ASTM A514 Grade A and Grade Q are both high-strength, quenched and tempered alloy steel plates, but they differ in their specific chemical composition and mechanical properties, particularly hardness and toughness requirements, with Grade Q generally offering higher strength and specific low-temperature toughness, making it suitable for demanding structural applications like cranes and heavy equipment, while Grade A also provides high strength but with slightly different property balances, used for similar heavy-duty structural uses.
Chemical Composition of A514 Grade a
|
Element |
Composition (%) |
|---|---|
|
Carbon (C) |
0.15-0.21 |
|
Manganese (Mn) |
0.80-1.10 |
|
Phosphorus (P) |
0.035 max |
|
Sulfur (S) |
0.035 max |
|
Silicon (Si) |
0.40-0.80 |
|
Chromium (Cr) |
0.50-0.80 |
|
Molybdenum (Mo) |
0.18-0.28 |
|
Zirconium (Zr) |
0.05-0.15 |
|
Boron (B) |
0.0025 max |
Chemical Composition of A514 Grade Q
|
Element |
Heat Analysis (%) |
Product Analysis (%) |
|---|---|---|
|
C (Carbon) |
0.14–0.21 |
0.12–0.23 |
|
Mn (Manganese) |
0.95–1.30 |
0.91–1.34 |
|
P (Phosphorus, max) |
0.035 |
0.043 |
|
S (Sulfur, max) |
0.035 |
0.043 |
|
Si (Silicon) |
0.15–0.35 |
0.10–0.40 |
|
Ni (Nickel) |
1.20–1.50 |
1.15–1.55 |
|
Cr (Chromium) |
1.00–1.50 |
0.95–1.55 |
|
Mo (Molybdenum) |
0.40–0.60 |
0.37–0.63 |
|
V (Vanadium) |
0.03–0.08 |
0.01–0.10 |
|
B (Boron) |
0.0005–0.005 |
0.0000–0.0055 |
Mechanical Propertie of A514 Grade A
|
Property |
Requirement |
Test Direction |
|---|---|---|
|
Yield Strength (MPa) |
≥ 690 |
Longitudinal |
|
Tensile Strength (MPa) |
760–895 |
Longitudinal |
|
Elongation (%) |
≥ 18 |
Longitudinal |
|
Charpy V-Notch Impact (J @ -50°C) |
≥ 27 J |
Longitudinal |
|
Hardness (HBW) |
235 – 293 |
- |
Mechanical Propertie of A514 Grade q
|
Thickness (inches) |
Yield Strength (min, ksi) |
Tensile Strength (ksi) |
Elongation (min, %) |
|---|---|---|---|
|
Up to 2.5 |
100 |
110-130 |
18 |
|
2.5 to 6 |
90 |
100-130 |
16 |
Key Differences
Grade Q: Known for exceptional toughness, especially at low temperatures (often with specified Charpy V-notch impact tests), offering high yield strength (e.g., 100 ksi) and good formability for heavy-duty uses like crane booms and trailers.
Grade A: Also a high-strength Q&T steel (like T1 steel), providing excellent strength and weldability, used in heavy construction and machinery but with distinct property sets compared to Q.
