The minimum Ti calculation for S32109 (321H) in ASTM A312 is 4xC. The minimum calculation for minimum Ti in the same grade in ASTM A240 is 4(C+N) minimum. ASTM A240 was changed from 4xC minimum to 4(C+N) minimum based upon data that indicated that the latter calculation more accurately ensured proper stabilization. We would propose to change ASTM A312 to the more accurate calculation. Additionally the maximum Ti in ASTM A312 for S32109 is .60 while the maximum in ASTM A240 for the same grade is .70. Raising the maximum N to the same level as ASTM A240 is based upon the addition of the N to the minimum calculation that will require higher Ti levels.
Keywordsaustenitic stainless steel; seamless steel pipe; stainless steel pipe; steel pipe; welded steel pipe;
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