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2-stroke and 4-stroke mode in welding

  • Updated

Many welding machines offer the option to choose between 2-stroke and 4-stroke operation.
These operating modes determine how the welding process is started and ended via the torch trigger.
Both in MIG/MAG welding and in TIG welding, 2-stroke and 4-stroke are common and proven functions which offer different advantages depending on the application.

 

What do 2-stroke and 4-stroke generally mean in welding?

The terms 2-stroke (2T) and 4-stroke (4T) describe how many actions are required on the torch trigger to start and end the welding process. The actual welding process (arc, gas, wire) remains the same – only the operating logic differs.

 

mode Symbol Description
2-stroke (2T)
Particularly suitable for short welds or in automated operation. Welding is carried out by holding down the torch trigger (stroke 1). Welding stops by releasing the torch trigger (stroke 2).
4-stroke (4T)
Particularly suitable for longer welds. Welding is carried out by pressing (stroke 1) and releasing (stroke 2) the torch button. Welding is stopped by pressing the torch button again (stroke 3) and releasing it (stroke 4).

 

 

2-stroke mode – How it works

In 2-stroke mode, the welding process only runs while the torch trigger is pressed.

Sequence:

  1. Press torch trigger → gas, wire and arc start

  2. Release torch trigger → welding process ends immediately

 

Advantages of 2-stroke mode

  • Very simple, direct operation

  • Good control for short welds

  • Ideal for tack welding

  • Particularly clear for beginners

Typical areas of application

  • Short welds

  • Spot and tack welding

  • Work with frequent start-stop

  • Thin sheet metal work

 

4-stroke mode – How it works

In 4-stroke mode, the welding process is “switched on” without having to keep the trigger pressed at all times.

Sequence:

  1. Press and release torch trigger → welding process starts

  2. Welding without holding down the trigger

  3. Press and release torch trigger again → welding process ends

 

Advantages of 4-stroke mode

  • Significantly less hand fatigue

  • Smoother working for long welds

  • More uniform welding process

  • Better handling in demanding positions

Typical areas of application

  • Long welds

  • Series work

  • Overhead or constrained positions

  • Precise TIG welding

 

2-stroke and 4-stroke in MIG/MAG and TIG

Both operating modes are common in MIG/MAG and TIG welding machines. Especially in TIG welding, the 4-stroke mode is often used because it relieves the hand and allows for smoother guidance of the weld.

 

Setting 2-stroke and 4-stroke mode on RED welding machines

The MIG/MAG welding machines as well as the TIG welding machines from RED by Lorch can be operated in both 2-stroke and 4-stroke mode. 

On RED by Lorch welding power sources, there is a selector button on the control panel to select the desired mode. The active operating mode is displayed either with symbols (see table above) or with 2T (2-stroke) or 4T (4-stroke). 
You can find further details on selection for your RED by Lorch device in the operating manual. 

 

Notes:
Which other operating modes your welding machine supports and how to select them can be found in the device-specific articles or in the user manual.

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