SA-414 Grade G UCS-66 Curve
SA-414 Grade G UCS-66 Curve
(OP)
Pressure Vessel built to Sect. VIII- Div. 1
There is some disagreement over what curve SA-414 G should be listed on in UCS-66(b). Our calc software automatically selects curve A. The SA-414 G material is in the shape die-formed heads. Impact test is not required for the construction of the vessel.
Can someone shed some light on this?
There is some disagreement over what curve SA-414 G should be listed on in UCS-66(b). Our calc software automatically selects curve A. The SA-414 G material is in the shape die-formed heads. Impact test is not required for the construction of the vessel.
Can someone shed some light on this?





RE: SA-414 Grade G UCS-66 Curve
Regards,
Mike
RE: SA-414 Grade G UCS-66 Curve
I appreciate the reply.
There are a couple of arguments that have been made:
1) Since the heads are die-formed they should be permitted to go to curve B since UG-11(b) talks about die formed heads.
2) Since SA-414 A is listed as a curve B material and SA-414 G has better strength, then grade G should be allowed on curve B.
I more lean towards accepting the first argument. I don't believe the second argument has much weight since their isn't literature in code that backs it up.
What is your thought process to help you arrive with curve A? Any feedback is very helpful.
Thanks.
RE: SA-414 Grade G UCS-66 Curve
Aren't you exempt by UG-20(f)?
RE: SA-414 Grade G UCS-66 Curve
RE: SA-414 Grade G UCS-66 Curve
If the head is supplied under and meets UG-11(b), then I'd agree it can be classified as Curve B, otherwise not. Notice this Note UG-66 (2)(d) can place material on a higher (lower letter) curve as well as a lower one.
With Don56, I also disagree w/ your point 2). Don't think you can say that.
Exempt by UG-20 or from UG-20? Not familiar w/ 1518-5
Regards,
Mike
RE: SA-414 Grade G UCS-66 Curve
The heads meet requirements UCS-79(d), UG-77(c), UG-79, & UG-81. The heads are not heat treated.
Head thickness: .250"
Max Working Pressure: 495 psi
Max Metal Temp: 650° F
MDMT: -20° F
RE: SA-414 Grade G UCS-66 Curve
Regards,
Mike