In my experience there is a disconnect between materials theory:
which discusses material properties in terms of dislocation movement, grain structures (Austenite, ferrite, HCP etc.), thermal history, etc.
and materials practice which talks in terms of standards which give you macro properties...
MJC,
Talking as an ex diesel chief when youre in the middle of the atlantic and your cooling water pumps fail and the ship looses all power a shipyard pipefitter is unlikely to be available.
Consider the following situation.
A 20" sch 120 main pipe fitted with a 16" sch 120 branch pipe using a weldolet. Should the weldolet to main pipe prep. be fully welded out?
I have seen many connections made in this way on several plants and I regularly find the weldolet to main pipe...
suraiya,
I would not select materials that do not meet the design conditions. Imagine explaining to a court of law if there was a failure that you (not the designer) made a material substitution on the basis that failure was unlikely. Challenge the process designer, if the design temperature...
If I make the assumption that your original design selected A333 with the additional costs (impact testing) that would be incurred over A106 it was because it was necessary. I would therefore be surpised if A106 would meet the design intent. If for some reason A106 is an acceptable substitute...
You might like to consider PTFE lined carbon steel pipe. It gives you the benefit of the excellent resistance to the dilute acid you get from plastic without the pipe support complications you get from all plastic pipe. The only down side is the number of flanges required as the lining lengths...
My understanding of hydrogen embrittlement (hydrogen blisters / cracking etc.) is that atomic hydrogen (H) can be intoduced by say, wet electodes in welding activities or hydrogen process steams, etc. Atomic hydrogen can diffuse easily being a small atom (the smallest) however when an atom of...