ASTM A202 Grade A and Grade B are chromium-manganese-silicon alloy steel plates for welded boilers and pressure vessels, differing mainly in their mechanical strength, with Grade B being stronger (85-110 ksi tensile) than Grade A (75-95 ksi tensile). Both share similar compositions but Grade B's processing results in higher yield and tensile strengths, making it suitable for higher pressure/temperature applications than Grade A.
Chemical Composition
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A202 Grade A Chemical Composition |
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Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
|
|
A202 grade A |
0.17 |
0.54-0.90 |
0.97-1.52 |
0.035 |
0.035 |
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A202 Grade B Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
|
|
A202 Grade B |
0.25 |
0.54-0.90 |
0.97-1.52 |
0.035 |
0.035 |
Mechanical Property
|
Grade |
|
A202 Grade A Mechanical Property |
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|
Thickness |
Yield |
Tensile |
Elongation |
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|
A202 grade A |
mm |
Min Mpa |
Mpa |
Min % |
|
6-50 |
310 |
515-655 |
19% |
|
|
50-100 |
310 |
515-655 |
16% |
|
|
Grade |
|
A202 Grade B Mechanical Property |
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|
Thickness |
Yield |
Tensile |
Elongation |
|
|
A202 Grade B |
mm |
Min Mpa |
Mpa |
Min % |
|
6-50 |
325 |
587-760 |
18% |
|
|
50-100 |
325 |
587-760 |
15% |
|
Key Differences & Similarities
Type: Both are chromium-manganese-silicon (Cr-Mn-Si) alloy steels for pressure vessels.
Application: Intended for welded boilers and pressure vessels, often in shipbuilding, petrochemical, and energy industries.
Composition: Chemically very similar, both containing Cr, Mn, and Si.
Strength: Grade B offers higher strength levels compared to Grade A.
Grade A: 75-95 ksi (515-655 MPa) Tensile Strength.
Grade B: 85-110 ksi (585-760 MPa) Tensile Strength.
Processing: Grade B is often used for more demanding conditions (higher pressure/temp), while Grade A might be used where lower strength is acceptable, though Grade B is generally more common.
Availability: Both grades are available as hot-rolled plates, often with options for normalization or stress relieving.
