A387 Grade 22 Class 2 for Boiler Steel Plate

The A387 Grade 22 Class 2 – a grade of chromium-molybdenum alloy – is mainly intended for use in pressure vessels and welded boilers, which are designed for use in elevated temperature service.

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Product Description

1.What are the chemical composition of A387 Grade 22 Class2?

A387 Gr.22CL.2Chemical Composition
Grade	The Element Max(%)
Grade	C	Si	Mn	P	S	Cr	Mo
A387 Gr.22 Cl.2	0.04-0.15	0.50	0.30-0.60	0.035	0.035	1.88-2.62	0.85-1.15

2.What are the advantages of A387 Grade 22 Class 2?

Good Corrosion Resistance:Exhibits excellent performance in medium-temperature hydrogen-rich environments, effectively preventing various corrosion phenomena.

High Strength:As a steel plate for pressure vessels, its strength meets the service requirements of high-pressure vessels.

Low Temper Embrittlement:After appropriate heat treatment, it has low temper embrittlement, enhancing the toughness and reliability of the steel plate.

3.What are the differences between A387 Grade 22 Class 2 and other chromium-molybdenum alloy materials?

Material	A387 Grade 11 Class 2 (1.25Cr-0.5Mo)	A387 Grade 22 Class 2 (2.25Cr-1Mo)	A387 Grade 91 Class 2 (9Cr-1Mo-V-Nb)
Chromium Content	1.25%	2.25%	9% (with V/Nb microalloying)
High-Temperature Strength	Good up to ~540°C	Excellent up to ~593°C	Superior up to ~650°C
Creep Resistance	Moderate	High (due to higher Mo and Cr)	Ultra-high (fine-grained martensite + precipitates)
Oxidation Resistance	Moderate in steam/hydrogen	Strong resistance to H₂S/CO₂ corrosion	Best for severe oxidation (e.g., coal gasification)
Typical Applications	Steam boilers, heat exchangers	Petrochemical hydrogenation reactors	Ultra-supercritical power plant pipelines