Interpreation on UCS-85

[Fizza453]

Are the following interpreations not in contradiction?
Dish head (material is P.No-1 and Group No. 2) is hot formed at normallizing termperature (above the lower critical temp) and welded with shell. Complete vessel then undergoes PWHT.
I have opinion that test specimens should see only similar normallizing heat treatment to meet UCS-85, specimens need not to see normallizing plus PWHT heat treament, I am assuming here that plate was in as-rolled condition. 2nd and 3rd interpreations say also like this but 1st interpreation says that specimens should see both normallizing and PWHT treatments.
If the plate were in normallized condition then no heat treatment of test specimens is required.

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Interpretation: VIII-1-83-32
Subject: Section VIII-1, UCS-85(b)

Date Issued: October 4, 1982
File Number: BC82-240
Related Documents:

Question (1): Are material test specimens exempted from heat treatment under UCS-85(b) when the material, which is a P-No. 1, has undergone heat treatment during fabrication of the vessel above the critical temperature, followed by postweld heat treatment?

Reply (1): No. The specimens must be subjected to the same manner of heat treatment, including postweld heat treatment, as the material used in the vessel, since the heat treatment during fabrication exceeded the critical temperature.

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Interpretation: VIII-1-89-19
Subject: Section VIII, Division 1 (1986 Edition, 1987 Addenda), UCS-85
Date Issued: September 20, 1988
File Number: BC88-120
Related Documents:

Question: A vessel made from P-No. 1 Group No. 1 or 2 material is to undergo two heat treatments during fabrication, i.e., normalizing above the critical temperature and a postweld heat treatment. If the coupon representing the material undergoes only the normalizing above the critical temperature heat treatment, do the test results obtained from this coupon satisfy the requirements of UCS-85?

Reply: Yes
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Interpretation: VIII-1-83-227
Subject: Section VIII-1, UCS-85(b) and (e)
Date Issued: May 31, 1984
File Number: BC82-563
Related Documents:

Question (1): A dished head made of P-No. 1 Gr. Nos. 1 and 2 material with a thickness of less than 1¼ in. is hot pressed at a temperature of 1750°F. Are test specimens required under UCS-85 of Section VIII, Division 1, to establish the mechanical property of the material?

Reply (1): Yes.

Question (2): If the head described in Question (1) is welded to the shell and then postweld heat treated at 1150°F, are additional test specimens simulating the postweld heat treatment required?

Reply (2): No.

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Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

Fizza453;
Keep one thing in mind with interpretations. Interpretations should be viewed as directly applicable when the wording of the code has not been revised in subsequent editions of the code. In cases where the code text has not changed they can be valid. With that said, I reviewed UCS-85 as it is today and my interpretation is that in UCS-85 (b) all thermal treatments during fabrication except as exempted;
In UCS-85(f) materials conforming to P-No 1 Groups 1, 2 are exempt from UCS-85 requirements if the fabrication was limited to PWHT at temperatures below the lower transformation (subcritical).

 

[Fizza453]

So then material should see both normalization (by assuming that material is as-rolled before forming dish head) and PWHT in order to meet UCS-85(b) and UCS-85(c)because material is not exempt by UCS-85(f)in the above case?

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

For your example above where the head is hot worked within the normalization range, cooled, welded and given a PWHT, yes, test specimens exposed to the hot work/normalization treatment and PWHT are required. The reason is you have performed multiple thermal treatments on original material and therefore the mechanical properties need to be verified. If you had purchased the head as-formed with certs and all that was done was to weld to the shell material using PWHT as one thermal treatment, coupon testing would have been exempted.

 

[Fizza453]

If the plate was in normalized condition before forming then? and rest of details are the same

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

Makes no difference. If you heat above 900 deg F, this is a thermal treatment. If you had purchased the head as a completed component and all that was needed was to PWHT to the shell, this is different.