Benefits of Pulse Welding

Earlier this week a manufacturer ask if there were any true benefits of using pulse over CV in the MIG process.  The short answer is “absolutely.” But before we can answer we need to ask: “what is the application?”  To really appreciate the benefits of pulsed GMAW compared to traditional CV (short arc or globular) it is helpful to have fundamental knowledge on the different modes of metal transfer.  In the next few days we will post an in-depth look at the different modes.  For now, we’ll focus on listing the advantages and limitation of the pulse process.

Pulse welding is simply alternating between a peak (high) and a background (low) current. Metal is transferred through the arc during the peak current.   It is also important to mention the difference between pulse and spray pulse.  Many people use these terms interchangeably and it can create some confusion.  When we say “pulse” we assume “spray pulse”.  Spray transfer is achieved when the arc reaches an energy level at which the molten droplets are transferred through the arc. Below this energy level metal is transferred by creating a short with the base material and then separated by a blast of amperage.  Pulsing is a feature of the power source. You can be pulsing (alternating between high and low current) but if you are not above the transition current you would not be in a true spray transfer.  You would get some benefits of pulse welding, but not all.   The advantages and limitations shown below assume you are spray pulse welding.  The other variable in achieving spray transfer is the shielding gas.  You need to have at least 83% Argon.  Common blends suitable for pulse welding are: 90%Argon/10% CO2

Advantages of Pulse Welding

–          Reduction in overall heat input (decreases distortion, decreases the heat affected zone)

–          Reduction in spatter (reduces rework and secondary operations)

–          Higher deposition rates out-of-position (product of rapid cooling of the puddle during background current of the cycle)

–          More resistant to lack of fusion than other modes of transfer (most people assume pulse welding reduces penetration)

–          Can reduce fume levels generated by the arc compared to other modes of transfer

Limitations of Pulse Welding

–          Equipment is typically more expensive than conventional step-down transformer power sources

–          Gas blends required are more expensive than the commonly used 100% CO2 or 75%Argon/25% CO2 gas.

–          Higher arc energy produces higher levels of radiated heat and a brighter arc, this requires a darker shade for the welding lens and more protection for the welder (usually gloves with heat shield)

Do you have experience with pulse welding?  What are your thoughts?

 

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7 thoughts on “Benefits of Pulse Welding

  1. I worked as an inspector at a fabricator that used Pulsed Arc for fabrication of 317LMN scrubbers and ductwork. One thing I must say is that just like short circuit, improper settings can result in lack of fusion. Though it is pulsing and at some point hitting the transition current, the welders can easily adjust “TRIM” to a point where the arc is long, or WFS where the overall heat input is too low.

    I think we all could use some specific training on what we are doing sometimes. Often time MFg’s get some equipment on suggestions from someone but really never study the process. I don’t know all I should know about it.

    • You are correct. As welding technology advances there are more and more variables we can control. New machines have the ability to lock out welding procedures (amps, volts, CV, pulse, etc) but unless you are welding with a robot you will always have the human variable.
      What we have found in our experience is that training welders is essential, regardless of how long they have been welding.

  2. I am wanting to learn more about welding. I like how you mention pulse welding can reduce fume levels. I would imagine this would be beneficial to lessen the fume levels for the welders health. Thanks for the information!

    • Thanks for your comment Alise. Really enjoyed reading your company’s blog posts on stainless steel and aluminum. We sometimes get to focused on how to weld materials we forget about all the benefits it provides the end user on a finished product.

  3. I knew nothing about pulse welding by reading this article. I like how you explained that pulse welding can help to reduce fume levels. I hope that I can remember this article the next time I have to have something welded.

  4. Being able to reduce the amount of fumes produced when welding would be important if they were potentially harmful. I have no experience with this kind of thing though so I would probably just hire a welding service for anything that I might need. It would probably be cheaper that way than trying to learn how to weld then buying all the equipment that I would need.

    • Hi Kylie, you are right. If welding is not a core operation in your business hiring a contractor or welding service is probably the best thing. Welding fumes can be harmful. The degree to which they can affect welders depends on the contents of the fume (particulate) as well as the concentration. Per good practices we should always try to minimize our exposure to welding fumes, regardless of whether they are harmful or not.