Summary from Hobart on improving Low Hy in GMAW/FCAW

By ssbn727 (*****)

Date 03-17-2014 08:40

Here's a project summary from Hobart's Tubular Wire Division research developments of adding an additive to the shielding gas to reduce the amount of weld metal diffusible Hydrogen... This is achieved by adding fluorine gas, in the form of carbon tetrafluoride (CF4) to the shielding gas for gas-shielded welding processes (FCAW, GMAW, MCAW)...

For example; Rutile-type FCAW electrodes typically contain a limited amount of solid fluorides in the core; i.e. , an amount that will provide an acceptable balance of mechanical properties, weld metal hydrogen and improved operability...

As a consequence, there are no flux-cored electrodes currently on the market which offer superior mechanical properties, very low diffusible hydrogen (consistently less than 4 ml/100 gm of weld metal) and excellent operability... There's more in this .pdf:

http://www.nsrp.org/6-Presentations/Weld/050812_Hobart_Tubular_Wire_Division_Project_Summary.pdf

An interesting summary indeed!

Respectfully,
Henry

By PlasmaHead2 (***)

Date 03-20-2014 00:01

Hello Henry, hope your doing well
Thank you for posting all of the reading material!

I REALLY hope this is for an automated application and that the operator is FAR away from the arc... :eek:

I can see how it would work with how reactive fluorine is, but in it working to remove hydrogen it would be forming hydrofluoric acid... :eek:

Something about being able to kill you by leaching the calcium out of your blood stream and shutting down your nervous system makes me shy of fluorine and its active forms...
Thank you again for sharing!
Clif

By js55

Date 03-20-2014 12:38

My question would be similar to plasmas. What would keep the arc from forming hydrogen fluoride that then mixed with moisture in the lungs would form hydrofluoric acid in the lungs, or for that matter in the gas itself, which may be as dangerous as hex chrome?
The presentation explained the welding aspects but essentially nothing on the safety of the chemical byproducts.
I'm no chemist to be sure, but its worth considering.