Gas Home - Gas Info - Safety Info - Safety Bulletins

What is Astec™ S5?

Astec S5 is a precisely controlled active shielding gas mixture for the high quality short circuiting (dip) transfer MAG welding of austenitic stainless steels.

The benefits of Astec S5

Astec S5 offers the following benefits over argon based shielding gases:

• Increased welding speed.
• Increased penetration.
• Improved weld appearance:
  • enhanced bead profile
  • cleaner, brighter finish
  • less spatter
• Improved productivity.
• Lower reject level.
• Improved cost effectiveness.

The technology of MAG welding with Astec S5

Astec S5 is a helium based MAG welding shielding gas mixture, specifically developed for use with the dip transfer technique on conventional MIG/MAG equipment. This combination offers an all-positional capability on austenitic stainless steels with operational characteristics and techniques in line with those used for mild steel.

Argon with 1 or 2% O2 has been the traditional shielding gas mixture for the MAG welding of austenitic stainless steels. Welds produced with argon–O2 mixtures tend to be heavily oxidised, the level of penetration is very limited and welding speed is relatively slow. This limits the applications available for the process.

Astec S5 overcomes these problems.

	Argon +2% O2 bead profile.
	Astec S5 bead profile.

In order to control oxidation during welding Astec S5 utilises CO2 to stabilise the arc. This results in a dramatic reduction in the level of surface oxidation on the weld and either negates or substantially reduces the requirements for post weld dressing. The amount of CO2 present in Astec S5 is tightly controlled to limit the transfer of carbon from the shielding gas to the weld pool.

The helium content of Astec S5 provides a higher arc voltage due to the high thermal conductivity of helium. This results in greater heat input and enables the welding speed to be increased. An improved penetration profile is obtained. The improved thermal efficiency allows a smoother welding technique to be accomplished, reducing spatter.

It is recommended that where possible a 'high silicon' type filler wire should be used with Astec S5 to increase the ease of operation of the process and enhance the appearance of the weld.

Analysis

Astec S5: 75% He, 23.5% Ar, 1.5% CO2 (EN439: M12(3)).

Parameter guide for dip transfer with Astec S5
material thickness (mm)	flow rate (1/min)	wire dia.(mm)	amps	volts
1.6 3.2 6 9	14-16 14-16 14-16 14-17	0.8 1.0 1.2 1.2	70-90 110-130 120-140 140-150	19-20 19-21 20-22 20-22
This parameter table is to be used as a guide, parameters will depend upon joint type, wire diameter, etc.

 

What is Astec S5? is available in the Portable Document Format (.pdf). To view a .pdf file, you will need a free copy of the Acrobat Reader.

What is Astec S5?

Get the Acrobat Reader