As per PV code ASME SEC VIII Div 1,impact test is not mandatory for PV
materials for P 1 and Gr1 &2 materials upto thk of 1" for majority of
materials.However for high Pressure Natural Gas applications say 100
Bar design pressure,it is asked to do impact testing at -20 deg C for
materials like A333GR6/A350LF2CL1 materials.Inspite of having
satisfactory values at testing temperature of -45/-46 deg C,testing at
-20 deg C is insisted.Can anyone explain logic behind this?
Further,it may please be noted that as per:
UCS 66(c)-no impact testing is required for B16.5 flanges of ferritic
steel when used at MDMT not colder than -29deg C and;
UCS 66(d)-pipe size 4" and below(P NO 1),impact test exemption is
there as a function of Yield Stress for temp -104 Deg C and warmer
e.g. 20 ksi to 30 ksi-6.0mm thk.Which implies that for 6.0 mm thk pipe
of 4"NB and below,no impact test is mandatory for tempr upto -104 deg
C.
However for Natural Gas applications,for material like A106GR B/A105
materials,impact test at 0 deg C is insisted for sizes 2"NB and above.
Here again,can A106GR B/A105 materials be safely used without impact
testing upto -29 deg C?
Regards
Aarpee
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