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Reducing the use of Helium
in GMAW Applications
on Nickel-Based Alloys
Improve Productivity & Quality; Reduce Total Cost
MATHESON QuickView
Application Review and Summary

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Helium Supply Update
• Helium is a non-renewable resource
• Helium supply is subject to variability
– Helium prices fluctuate … and the future is unpredictable
• For welding applications, alternatives to helium exist
– Many of the alternatives offer advantages
Now is the time to consider shielding gas
alternatives that use less - or zero - helium.

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Why use Helium?
• Helium creates a high energy arc
– High ionization potential (24.5874 eV)
– Produces hotter arc (at higher voltages)
• Produces a shallower, wider bead profile
– Effect is proportional to Helium concentration
• High heat can be advantageous on thicker sections
• Helium can be useful on aluminum, magnesium, copper alloys
• Helium when blended with Argon, CO2, and other gases, creates a
mixture with blended characteristics
Frequently Specified Application:
Mixtures rich in Helium – typically 90% - for Stainless Steel

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Helium’s Disadvantages
• Helium’s high ionization potential leads to:
– Less stable arc – can lead to inconsistent results Disadvantages
are proportional
– Hotter arc – can lead to distortion & warping to Helium
concentration
• Helium can lead to penetration issues
• Helium can increase spatter
• Helium is a light atom and a less effective shield
– Helium flow rate per unit of deposited metal is higher than other gases
• Helium is subject to supply and price variability
– The cost of Helium must be considered in high production applications
Using more He
is not the only choice;
and is often not the
best choice.

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GOAL: Reduce or Eliminate Helium Use
• Alternatives to Helium exist
• Helium use can be reduced Consider mixtures
or eliminated optimized for the
• With excellent results: process and
– Better weld penetration application.
– Significant reduction in porosity
– Increased travel speed
– Improved arc stability; less spatter and smoke
– Improved puddle and flow control (smaller droplet)
– Reduced Heat Affected Zone (HAZ)
– Less heat-related damage to base material
– Reduced burn-through on thin materials
– More flexibility to use other processes (spray and pulsed spray, in addition to short
circuit)

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GMAW on Nickel-Based Alloys

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Nickel-Based Alloys GMAW
• Outdated: 90%He / 7.5%Ar / 2.5%CO2
– Expensive for GMAW of stainless steel and other alloys due
to high concentration of Helium
– Narrow voltage range (18V-22V)
– Limited to Short Circuit Transfer
– High heat (due to high ionization potential of He) is detrimental to
mechanical properties of base material
– Distortion, poor color match, warpage, suck-back, poor
productivity

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Nickel-Based Alloys GMAW
• Different conventional setups for stainless steels
– For Short Circuit: 90%He / 7.5%Ar / 2.5%CO2
– For Normal or Pulsed Spray: 98%Ar / 2%O2
• Well known fact:
– Neither of the above shielding gas mixtures is optimized for
both short circuit and spray
• For Stainless Steels, you must have two setups with traditional gas
mixture compositions – one for short circuit and one for spray

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Nickel-Based Alloys GMAW
• 90%He / 7.5%Ar / 2.5%CO2
– Works well for Short Circuit
• Here’s why you can’t use it for Spray Arc:
90%He / 7.5%Ar / 2.5%CO2
If used for Spray Arc:
• Very unstable arc
• Large droplet formation
• Explosive transfer

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Nickel-Based Alloys GMAW
• MATHESON Select® HC-725 (and HC-332)
– Use up to 90% less Helium; uses more Argon instead
– Expanded Voltage Range (14.5V-38V)
• Use of lower voltages results in less heat input
– Lower operating temperature Stainless Steel
• Inconel®
Reduced heat on lighter materials
Hastelloy®
• Reduced burn through, suck-back Monel®
• Reduced HAZ
• Reduced hexavalent chromium emission
– Higher productivity and lower total welding cost
– One mix ideal for short circuit, spray, and pulsed spray

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Nickel-Based Alloys GMAW
• MATHESON Select® HC-725
– One mix ideal for short circuit, spray, and pulsed spray
– One setup is appropriate for all processes
• Here’s a look at
MATHESON Select® HC-725 for Spray Arc:
HC-725 with Spray Arc:
• Stable plasma
• Small droplet formation
• Smooth transfer

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Nickel-Based Alloys GMAW
• In some applications:
– Users may be able to switch from Short Circuit to Spray Arc
– Spray Arc is faster – reducing not only time, but cost
• Some studies show total cost cut in half!
– Users who use MATHESON Select® HC-725 Shielding Gas
• Can use Spray or Pulsed Spray for higher speed, cost
savings, and better results
• Can switch back to Short Circuit as needed

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In Review …
• Forward thinking leads to better solutions
Thank you
• Use of less Helium can: for your
– Produce better results time!
– Improve cost per weld
– Enable the use of ONE SETUP for all applications on SS
• Easily applied in GMAW and GTAW on Nickel-Based alloys
• We are here to support you
• Learn more: contact your MATHESON rep or visit one of our stores
• Find us fast at: www.MathesonGas.com/contactus.aspx