Sparking from Thermally Sprayed Aluminium Flanges.
Sparking from Thermally Sprayed Aluminium Flanges.
(OP)
Has anyone heard of the following occurance: Burning embers dropping from bolts upon on breaking of flanges.
Rough details are as follows.
Vessel side flange coated with thermally sprayed Aluminium
Pipe flange uncoated carbon steel.
Molycote 1000 grease
Embers smelling of 'fireworks' were observed falling from the nuts released from the thermally sprayed aluminium flange face.





RE: Sparking from Thermally Sprayed Aluminium Flanges.
http://www.welding-advisers.com/
RE: Sparking from Thermally Sprayed Aluminium Flanges.
We had a fire one time during a shutdown while the process people were cleaning up when an a standby operator near a drainage ditch was idly striking an Al painted steam trap with his nonsparking cheater. He lost the hair on his leg.
I was made aware of this problem in the early 50's while working for a valve company and when I went to work for a chemical company it took several demonstrations to educate management on the hazards of assuming because something called non-sparking it was. It all depends on what you are striking.
RE: Sparking from Thermally Sprayed Aluminium Flanges.
= = = = = = = = = = = = = = = = = = = =
Corrosion, every where, all the time.
Manage it or it will manage you.
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: Sparking from Thermally Sprayed Aluminium Flanges.
RE: Sparking from Thermally Sprayed Aluminium Flanges.
Thankyou for your replies. A thermite reaction is considered the most likely cause - but there are some contraindications.
1. This was the first time the joint had been split since construction (3 years ago) and there was little or no visible evidence of rust.
2. Thermite reactions, as my understanding has it, are difficult to start.
3. This reaction has not before been observed during the breaking of flanges, as far as we are aware.
4. Sparks were observed droping from every nut on this joint. (They droped from the space between the nut and the AL sprayed flange face - not from the torquing tool).
We are awaiting lab test results for samples of grease taken from the joint.
RE: Sparking from Thermally Sprayed Aluminium Flanges.
RE: Sparking from Thermally Sprayed Aluminium Flanges.
RE: Sparking from Thermally Sprayed Aluminium Flanges.
RE: Sparking from Thermally Sprayed Aluminium Flanges.