GYS Welding Training TIG

Updated 05.05.2021

WELDING

TIG

t. i . G

Tungsten Inert Gas TIG welding is an inert gas shielded arc process with an infusible tungsten electrode.

Welding is based on an electric arc created and maintained between the tungsten electrode and the workpiece. It is a precision process that allows welding on even very thin sheets.

(GTAW)

AC current : alternating current used for welding aluminium and its alloys (CuAl Nickel).

This material requires an AC current to strip the alumina, a thin layer on the surface of the aluminium (melting point : 2100°C), before you can weld the part (melting point : 660°C).

DC current : direct current used for welding steel, stainless steel, copper and brass.

Process principle

Gas supply Torch

The electric arc is formed under gas protection between the wire and the part to be welded, resulting in their fusion. The weld pool is protected from the outside air by the protective gas.

Nozzle Tungsten electrode Filler metal Protection gas Electric arc Weld pool Weldbead

Applications

Industry food-processing industry

Chemical industry

Aerospace

ADVANTAGE S • Suitable for most materials • Good appearance of welds • Filler metal not always necessary • Penetration control • Welding in all positions.

• Welding thin layers 4/10 mm

Shipbuilding

Pipework

Repair & maintenance

DISADVANTAGE S • Low productivity on thickness > 4 mm • Difficult/impossible outdoor work • Good control of movements is essential • High cost of welding (gas, tungsten electrode) • Requires a qualified welder

WELDING

TIG

Material and preparation steps Equip the welding machine with a gas cylinder and pressure regulator. The current to be used depends on the material :

Equipment required for TIG welding :

Argon + H : stainless steel welding Pure argon : soudage inox, acier, aluminium Argon + Helium 30% : aluminium welding (ideal for heavy thicknesses)

Regulator

Equipment

Earth clamp

To use a TIG welding machine, it is necessary to equip it : - a cylinder of inert gas (Argon) - a pressure reducer - a TIG torch - an earth clamp to be connected to the + pole.

Set up 1. Extend the tungsten electrode by 5 mm.

2. Select the TIG function on the unit.

3. Adjust the gas flow rate on the pressure regulator

Torch

of the gas cylinder.

4. Tungsten electrode sharpening: NB: Circular striations favour an unstable bow, while lengthwise striations increase the stability of the bow.

Cooling system (if water-cooled torch)

Protection gas

30˚ - 60˚ Ø x 2,5

Power source

Perpendicular grinding Circular striations

Parallel grinding Longitudinal striations

Protective equipment & consumables Torch consumables

Before any welding activity, be sure to wear protective equipment :

Nozzle

Welding helmet

Protective gloves

Apron or protective suit

Safety shoes

Fume extraction

Consumables TIG filler metals can be added during welding to strengthen the joint.

Selection criteria: - Material e.g.: steel - Filler metal diameter e.g.: Ø 1.6 ou 2 mm Indusible ungsten electrodes are placed inside the torch to create the electric arc.

Selection criteria: - Process e.g.: AC/DC - Electrode diameter e.g.: Ø 1.6 mm

Diffuser Insulating ring

Torch body

Double button Options - Valve - Potentiometer - Trigger

Earth clamp electrode holder Grip handle

head cover

Ball joint

WELDING

tig

Abacus In order to obtain a good quality weld, the user must adjust his machine according to the type of joint and the thickness.

SHEET THICKNESS

ELECTRODE DIAMETER (mm)

INTENSITY (A)

1 1.5 2 3 4

1.2 1.6 1.6 2.4 2.4

30 40 60 / 70 100 / 120 110 / 130

INTERIOR ANGLE

1 1.5 2 3 4

1.2 1.6 1.6 2.4 2.4

30 70 60 / 70 100 / 120 110 / 130

OVERLAP

1 1.5 2 3 4

1.2 1.6 1.6 2.4 2.4

30 70 80/90 100/120 110/130

1 1.5 2 3 4

1.2 1.6 1.6 2.4 2.4

30 70 70 / 80 110 / 120 130 / 150

TYPE OF JOINTS

(mm)

TOE TO TOE

INTERIOR ANGLE

GAS FLOW (l/min)

10 to 12

10 to 12

8 to 12

6 to 10

INSIDE OF NOZZLE (mm)

FILLER METAL DIAMETER (mm)

10 to 19

1.2 1.2 / 1.6 1.6 2.4 2.4

10 to 19

1.2 1.2 / 1.6 1.6 2.4 2.4

8 to 19

1.2 1.2 / 1.6 1.6/2 2.4 2.4

6 to 19

1.2 1.2 / 1.6 1.6 / 2 2.4 2.4

The welding current can be increased by (+/-20 A) depending on your welding speed. Increasing the welding speed will reduce the deformation of the sheets.

Ignition modes TIG Lift "Touch" the workpiece, then lift the electrode to start the arc. electrode and the weld. Suitable for areas sensitive to electromagnetic fields (e.g. areas with electronic devices: pressure sensors, temperature sensors etc.).

HF (Hugh Frequency) - The easiest way to prime.

- An electric arc is created by simply pressing the torch button after positioning the torch a few millimetres from the workpiece.

- HF consists of a voltage peak of several thousand volts per second.

- Not suitable for areas sensitive to electromagnetic fields (hospitals, etc.).

Touch HF Mixture of TIG Lift and HF mode. The user touches the workpiece with the tungsten electrode. Then, by raising the electrode, the "HF" is activated and creates the arc. This ignition mode ensures high accuracy and repeatability of ignition.

Touch HF video

WELDING

TIG

Choosing the right TIG welding machine Welding current (A) TIG MMA MMA CEL AC HF PULSE PULSE

5

10 35 40 60 80 100 120 140 160 180 200 220 250 300 350 400

Integrated

FV

PFC IP23 VRD

cooling unit

Single-phase TIG 160 DC Lift

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PROTIG 161 DC HF

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PROTIG 200 DC HF

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PROTIG 201 DC HF FV

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PROTIG 201 AC/DC

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PROTIG 201 L AC/DC

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TIG 220 DC HF

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TIG 220 AC/DC HF

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TIG 250 AC/ DC HF

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TIG 300 DC HF

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TITAN 400 DC

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TITANIUM 400 AC/DC

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AC DC AC DC

AC DC

Three-phase AC DC

AC DC

Welding parameters Trigger mode

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+

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2T Press and hold the trigger to weld. Release the trigger to stop welding.

4T Press and release the trigger to weld. Press and release the trigger to stop welding.

TIG

Standard welding

TIG SPOT

Each pull of the trigger creates a weld point (ideal for securing sheet extremities before welding). This function deactivates the "Up Slope" and "Down Slope" phases.

TIG PULSE

Impulse welding (limits the deformation of the workpiece due to heat. E.g.: pipework).

Pre gas

The gas is diffused before the arc is created in order to create the gas shield.

Up Slope

Time needed to go from minimum current to welding current (smoother current rise).

Cold current pulse

Determines the cold current, which is a percentage of the displayed setpoint: "hot current" (TIG Pulse mode).

Pulse frequency

Determines the time between each pulse (TIG Pulse mode).

Down Slope

Time needed at the end of the weld to reduce the current (avoids craters at the end of the weld).

Post Gas

The time required to protect the weld pool and electrode during cooling at the end of the welding process.

AC frequency

Determines the number of alternations per second.

AC balance

The scale allows the ratio between positive (pickling) and negative ( welding-penetration) cycles to be adjusted.