ASTM A285 Grades B and C are carbon steel plates for pressure vessels, with Grade C being stronger than Grade B, offering higher tensile strength (380-515 MPa) and yield strength (205 MPa min) but slightly lower elongation, while Grade B has intermediate strength (345-485 MPa tensile, 185 MPa min yield) and elongation, with Grade C also having higher maximum carbon content (0.28% vs 0.22%). The primary difference lies in their mechanical properties, with strength increasing from A to B to C, making C suitable for more demanding applications.
Chemical Composition of A285 Grade B
|
Element |
Composition (%) |
|---|---|
|
Carbon (C) |
0.22 max |
|
Manganese (Mn) |
0.90 max |
|
Phosphorus (P) |
0.035 max |
|
Sulfur (S) |
0.035 max |
Chemical Composition of A285 Grade C
|
Element |
Composition (%) |
|---|---|
|
Carbon (C) |
0.28 max |
|
Manganese (Mn) |
0.98 max |
|
Phosphorus (P) |
0.035 max |
|
Sulfur (S) |
0.035 max |
Mechanical Properties of A285 Grade B
|
Property |
Value |
|---|---|
|
Tensile Strength |
50-70 ksi (345-485 MPa) |
|
Yield Strength |
27 ksi (185 MPa) min |
|
Elongation (in 200mm) |
25% min |
|
Elongation (in 50mm) |
28% min |
Mechanical Properties of A285 Grade C
| Grade | ASTM A285 grade C steel Mechanical Property | ||||
| Tensile Strength(MPa) | Yield Strength(MPa) | % Elongation in 2 in.(50mm) min | Impacting Test Temperature(°C) | ||
| A285 grade C | 380-515 | 205 | 25 | -20, -40, -60 | |
Key Differences (A285 Grade B vs. Grade C)
Strength: Grade C is stronger than Grade B, with higher minimum yield strength and tensile strength ranges.
Tensile Strength:
Grade B: 345-485 MPa (50-70 ksi).
Grade C: 380-515 MPa (55-75 ksi).
Yield Strength (min):
Grade B: 185 MPa (27 ksi).
Grade C: 205 MPa (30 ksi).
Elongation (in 8 in/200mm, min):
Grade B: 25%.
Grade C: 23%.
Carbon Content (max):
Grade B: 0.22%.
Grade C: 0.28%.
Applications & Usage
Both grades are used in pressure vessel construction. Grade C, with its higher strength, is often used for more demanding, higher pressure/temperature applications, while Grade B provides a good balance for general use, and Grade A for lower-stress needs.
