ASTM A202 Grade B (Cr-Mn-Si) and ASTM A203 Grade B (Ni-alloyed) are distinct pressure vessel steels differing in composition, primarily A202's chromium-manganese-silicon for general use vs. A203's nickel content for better low-temperature toughness, both designed for boilers and pressure vessels but serving different service conditions, with A202 for higher temps and A203 for colder applications.
A202 Grade B Chemical Composition
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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 |
A203 Grade B Chemical Composition
|
A203 Grade B Chemical Composition |
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|
Grade |
The Element Max (%) |
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|
C |
Si |
Mn |
P |
S |
|
|
A203 Grade B |
0.17 |
0.13-0.45 |
0.78-0.88 |
0.035 |
0.035 |
A202 Grade B Mechanical Property
|
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% |
|
A203 Grade B Mechanical Property
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Mechanical Property of A203 Grade B steel plate |
A203 Grade B |
|
Tensile strength, kis [MPa] |
70-90[485-620] |
|
Yield strength, min, kis [MPa] |
40 [275] |
|
Elongation in 8 in. [200 mm], min, % |
17 |
|
Elongation in 2 in. [50 mm], min, % |
21 |
ASTM A202 Grade B
Type: Chromium-Manganese-Silicon (Cr-Mn-Si) alloy steel.
Application: Used for welded boilers and pressure vessels, generally for higher temperature service.
Properties: Offers good weldability and mechanical strength, often supplied normalized or stress-relieved.
ASTM A203 Grade B
Type: Nickel-alloyed steel, specifically for low-temperature service.
Application: Fabricated for low-temperature pressure vessels in industries like oil, gas, and power.
Properties: Enhanced toughness at low temperatures due to its nickel content, requiring killing and fine-grain practices.
Key Differences
Alloy Content: A202 uses Cr-Mn-Si, while A203 uses Nickel for specific low-temp properties.
Service Temperature: A202 is more for general/higher temps; A203 is specifically for low temperatures.
Standard: Both fall under ASTM standards for pressure vessel plates but are distinct materials.
