ASTM A572 Grade 50 is classified as a High-Strength Low-Alloy (HSLA) steel under the ASTM standard. It is also commonly referred to as a high-tensile, low-alloy Ni-V steel, due to the controlled addition of alloying elements that enhance its mechanical performance.
The ASTM A572 specification covers four strength grades, among which Grade 50 is the most widely used. This low-alloy steel grade is extensively applied in structural engineering, heavy construction equipment, building frameworks, heavy anchoring systems, truck frames, and other applications where a high strength-to-weight ratio is critical.
ASTM A572 Grade 50 is typically manufactured in the form of steel plates, structural channels, and heavy steel beams, making it suitable for load-bearing and large-span structures.
Thanks to its combination of high yield strength, good weldability, and improved toughness, ASTM A572 Grade 50 helps engineers reduce overall material weight while maintaining structural safety and durability, which is especially important in modern infrastructure and transportation projects.
Chemical Composition of ASTM A572 Gr 50 Plate
|
Grade
|
C (t≤16mm)
|
Si
|
Mn
|
P
|
S
|
Cu
|
N
|
Mo
|
|
A572 Gr 50
|
0.23 max
|
0.40 max
|
1.35 max
|
0.04 max
|
0.05 max
|
-
|
-
|
-
|
|
S355JR
|
0.27 max
|
0.60 max
|
1.70 max
|
0.045 max
|
0.045 max
|
0.60 max
|
0.014 max
|
-
|
|
ST52-3
|
0.22 max
|
-
|
-
|
0.50 max
|
0.50 max
|
-
|
-
|
-
|
|
SM490B
|
0.20 max
|
0.55 max
|
1.60 max
|
0.035 max
|
0.035 max
|
-
|
-
|
-
|
|
Q345B
|
0.20 max
|
0.50 max
|
1.70 max
|
0.035 max
|
0.035 max
|
0.30 max
|
0.012 max
|
0.1 max
|
Mechanical Properties of ASTM A572 Grade 50 Plate
|
Grade
|
Yield strength ReH/(N/mm2) (t≤16mm) min
|
Tensile strength Rm/(N/mm2) (3mm≤t≤16mm)
|
Elongation A/%(3mm≤t≤40mm) min
|
Charpy V test
|
|
Temperature/℃
|
Impact energy (Longitudinal)/J min
|
|
A572 Gr 50
|
345
|
450
|
18
|
-
|
-
|
|
S355JR
|
355
|
470-630
|
22
|
20
|
27
|
|
ST52-3
|
355
|
490-630
|
22
|
0
|
27
|
|
SM490B
|
295
|
490-610
|
18
|
|
|
|
Q345B
|
345
|
470-630
|
20
|
20
|
34
|
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