Difference between S500Q and S620Q steel plate

Dec 24, 2025 Leave a message

S500Q and S620Q are European standard (EN 10025-6) High Strength Low Alloy (HSLA) structural steel plates, known for their high yield strength (500 MPa for S500Q, 620 MPa for S620Q) and superior toughness, delivered in a Quenched & Tempered (Q+T) condition with excellent low-temperature impact properties, making them ideal for heavy construction, cranes, and machinery requiring strength and weldability.

Chemical Composition

Chemical composition of S500Q steel plate

C	Si	Mn	P	S	N	B	Cr
0.20	0.80	1.70	0.025	0.015	0.015	0.005	1.50
Cu	Mo	Nb	Ni	Ti	V	Zr
0.50	0.70	0.06	2.0	0.05	0.12	0.15

S620QChemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N	B	Cr
S620 Q	0.20	0.80	1.70	0.020-0.025	0.010-0.015	0.015	0.005	1.50
	Cu	Mo	Nb	Ni	Ti	V	Zr
	0.50	0.70	0.06	2.0	0.05	0.12	0.15

Mechanical Property

Mechanical properties for S500Q steel plate:

Yield Strength (Min Mpa)			Tensile Strength ( Mpa)
t≤50	50<t≤100	100<t	t≤50	50<t≤100	100<t
500	480	400	590-770	590-770	540-720

Grade	S620QMechanical Property
Grade	Thickness	Yield	Tensile	Elongation	Min Impact Energy
S620 Q	mm	Min Mpa	Mpa	Min %	-20	30J
	3<t≦50	620	700-890	15	-20	30J
	50<t≦100	580	700-890	15	-20	30J
	100<t≦150	560	650-830	15	-20	30J

Key Characteristics

Standard: EN 10025-6 (for Quenched & Tempered steels).

Delivery Condition: Must be supplied Quenched and Tempered (Q+T).

High Strength: S500Q has a minimum yield strength of 500 MPa, while S620Q has 620 MPa.

Low-Temperature Toughness: Both offer good impact energy at low temperatures (e.g., -20°C for S500Q, with 'L' variants for -40°C/QL, -70°C/QL1).

Applications: Used in welded, bolted, and riveted structures, heavy machinery, bridges, and cranes where high strength-to-weight is crucial.

S500Q vs. S620Q

S500Q: Min Yield 500 MPa, Tensile 590-770 MPa, good for -20°C impacts (S500QL for -40°C).

S620Q: Min Yield 620 MPa, higher strength than S500Q, also offers 'QL' and 'QL1' grades for enhanced low-temp toughness.