What are difference P500QL1 and P500QL2 steel plate？

Dec 10, 2025 Leave a message

P690QL1 and P690QL2 are high-strength, weldable, fine-grain steel grades specified under European standard EN 10028-6 for pressure vessels and high-temperature equipment, with the "P690" indicating a minimum yield strength of 690 MPa, while the suffixes "QL1" and "QL2" denote their suitability for low-temperature toughness, specifically tested at -40°C (QL1) and -60°C (QL2) respectively, both requiring 27 Joules of impact energy, making them ideal for demanding structural applications.

Chemical Composition

S690QL1Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N	B	Cr
S690 QL1	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

Carbon Equivalent: Ceq = 【C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15】%

P690QL2 Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N	B
P690QL2	0.20	0.80	1.70	0.020	0.010	0.015	0.005
	Mo	Cu	Nb	Ni	Ti	V	Cr
	0.70	0.3	0.06	2.50	0.05	0.12	1.50

Carbon Equivalent: Ceq = 【C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15】%

Mechanical Property

Grade	S690QL1Mechanical Property
Grade	Thickness	Yield	Tensile	Elongation	Min Impact Energy
S690 QL1	mm	Min Mpa	Mpa	Min %	-60	30J
	3<t≦50	890	940-1100	11	-60	30J
	50<t≦100	830	880-1100	11	-60	30J
	100<t≦150	800	820-1000	11	-60	30J

Grade	P690QL2 Mechanical Property
Grade	Thickness	Yield	Tensile	Elongation
P690QL2	mm	Min Mpa	Mpa	Min %
	6-50	690	770-940	14%
	50-100	670	770-940	14%
	100-150	630	720-900	14%

Key Characteristics
Standard: EN 10028-6 (Weldable fine grain steels for pressure purposes, quenched and tempered).
Application: High-temperature equipment, boilers, and pressure vessels.
Delivery Condition: Quenched and Tempered (Q+T).
Strength: P500 indicates a minimum yield strength of 500 MPa (for certain thicknesses).
The "QL1" vs. "QL2" Difference
Q: Denotes Quenched & Tempered (Q+T).
L1: Indicates a low-temperature impact test performed at -40°C, requiring a minimum impact energy of 27 Joules (J).
L2: Indicates a lower low-temperature impact test performed at -60°C, also requiring 27J, making it for colder environments.
In Summary
If you need a pressure vessel steel for general high-temperature use, P500QL1 is suitable; if your application involves much colder conditions, such as deep-sea equipment, P500QL2 is the preferred choice due to its enhanced low-temperature toughness.