ASTM A203 Grades A and E are nickel-alloy steel plates for welded pressure vessels, differing mainly in nickel content, with Grade A typically around 2.25% Ni (2% nickel steel) and Grade E around 3.25% Ni (3% nickel steel), both offering good toughness, especially at low temperatures, used in oil, gas, and chemical industries for equipment like heat exchangers and reactors, requiring normalization.
Chemical Composition
A203 Grade AChemical Composition | |||||
Grade | The Element Max (%) | ||||
C | Si | Mn | P | S | |
A203 Grade A | 0.17 | 0.13-0.45 | 0.78-0.88 | 0.035 | 0.035 |
A203 Grade EChemical Composition | |||||
Grade | The Element Max (%) | ||||
C | Si | Mn | P | S | |
A203 Grade E | 0.20 | 0.13-0.45 | 0.70-0.80 | 0.035 | 0.035 |
Mechanical Property
Mechanical Property of A203 Grade A steel plate | A203 Grade A |
Tensile strength, kis [MPa] | 65-85 [450-585] |
Yield strength, min, kis [MPa] | 37 [255] |
Elongation in 8 in. [200 mm], min, % | 15 |
Elongation in 2 in. [50 mm], min, % | 19 |
Mechanical Property of A203 Grade E steel plate | A203 Grade E |
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 |
Key Differences & Similarities
Nickel Content: The defining factor, Grade A is a "2% nickel" steel, while Grade E is a "3% nickel" steel, with specific percentages (e.g., Grade E: 3.25-3.75% Ni).
Application: Both are used for high-temperature pressure vessels, reactors, heat exchangers, and storage tanks in industries like oil & gas and chemical processing.
Mechanical Properties: They share similar toughness and strength characteristics, though Grade E's higher nickel content contributes to different performance at low temperatures.
Manufacturing: Both grades often require normalization (a heat treatment) and must meet strict chemical and mechanical tests, including tension and Charpy V-Notch impact tests.
