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Welding is a technological process in which a large number of parameters and factors must be taken into account. The greatest control over welding characteristics is required for TIG arc welding with a non-consumable electrode in inert gas shielding. Therefore, to simplify the control of a number of parameters in welding inverters, a cyclogram is used.

With the help of cyclogram the welder sets the necessary welding parameters so that the process does not cause difficulties, as well as to prevent various defects. Let’s consider the cyclogram of the welding machine.

How does the cyclogram affect the setup process of TIG machines?

Each parameter of the cyclogram is important, so in order to obtain high-quality welded joints, it is necessary to understand why it is needed and how to set it up. Let’s analyze each of them in detail.

Time of gas supply before welding

This is a parameter that increases the delay time of the high-frequency oscillator, while the gas valve in the machine is in the open position, thereby supplying shielding gas to the torch. Typically has an adjustment range of 0.1 to 10-15 seconds. Adjusting this parameter allows you to expel from all channels of argon-arc torch excess oxygen so that it did not get into the welding zone and did not fill the weld seam with vapors, because inert gases are heavier than air and displace oxygen from the welding zone.

Tip. The recommended gas supply time is 1.0 to 2.0 seconds. This is enough to expel air from all channels and not to waste shielding gas.

Starting current

A parameter that allows you to set the welding current at the beginning of welding. Warms the edges of the metal to be welded evenly to produce a weld pool and subsequent insertion of filler rod. Typically has a range of 5-15 amps up to the maximum welding current of the machine.

Current rise time

A parameter that can be used to control the time it takes for the welding current to change from the starting current to the main (peak) current. This parameter is of particular importance when welding thick metal, when the edges are already heated, but the welding current is not strong enough to produce a weld pool. The adjustment range is from 0.1 seconds to 10-15 seconds.

Peak current

The peak current for non-pulsed arc welding is the main welding parameter that forms the weld pool and the weld seam. In pulsed arc welding, it is the upper limit of the welding current that also forms the weld seam. Usually has a range from 5-15 amperes to the maximum value of the welding current of the machine.

Tip. Start current is better to set more peak (main) current at 10-20 Ampere to quickly form a weld pool without further overheating of the base metal. It is better to set the current drop time from 1.5 to 2.0 seconds, so as not to heat the metal for a long time and not to get burned.

Base current

An indicator that, in combination with the peak current, gives a pulsed arc with a certain frequency that can be adjusted. The base current sets the lower limit of the pulse. It is used when welding thin sheet metal to prevent overheating, burnout of alloying elements, scorching and warping. The base current helps keep the weld pool from failing and from scorching. The standard adjustment range is from 5-15 Amps to the maximum welding current of the machine.

This parameter will only be active in AC Pulse and DC Pulse mode, i.e. pulse arc welding, in other modes this parameter will not work.

Current Decrease Time

With the current reduction time you can control the time of change from the main (peak) welding current to the crater weld current. It has an adjustment range of 0.1 to 10-15 seconds. During this time, the current will decrease smoothly to prevent a crater from forming at the end of the weld.

Crater Welding Current

A parameter that allows you to set the current to complete the welding process. The range is from 5-15 Amps to the maximum welding current of the machine. Allows welding to be completed without cratering.

In the 2T torch mode, the current drops and crater welding starts when the button is released, in the 4T mode the button must be pressed until the arc is extinguished.

Gas supply time after welding

Parameter at which the high-frequency oscillator is switched off and the gas valve in the machine is in the open position, thus supplying shielding gas to the torch. The adjustment range is from 0.1 to 10-15 seconds. Adjusting this parameter allows cooling of the torch and the workpiece to be welded.

Additional welding parameters

We recommend to pay attention to welding parameters that are applicable only in certain modes:

1. AC polarity balance in AC and AC Pulse mode

The polarity of the welding current has a significant effect on the arc welding process. When reverse polarity is used, the TIG welding process is characterized by the following features:

  • Reduced heat input to the workpiece and increased heat input to the electrode (therefore, when welding on reverse polarity, the electrode must be of larger diameter at the same current. Otherwise, it will overheat and quickly deteriorate.
  • The zone of melting of the base metal is wide, but shallow.
  • There is an effect of cathodic cleaning of the base metal surface, when under the action of a stream of positive ions there is a destruction of oxide and nitride films (cathodic atomization), which improves edge fusion and weld formation.

When welding in direct polarity, the following is observed:

  • Increased heat input into the workpiece and reduced into the electrode.
  • The melt zone of the base metal is narrow but deep.
How does the cyclogram affect the setup process of TIG machines?

Tip. When welding aluminum on alternating current, it is necessary to form a ball at the tip of the tungsten electrode, no more than ½ the diameter of the electrode.

To form a ball on the end of the electrode it is necessary to:

  • Set the adjustment so that the AC polarity balance is 50/50, the index is (65 15)/2=40. 40% – the balance of negative half-wave and positive half-wave is the same.
  • Set the polarity balance to the 45-50 position. On this mode the ball is formed in the given values of diameter. If you set the polarity balance higher, the positive half-wave will increase, more electrons will flow, and the bead will start to form on the tungsten.
  • After the bead is formed, we recommend returning the polarity balance to its original position.

2. AC Frequency (AC and AC Pulse mode)

This parameter affects the heat input to the metal, the stability of the arc burn, the depth of penetration and the width of the cleaning zone. The higher the AC frequency, the more stable the arc burn, the narrower the weld, the less heat input into the workpiece. It is used when welding thin sheet metal, where it is necessary to stabilize the arc and reduce heat buildup. The lower the AC frequency, the wider the weld, the larger the cleaning zone and the larger the weld penetration. It is used when welding thick metal.

3. Pulse Frequency (DC Pulse and AC Pulse mode)

This parameter affects the heat input to the metal, the stability of the arc and the depth of penetration. The higher the current pulse frequency, the more often the peak current will fall to the base current and vice versa – the base current will rise to the peak current. This ensures stable arc burning, narrow welding seam and lower heat input into the workpiece.

It is used when welding thin sheet metal, where it is necessary to stabilize the arc and reduce heat buildup. The lower the AC frequency, the less often the peak current will fall to the base current and vice versa – the base current will rise to the peak current, hence, wider weld seam, larger cleaning zone and larger weld penetration. It is used when welding thick metal.

4. RQ or pulse fill in DC Pulse and AC Pulse mode

This parameter is similar in physical meaning to the AC polarity balance. However, the pulse width does not regulate the positive or negative half-wave, but rather regulates the duration of peak and base current per pulse duration cycle.

Example: If the pulse frequency is 50 Hz, which corresponds to 20 ms, and the base and peak currents are 50 and 100 Amps respectively, if the pulse width is 50%, 10 ms the current will be 100 Amps and the remaining 10 ms will be 50 Amps, if the pulse width is 75%, 15 ms the current will be 100 Amps and 5 ms the current will be 50 Amps.

Based on the above, the higher the pulse width, the longer the duration of peak current and higher heat input into the metal, wider the weld pool. The lower the pulse width, the lower the heat input, the more stable the arc, the narrowerthe weld pool.

Remember that careful attention to the settings of welding parameters will help to avoid defects and difficulties in argon-arc welding TIG. As a recommendation, below is a table emphasizing the important points of setting the welding parameters. The table is for reference only and does not serve as a guide.

Metal thicknessWelding positionThin metal (up to 3 mm)Thick metal (from 3 mm)
LowerDCPulse frequency from 100 Hz and above.Pulse frequency from 10 to 50%.Starting current above peak current by 5-10A.Base current from 25 to 50% of peak current.Peak current up to 70-85A.
ACanalogous to DC and additionally:AC frequency from 100Hz and above.AC polarity balance above half.
DCStarting current above peak current by 10-25A.Peak current from 70-85A.
ACAnalogous to DC and additionally:AC frequency below 100Hz.AC polarity balance below half.
AngularDCPulse frequency from 150Hz and above.Pulse RMS from 30 to 50%.Start current above peak current by 5-10A, base current by 25-50% of peak current.Peak current up to 75-90A.
ACAnalogous to DC and additionally:AC frequency from 150Hz and above.AC polarity balance above half.
DCStarting current above peak current by 20-30A.Peak current from 75-95A.
ACAnalogous to DC and additionally:AC frequency below 100Hz.AC polarity balance below half or half.
Vertical (bottom-to-top welding)DCPulse frequency from 150Hz and abovePulse frequency from 10 to 50%Start current above peak current by 5-10A, base current by 25-50% of peak current.Peak current up to 75-95A.
ACAnalogous to DC and optional:AC frequency from 150Hz and above.AC polarity balance above half.
DCStarting current above peak current by 10-25A.Peak current from 70-85A. ACAnalogous to DC and additionally:AC frequency below 100Hz.AC polarity balance below half.
Horizontal (right-to-left welding)DCPulse frequency from 100Hz and above.Pulse frequency from 30 to 50%.Starting current above peak current by 5-10A, base current by 25-50% of peak current.Peak current up to 70-85A.
ACAanalogous to DC and additionally:AC frequency from 100Hz and above.AC polarity balance above half.
DCStarting current above peak current by 10-25A.Peak current from 70-85A. ACAnalogous to DC and optional:AC frequency below 100Hz.AC polarity balance below half.
CeilingDCPulse frequency from 150Hz and above.Pulse RMS from 10 to 50%.Start current above peak current by 5-10A, base current by 25-50% of peak current.Peak current up to 65-85A.
ACanalogous to DC and additionally:AC frequency from 150Hz and above.AC polarity balance above half.
DCPulse frequency from 100Hz and abovePulse frequency from 10 to 50%Starting current above peak current by 5-10A, base current by 25-50% of peak current.Peak current from 65-85A. ACAnalogous to DC and optional:AC frequency below 100Hz.AC polarity balance below half.

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