Overview SA 537 Cl 1 & SA 537 Cl 2
This grade is commonly used in pressure vessel applications where low temperature resistance to notch sensitivity is needed and added strength levels are needed. Class 1 is normalized and the tensile is in the 70,000 – 90,000 level. Class 2 is quenched and tempered with a tensile range of 80,000 – 100,000. Minimum yield strength for class 1 is 50,000 and for class 2 is 60,000.
Chemical Requirements
*Elements represented in percentage
| Element | Composition % |
|---|---|
| Carbon, max | 0.24 |
| Manganese: | |
| 1 1/2in. (40 mm) and under in thickness | |
| Heat analysis | 0.70-1.35 |
| Product analysis | 0.64-1.46 |
| Over 1 1/2in. (40 mm) in thickness | |
| Heat analysis | 1.00-1.60 |
| Product analysis | 0.92-1.72 |
| Phosphorus, max | 0.025 |
| Sulfur, max | 0.025 |
| Silicon | |
| Heat analysis | 0.15-0.50 |
| Product analysis | 0.13-0.55 |
| Copper, max: | |
| Heat analysis | 0.35 |
| Product analysis | 0.38 |
| Nickel, max: | |
| Heat analysis | 0.25 |
| Product analysis | 0.28 |
| Chromium, max: | |
| Heat analysis | 0.25 |
| Product analysis | 0.29 |
| Molybdenum, max: | |
| Heat analysis | 0.08 |
| Product analysis | 0.09 |
Tensile Requirements
| SA 537 Class 1 ksi(MPa) |
SA 537 Class 2 ksi (MPa) |
|
|---|---|---|
| Tensile strength, ksi (MPa) | ||
| 2-1/2 in. and under | 70-90 | 80-100 |
| (65mm and under) | (485-620) | (550-690) |
| Over 2-1/2 to 4 in., incl | 65-85 | 75-95 |
| (Over 65 to 100 mm, incl) | (450-585) | (515-655) |
| Over 4 to 6 in., incl | … | 70-90 |
| (Over 100 to 150 mm, incl) | … | (485-620) |
| Yield strength, min. | ||
| 2-1/2 in. and under | 50 | 60 |
| (65mm and under) | (345) | (415) |
| Over 2-1/2 to 4 in., incl | 45 | 55 |
| (Over 65 to 100 mm, incl) | (310) | (380) |
| Over 4 to 6 in., incl | … | 46 |
| (Over 100 to 150 mm, incl) | … | (315) |
| Elongation in 2 in. | ||
| (50 mm), min. % | ||
| 4 in. (100 mm) and under | 22 | 22 |
| Over 4 in. (100 mm) | … | 20 |
| Elongation in 8 in. | ||
| (200 mm), min, % | 18 | … |