Volume of Material Required to Avoid Burn Through (Welding)

[jmarkus]

Hi,

Is there a formula or rule of thumb that I can use for MIG welding to determing the minimum amount of material required to weld, to avoid burn through?

For example, I want to weld a T-joint. The material thickness is 2mm and the height of the tab to be welded to the base is 6mm. The weld has a 3mm throat and is 10mm long. Will it burn through? What height do I need to have to avoid burn through?

| } 6mm tall
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Thanks,
Jeff

 

[moseley]

jm,
The problem is not with the height of the tab, it is a question of heat input. Welder technique is essential with this thickness of material. Adjust the heat input to a lower amperage and you should get the results that you are looking for. Hope this helps

 

[jmarkus]

Moseley,

My problem is that I am designing for robotic welding of an assembly and I am being told by the process engineer that I need a certain height. I was thinking that if I need to change the thickness then I could have a shorter height (if I maintain the same volume - 'heat sink'- for a given heat input). There are many other welds in the area and they probably want to use the same input for all of the welds so they don't lose time in the process by stepping down.

Thanks,
Jeff

 

[welding1]

You need a predominantly inert shielding gas, such as argon + 5% CO2. You need a 0.8mm wire and short circuit arc transfer. You should not burn through but you may create a huge gooseberry on the other side if you don’t use the correct technique.

Beware of lack of fusion with this welding process; do a test piece and put it in a vice and destroy it with a hammer.

John

http://www.gowelding.com

 

Jeff, there is no free lunch! Regardless of any rules of thumb which you get, you will ultimately need to perform test welds or waste a number of production parts to get the desired welds. Consult with your welding engineer and perform some test welds using the range of welding variables in your detail welding procedure. Bob