Fillet welds in titanium? UNF-19 2

[mengnr]

I'm looking for some guidance on UNF-19 (a), which forbids fillet welds in shells or heads of titanium vessels. Does anyone know the reason for this? We're having to implement some awkward workarounds, and without knowing the reason for avoiding fillet welds, I'm not even sure if our workarounds are ok. Thanks.

 

[SnTMan]

Well, I don't know beans about welding Ti (or anything for that matter) but I'm curious. If not full-penetration butt joints, what are you proposing for these Cat A & B joints? Lap joints? Corner joints?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[weldstan]

For A and B Category welds, proper shielding of the backside of the fillet welds is difficult and effective volumetric examination is impossible. Therefore weld integrity is impossible to define.

 

[mengnr]

Weldstan, thank you, that is interesting.

SnTMan, we're updating an old design to be BPVC compliant. It currently has lap joints with fillet welds to allow adjustability.

 

[matschka]

Take precautions when working with titanium. Make sure you read the MSDS
Also check out the following about actual titanium accidents.

http://www.practicalmachinest.com

Once ignited it cannot be extinguished. When some of our Nuclear Plants were cancelled, we had some Ht.Exchangers laying in the lay down yard that had Ti tubes that we could not get rid of. The client sold them for scrap. The junk yard scrap boys started to cut them up and "bingo'. A huge fire that could not be extinguished..