Thank you RK,

I saw method in UG-28(c)(2)Step3 is for pipe with D/t < 10. Can I still use it even if D /t > 10?


And Ibrahim,
Sy at 600'C is about 40ksi from the brochure. But this value is larger than min. yield strength of 35ksi at 70'F(21'C) from Table Y-1. That's my headache.