- This topic has 4 replies, 3 voices, and was last updated 7 years, 2 months ago by
.
-
Posts
-
I have come across this exemption before. Power station boiler tubes & piping – can’t remember exact thicknesses, but around 60mm OD x 5 – 6mm thick; Material 2.25%Cr, 1Mo.
P22 material has a maximum allowable carbon content of 0.15% IIRC.
A1 – Item C refers to parent metal composition. PWHT for carbon steel is not required below thicknesses of 32mm.
A2 – Yes, correct. Go off the thickness of the thinner material.
My point is the combination of the two dissimiar materials one of A106 Gr.B having 0.25% C forms the basis of the joint, there for does that joint still conform to the requriments of the exemption, i dont beleive so.
a) equal to or less than 12mm
b) equal to or less than 127 OD
c) less than 0.15 C content
Its all a matter of interpretation but im definitly in favour of majority rules, so lets hear some more opinions.
I might be setting myself up for dissapointment but here goes.
Chris,
If the carbon steel is less than 12mm, it automatically does not require heat treatment.
Carbon steel only requires heat treatment at 32mm and above.
- You must be logged in to reply to this topic.