Difference between P460Q and P460QH steel plate

Dec 22, 2025 Leave a message

The main difference is that P460Q is a general high-strength fine-grain steel, while P460QH (and P460QL1/2) signifies specific low-temperature toughness requirements (e.g., -20°C for Q, -40°C for QL1, -60°C for QL2) with defined impact energy tests (like 27J), making P460QH better suited for cryogenic or cold-service pressure vessels, both meeting EN 10028-6 standards for boilers and pressure vessels.

Here's a breakdown of the designations:

P (Plate): Indicates it's a plate product.

460 (Yield Strength): Denotes a minimum yield strength of 460 MPa.

Q (Quenched & Tempered): Means the steel is heat-treated (quenched and tempered) for improved strength and toughness.

H / L1 / L2 (Toughness Level): This suffix specifies the Charpy impact test temperature:

P460Q: Basic -20°C impact test.

P460QH: Higher quality for low temperatures, often -20°C with 27J impact.

Chemical Composition

P460Q Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N	B
P460Q	0.18	0.50	1.70	0.025	0.015	0.015	0.005
	Mo	Cu	Nb	Ni	Ti	V	Zr
	0.50	0.3	0.05	0.5	0.03	0.06	0.05

P460QH Chemical Composition
Grade	The Element Max (%)
Grade	C	Si	Mn	P	S	N	B
P460QH	0.18	0.50	1.70	0.025	0.015	0.015	0.005
	Mo	Cu	Nb	Ni	Ti	V	Zr
	0.50	0.3	0.05	0.5	0.03	0.06	0.05

Mechanical Property

Grade	P460QH Mechanical Property
Grade	Thickness	Yield	Tensile	Elongation
P460QH	mm	Min Mpa	Mpa	Min %
	6-50	460	550-720	19%
	50-100	440	550-720	19%
	100-150	400	500-670	19%

Grade	P460Q Mechanical Property
Grade	Thickness	Yield	Tensile	Elongation
P460Q	mm	Min Mpa	Mpa	Min %
	6-50	460	550-720	19%
	50-100	440	550-720	19%
	100-150	400	500-670	19%

In essence: Both are strong, weldable steels for boilers/pressure vessels, but the "H" (or "L1", "L2") in P460QH adds a crucial requirement for guaranteed performance at very low temperatures, making it more specialized for cold-service applications than the base P460Q.