Impact tested or normalized

[jtseng123]

Dear all,

Say SA-516-70, looking at Fig UCS-66 and it falls between curve B and D. Shall I ask impact tested or normalized material ?
Kind of getting rusty now for simple question. Your help please. I remember some says if the thickness is above certain value, ask normalized instead of impact tested.

 

[metengr]

Order the material to SA-516 Grade 70 material specification, and specify a normalization heat treatment. Impact testing is a method for either an owner's requirement or code requirement for use of the material. Please review the SA-516 material specification.

 

[jamesl]

Order normalized will give you Curve D.

 

[jtseng123]

But I believe if vendor can do impact test and pass the energy value, normalization is not required and will save cost. So, is there any problem to specify " SA-516-70 impact tested " in lieu of "SA-516-70N" ? I did see it was done this way by some people.

 

[jamesl]

If you don't care if the plates are normalized, it is better to specify SA-516 only. Vendor can choose to buy as rolled plates with impact test or normalized plates to get away with impact test, whichever is more convenient and economical.

 

[jtseng123]

jamesl,
Sounds good to me. Thanks.

 

[metengr]

If you read SA 516, like I mentioned earlier, as-rolled plates will be provided for 1.5" and under with no impact test. For plates over 1.5" you have no choice, the plates shall be furnished normalized.

Impact test? This is a supplemental requirement, S.5, that YOU need to provide to the supplier. What are you going to accept? Look at 5.3 below

5.3 When notch-toughness tests are required on plates
11⁄2 in. [40 mm] and under in thickness, the plates shall be
normalized unless otherwise specified by the purchaser.

 

[jtseng123]

metengr,
that means I have to specify normalized material regardless, even I only need 3/4" thick plate. If that is the case, many of our past practices of specifing "SA-516-70 impact tested" were incorrect.

 

[stanweld]

For 3/4" plate, it will be up to the manufacturer to normalize the plate in order to meet the impact requirements specified in your purchase order when you also specify as-rolled product. Otherwise, whenever you ordered "impact tested", your plate was normalized.

 

[curtis2004]

Dear Friends,

Correct me if I'm wrong.UCS-66 determines when impact test is required for CS vessels based on materials, thickness, and MDMT. If material thickness at certain MDMT falls below a curve, then for materials listed for this curve impact testing is not mandatory (or required).
If it falls above curve, then you need either to have this material impact tested at MDMT temperature, or consider another material which may be suitable for service without impact testing requirement.
Now, how about PWHT plays into all this? If material is normalized, does it also need to be post weld heat treated in order to qualify for impact testing exemption?
Does welding procedures has to be pre-qualified for certain temperature MDMT?
By the way, what is more economical: heat treatment or impact testing?

Thanks in advance for clarification.
Curtis

 

[stanweld]

Curtis2004,
Impact testing may be invoked by the end user, his Engineer, ASME B31.3, ASME VIII or other national/international standards. Under ASME VIII, the SA-516 plate heat treatment may well require additional post weld heat treatments. A new WPS may not be required to be qualified on the production materials; however, production plate weld impact testing may be required per UG-84.

 

[SnTMan]

curtis2004, UCS-68 allows a 30 deg F reduction if PWHT is performed when not otherwise required by Code. The pervious state of the material, i.e. normalized or not, has no bearing.

Code does not state that normalized materails shall be PWHT, that is governed by UCS-56 and various other sections related to service, etc.

Impact qualified weld procedures are needed below certain temperatures per UCS-67.

Regards,

Mike

 

[curtis2004]

Hi all,

Let's review the following example:

1. Pressure vessel built to ASME BPVC Section VIII, Div.1
2. Design pressure: 150 psig; MDMT -55F;
3. Material used: Shell - SA-516 Gr.70 Normalized 3/8" thick plate; Heads 2:1 Elliptical SA-516 Gr.70 Normalized 3/8" thick plate;
4. Neither PWHT nor Impact testing is specified by customer.

If we assume that this vessel should only comply to Section VIII, Div.1:
Q1. Is this material impact test exempt or not? Why?
Q2. Is PWHT required? Why?
Q3. Vendor has welding procedures qualified for -40F. Can he use it without re-qualification or not?

Thank you all,
Curtis

 

[stanweld]

Since you have not indicated any exemptions per UCS-66 based on the design.
Q1. The material is exempt from impact testing per Fig UCS-66 and Note 4 thereof.
Q2. PWHT is not required per UCS-56 unless in Lethal Service per U-2.
Q3. WPS must be additionally impact test qualified at -55F on P No.1 Group 2 material unless the filler metal manufacturer has classified it by impact testing per the applicable SFA specification at a temperature not warmer than the MDMT per UCS-67 (a)(3).

 

[SnTMan]

curtis2004,

Q1, exempt, Curve D material
Q2, no, not required by UCS-56, unless required by service (UW-2), or by other Code rules.
Q3, Unqualified procedures may be used in some cases, see UCS-67(a)(3). In this case the vendor procedure may be used as is. Otherwise, weld procedure needs to be qualified for -55 F, unless 15 F reduction can be obtained by UCS-66.

Regards,

Mike

 

[curtis2004]

Great!
We've got consensus on two out of three questions.
On Q3 both answers seems logical. However, temperature reduction obtained from UCS-66, does it take into consideration only material of vessel, or filler material? I think in order to qualify for temperature reduction filler material and WPS also should qualify. This is my subjective opinion. What are your thoughts, gentlemen?

Thank you,
Curtis

 

[SnTMan]

Not necessarily, the consumable(s) only may be qualified by their manufacturer, see UCS-67(a)(3).

Regards,

Mike