President
- FMA
- The Fabricator
- FABTECH
- Canadian Metalworking
Categories
- Additive Manufacturing
- Aluminum Welding
- Arc Welding
- Assembly and Joining
- Automation and Robotics
- Bending and Forming
- Consumables
- Cutting and Weld Prep
- Electric Vehicles
- En Español
- Finishing
- Hydroforming
- Laser Cutting
- Laser Welding
- Machining
- Manufacturing Software
- Materials Handling
- Metals/Materials
- Oxyfuel Cutting
- Plasma Cutting
- Power Tools
- Punching and Other Holemaking
- Roll Forming
- Safety
- Sawing
- Shearing
- Shop Management
- Testing and Measuring
- Tube and Pipe Fabrication
- Tube and Pipe Production
- Waterjet Cutting
Industry Directory
Webcasts
Podcasts
FAB 40
Advertise
Subscribe
Account Login
Search
Aluminum Workshop: An introduction to pulsed MIG power supplies
- By Frank Armao
- December 19, 2014
- Article
- Aluminum Welding
Q: What’s the story behind pulsed gas metal arc welding (GMAW) aluminum? Some think it’s great, but others say it’s just a way for equipment makers to sell expensive power supplies.
A: GMAW transfers metal in three ways. At low currents, you get short-circuit transfer, in which the molten droplet on the GMAW wire makes contact with the work. This works well for steel wires, but not for aluminum because the weld isn’t hot enough to overcome aluminum’s high thermal conductivity, and lack-of fusion defects often result.
If you raise the current above the transition current, you get spray transfer, in which magnetic forces transfer tiny droplets across the arc. Spatter levels are low, the weld is hot enough to avoid lack-of-fusion defects, and you can weld out of position. Spray transfer is recommended for aluminum GMAW.So why not just spray-transfer aluminum? Why consider pulsed spray? Because while spray transfer isn’t a problem for thick aluminum, it is for thinner aluminum.
The transition current for 3/64-in. aluminum wire is approximately 135 amps. This is the minimum current you can use to spray transfer-weld aluminum with this wire. While that’s fine for materials thicker than 5/32 in., what about thinner materials?
Pulsed spray GMAW power supplies pulse the current between a peak current above the transition current and a background current significantly below the transition current. Wire droplets are transferred across the arc in spray transfer when the arc is at peak current, but no droplet transfer takes place when the arc is at background current. What’s the net effect? You can get spray transfer at average currents well below the transition current. That makes it easier to weld thin aluminum, weld out of position, and train new welders to GMAW aluminum. However, pulsing power supplies are more complex, so they cost more.
Pulsed GMAW power supplies aren’t a panacea. Use them where it makes sense—for thin aluminum and out-of-position welding.
About the Author
Frank Armao
Aluminum Consulting Inc.
440-479-0239
About the Publication
Related Companies
subscribe now
The Welder, formerly known as Practical Welding Today, is a showcase of the real people who make the products we use and work with every day. This magazine has served the welding community in North America well for more than 20 years.
start your free subscription- Stay connected from anywhere
Easily access valuable industry resources now with full access to the digital edition of The Fabricator.
Easily access valuable industry resources now with full access to the digital edition of The Welder.
Easily access valuable industry resources now with full access to the digital edition of The Tube and Pipe Journal.
Easily access valuable industry resources now with full access to the digital edition of The Fabricator en Español.
- Podcasting
- Podcast:
- The Fabricator Podcast
- Published:
- 03/26/2024
- Running Time:
- 67:51
This week on The Fabricator Podcast, Jason Becker, host of the Arc Junkies Podcast and owner of Underground...
- Trending Articles
A welding instructor’s career path to working with metal
The importance of welding procedure specification (WPS)
Urban Steel Rockstars festival will highlight welding and steel industry
Keys to adopting welding automation successfully
Sensors use AI to assist robotic weld grinding
- Industry Events
Coil Processing Workshop & Tours
- April 2 - 3, 2024
- Corpus Christi, TX
GOLF4MFG South
- April 15, 2024
- Charlotte, NC
16th Annual Safety Conference
- April 30 - May 1, 2024
- Elgin,
Pipe and Tube Conference
- May 21 - 22, 2024
- Omaha, NE
World-Class Roll Forming Workshop
- June 5 - 6, 2024
- Louisville, KY