DK44
Mechanical
- Sep 20, 2017
- 196
When we use Dual certified material grades, what shall be the criteria.
Examples:
SA 516 gr 60 / 70
SA 387 Gr 11 Cl 1 / Cl 2
SA 387 Gr 12 Cl 1 / Cl 2
SA 240 Gr 304L / 304
SA 316 Gr 316L / 316
1. Does it mean, for the raw materials, the Chemical Composition shall not exceed maximum limits of Lower grade and Mechanical Properties shall not be lower than minimum limits of Higher grade.
2. In case of Austenitic stainless Steels, when Lower allowable stress are required to be used in the Design of Tube sheets , Bolted Covers and Girth Flanges, does it imply that we have to use lower allowable stress of Lower Grade or can we use lower allowable stress of Higher grade?
Examples:
SA 516 gr 60 / 70
SA 387 Gr 11 Cl 1 / Cl 2
SA 387 Gr 12 Cl 1 / Cl 2
SA 240 Gr 304L / 304
SA 316 Gr 316L / 316
1. Does it mean, for the raw materials, the Chemical Composition shall not exceed maximum limits of Lower grade and Mechanical Properties shall not be lower than minimum limits of Higher grade.
2. In case of Austenitic stainless Steels, when Lower allowable stress are required to be used in the Design of Tube sheets , Bolted Covers and Girth Flanges, does it imply that we have to use lower allowable stress of Lower Grade or can we use lower allowable stress of Higher grade?