Normalized w/Accelerated Cooling & Tempering (NACT) vs Normalize & Tempered (N&T) 2

[jt1234]

Dear all,
Normally we put "N&T" as a common term and practice on vessel data sheet for low alloy material. Supplier is offering "Normalized w/Accelerated Cooling & Tempering (NACT)" heat treatment. I see it is acceptable. However, supplier's PQR is showing " N&T" material. Is it necessary to ask supplier to re-qualify PQR using NACT material ? We have different opinions in house. One yes one no.
Please help if you are familiar with this.

 

[weldstan]

Per ASME IX, no. For very thick steels, accelerated cooling from the normalizing temp is required to maintain a normalized structure. This is not quenching.

 

[sharmass]

If you consider 2023 edition of Sec VIII-1 or VIII-2, Code has changed for P1 Gr 1 and 2 materials. Heat treatment condition is no longer a variable enforced by construction Code. If the material is other than P1 Gr 1 or 2 or if you are mandated to use edition prior to 2023, NACT should be considered as quenched and tempered condition. Please refer to Code interpretation II-A-10-07.

 

[fleischfresser]

Hi,

the stated requirement comes from Section VIII, Division 1, Paragraph UG-84(h)2()(-b) or Section VIII, Division 2, Paragraph 3.11.8.3(f)(2) and is therefore an addition to the variables of ASME IX and must be fulfilled if there are impact requirements for all P-No. until Edition 2021 and since Ed. 2023 not for P-No. 1.1 and 1.2.

The following heat treatment conditions of the base metal are considered equivalent heat treatment conditions:
• accelerated cooling from the normalizing temperature, followed by tempering
• normalized
• normalized and tempered

My opinion is supported by
Interpretation BPV VIII-1-20-07
Edition/Addenda: 2017
Para./Fig./Table No: UG–84(h)(2)(-b)
Subject Description: Base material heat treatment equivalent
Date Issued: 04/29/2020
Record Number: 17-2209
Question: Are materials that undergo accelerated cooling from the normalizing temperature, followed by tempering, as permitted by the material specification, considered to be in the same heat-treated condition as normalized or normalized and tempered heat-treated material?
Reply: Yes

Explanation
Figure UCS-66 General Note (e)(1) states that materials that undergo "cooling rates faster than those obtained by cooling in air" are equivalent to normalized or normalized and tempered material. This satisfies the requirement of UG-84(h)(2)(-b) that materials "be in the same heat-treated condition". Accelerated cooling is specifically addressed in material specifications such as SA-182, SA-213, SA-302, SA-335 and SA-387.

Regards - Juergen