Posted by bernard towers on 28/09/2022 14:55:54:
I said propylene which I think you will find is the replacement for dissolved acetylene.
Propylene isn't a straight replacement for acetylene, it still causes hydrogen embrittlement when fusion welding steel and cast iron, because of the increased proportion of Hydrogen in the fuel.
I mentioned propane because I have already substituted acetylene wherever it's not necessary, and propylene would just be a more expensive propane alternative.
As you can see below, the proportion of H2O in the combustion gasses of Propylene is much higher than Acetylene, and only slightly less than Propane.
C2H2 + 3 O2 → H2O + 2 CO2. (Acetylene)
Vs
C3H6 + 6 O2 → 3 H2O + 3 CO2 (Propylene)
Vs
C3H8 + 7 O2 → 4H2O + 3 CO2 (Propane)
It is specifically the fact that CO2 rather than H2O predominates in the combustion products which allows acetylene to be used for self-shielded fusion welding of steel and iron.
Edited By Jelly on 28/09/2022 15:39:02