Hardness of U tube
Hardness of U tube
(OP)
We Require A179 U Tube set, where we have specified that Hardness test to be done on the shortest U Bends after Stress Relieving. The Hardness Values obtained are 78 & 74 HRB respectively, noting that the Max Hardness value as per ASTM A179 tubes are 72HRB (nothing Mentioned about U bends)
Can anyone advice on the above and specify any supporting standard/document for reference. Can we accept the obtained hardness of 78 & 74 HRB
Can anyone advice on the above and specify any supporting standard/document for reference. Can we accept the obtained hardness of 78 & 74 HRB





RE: Hardness of U tube
What is the actual hardness outside of the stress relieved area?
A couple of points does not bother me, but you need to decide why it might matter to you.
Did you look at microstructures?
And how accurate is the hardness, taking RB on a tube can have significant errors.
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P.E. Metallurgy, Plymouth Tube
RE: Hardness of U tube
RE: Hardness of U tube
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Hardness of U tube
Was this for a u-bend or weld region? Typically, for u-bend the stress relief is optimized to provide a specified maximum hardness, which may be lower than the hardness from PWHT.
RE: Hardness of U tube
Client supplies a spec requiring SR of the U-bend, but without specifying hardness requirement.
The value (200 Brinnel) was selected from an additional spec relating to the specific service. Said spec seems to require no hardness testing for base metals.
Client to review...
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Hardness of U tube
RE: Hardness of U tube
RE: Hardness of U tube