Argon and mig welding

[lerner]

Hi all

i am using pure argon on my mig (you must think im mad)well i do tig welding to, and i have only 2 bottels so if one runs out i can use the other ,what i notised was i can weld at 2.5l/m on my tig
(whith a gas lens) and on my mig the same 2.5l/m, is this the argon or is my regulater bugerd in sa argon and a co2 mix costs the same

 

[shenion]

My first bottle of gas was argon for my MIG. It worked well but the welds were tall.

2.5 l/min is real low. About 5 l/min is as low I have seen on MIG. Have seen 3 l/min recommended by Clarke on disposable bottles.

Lower will work, most of the time. But any stray fan/breeze or even as the metal heats up and air starts rising creating currents can cause porosity problems at low rates.

 

[backpurge]

I wouldn't use Argon for MIG welding anything out of steel that will be under any stress, as shenion says the flow rates are bit low particularly for MIG, any drafts could cause porosity and with flows that low it is possible to get an ingress of N2 into the weldmetal

 

[TechnicAl]

As Backpurge say Nitrogen will embrittle the steel well before it creates a porous weld.

 

[lerner]

thanks for helping i shall take some picturs and post them so jou can see and tell me what you think i have a nother one is it more expensive to braze m/s to castiron or to weld with spesial rod thinking off time and gas