle 6. Inner gas cylinder 7 Inner gas 8. Outer gas cylinder 9 Outer gas CI Inner Gas Flow Regulator CO Outer Gas Flow Regulator Fi Inner gas flow rate FIR Inner Gas Flow Rate Setting Circuit Fir Inner Gas Flow Rate Setting Signal Fo Outer gas flow rate FOR Outer Gas Flow Rate Setting Circuit For outer gas flow rate setting signal H1R electrode diameter correction circuit H1r electrode diameter correction signal H2R base material correction circuit H2r Base material correction signal H3R Joint Shape Correction Circuit H3r joint shape correction signal IR current setting circuit Ir current setting signal Iw welding current ON Start switch On activation signal PS welding power supply WT welding torch

Claims

1. Using a welding torch equipped with an inner nozzle for ejecting inner gas and an outer nozzle for ejecting outer gas, In a double-shielded TIG welding method in which an arc is generated between the electrode and the base material and a welding current is passed through to perform welding, The flow rates of the inner gas and the outer gas are set according to the value of the welding current. The flow rates of the inner gas and / or outer gas, which are set according to the diameter of the electrode, the material of the base material, and the joint shape of the base material, are corrected. A double-shielded TIG welding method characterized by the following features.

2. The above correction reduces the flow rate of the inner gas as the diameter of the electrode decreases, while keeping the flow rate of the outer gas unchanged. The double-shielded TIG welding method according to feature 1.

3. The above correction increases the flow rate of the outer gas when the base material is aluminum compared to when it is steel, while keeping the flow rate of the inner gas unchanged. The double-shielded TIG welding method according to feature 1.

4. The above correction increases the flow rate of the inner gas when the joint shape is a fillet joint compared to when it is a butt joint, while keeping the flow rate of the outer gas unchanged. The double-shielded TIG welding method according to feature 1.

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