permissible number of times of flux reusing

[leedrong]

When welding of mild and high tensile carbon steel welding using AWS F76-EH14 rod and flux ( Submerge arc welding Process ) , What is the permissible number of times of flux reusing for welding quality control standpoint ?

We had an experiance that when we use mixed flux ,half new flux with half used flux which reused seberal times , we can see few spots on surface of bead and rarely observed cracks in deposited metal of thick plate welding .

 

[metengr]

leedrong;
First question - are you referring to "used flux" as slag OR flux that was not converted to slag during welding, but still looks like flux?

Second question - Do you have a closed loop recycling program for your SAW slag? What do you do with your slag from SAW?

Flux that has NOT reacted during the welding process (forming slag) can be picked up, and reused. From what I have read in AWS 5.17, there is no requirement limiting the number of times flux can be recycled with new (virgin) flux. However, it is important to note that contaminants like moisture, oil or debris can be picked up from the unused flux, thus contributing to your problem. I would not mix the unused flux with new flux. Unused flux could be captured and blended with crushed slag, and tested for electrode-flux reclassification in accordance with AWS guidelines.


The 1996 June edition of the AWS Welding Journal contains an excellent article on "Recycling of SAW Slag Proves Reliable and Repeatable".