Difference between S690QL and S620QL steel plate

Jan 09, 2026 Zostaw wiadomość

S690QL and S620QL are both high-strength, quenched & tempered (Q&T) structural steels under EN 10025-6, but the main difference lies in their specified minimum yield strength: S690QL has a higher minimum yield of 690 MPa, while S620QL has a minimum yield of 620 MPa, making S690QL stronger, with S690QL also typically offering better low-temperature toughness (QL for Low Temperature) for critical applications, though both use QL suffix for Q&T.

S620QL

	C			P	S	N	B
S620 QL	0.20	0.80	1.70	0.020-0.025	0.010-0.015	0.015	0.005	1.50
						V
	0.50	0.70	0.06	2.0	0.05	0.12	0.15

S690QL

max 0.2

max 0.8

max 1.7

max 2

max 0.02

max 0.01

max 1.5

max 0.7

max 0.12

max 0.015

max 0.06

max 0.05

max 0.5

max 0.15

max 0.005

max 0.83

	S620QL

S620 QL					-40	30J
	3<>	620	700-890	15	-40	30J
	50<>	580	700-890	15	-40	30J
	100<>	560	650-830	15	-40	30J

S690QL

	3 - 50	50 - 100	100 - 150
Rm - Tensile strength (MPa)	770-940	760-930	710-900

	3 - 50	50 - 100	100 - 150
ReH - Minimum yield strength (MPa)	690	650	630

KV - Impact energy (J) longitud.,

0℃
50

-20℃
40

-40℃
30

A - Min. elongation Lo=5,65 √ So (%)

S690QL

Strength: Higher strength, minimum yield strength of 690 MPa.

Application: Used for heavy-duty structures needing excellent strength-to-weight ratios, like cranes, bridges, and heavy machinery.

Toughness: Often tested to higher impact energy standards (like 40J at -20℃ or -40℃) due to the 'QL' (Quenched & Tempered, Low Temp) designation, suitable for very cold environments.

S620QL

Strength: Still high strength, but lower than S690QL, with a minimum yield strength of 620 MPa.

Application: Also for high-yield applications, but where slightly less strength than S690QL is sufficient.

Toughness: Also benefits from Q&T (QL), offering good impact properties, but its baseline yield is lower.