FAQ's

What are the NACE MR0175 requirements for UNS S66220 and UNS S66286?

QUESTION:
Material S66286 may be used according Table A.26. In the note is written “UNS S66286 shall have a maximum hardness of 35 HRC and shall be in either the solution-annealed and aged or solution-annealed and double-aged condition.”.
According ASTM A638 and ASTM A453 is Grade 660 UNS S66286 and Grade 662 UNS S66220. But the heat treatment differs:
(UNS S66286) ASTM A638 Grade 660 type 1 and 2 Heat treatment: solution-annealed and aged, see ASTM A638 Table 3
ASTM A453 Grade A and B Heat treatment: solution-annealed and aged, see ASTM A453Table 4
ASTM A453 Grade C and D Heat treatment: solution-annealed and double aged condition, see ASTM A453Table 4
(UNS S66220) ASTM A638 Grade 662 Heat treatment: solution-annealed and double aged condition, see ASTM A638 Table 3
ASTM A453 Grade 662 A and B Heat treatment: solution-annealed and aged, see ASTM A453Table 4

Question 1: Regarding UNS S66286 and 15156-3 Table A.26, does this Table apply to bolting (ASTM A453) and bar (ASTM A638) materials?
Answer 1: The Table has no restrictions on product form. UNS S66286 is required by Table A.26 to be in the solution annealed and aged or solution annealed and double aged condition with a maximum hardness of 35 HRC.
Question 2: If ASTM A638 is included in 15156-3 Table A.26, then is UNS S66220 (Grade 662) also included in Table A.26.
Answer 2: 15156-3 Table A.26 only applies to UNS S66286; this Table does not include UNS S66220.

Reference MP Inquiry 2017-04 (NACE MR0175 Part 3 A.8 Table A.26

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