Chromium Molybdenum (Cr-Mo) steel plate is a low-alloy structural steel engineered specifically for high-stress, high-temperature, and corrosive pressure vessel environments. The inclusion of Chromium (typically 0.5% to 9.0%) improves oxidation and corrosion resistance, while Molybdenum (0.5% to 1.1%) increases creep strength and high-temperature tensile capacity up to 600°C.
Supplied primarily under ASME SA387 / ASTM A387 and EN 10028-2 standards, these plates deliver microstructural stability for pressure vessels, industrial boilers, power plant heat exchangers, and heavy equipment parts.
Key Product Characteristics
High-Temperature Creep Resistance: Molybdenum stabilizes microstructures against thermal deformation under continuous stress above 450°C.
Hydrogen Embrittlement Resistance: Microalloying prevents internal cracking caused by high-pressure hydrogen gas in petrochemical refineries.
Elevated Tensile & Yield Performance: Retains high mechanical strength after post-weld heat treatment (PWHT) and tempering processes.
Oxidation Resistance: Chromium forms a passive oxide layer that resists scaling and oxidation in aggressive atmospheric or gas-fired environments.
Technical Specifications
|
Parameter |
Specification / Capability |
|
Thickness Range |
6 mm - 150 mm (up to 250 mm upon technical review) |
|
Width Range |
1,500 mm - 4,000 mm |
|
Length Range |
6,000 mm - 18,000 mm |
|
Delivery Conditions |
Normalized + Tempered (N+T), Quenched + Tempered (Q+T), Annealed |
|
Ultrasound Testing (UT) |
ASTM A435 / ASTM A578 Level A/B/C, EN 10160 S1E1/S2E2 |
|
Heat Treatment Protocols |
Simulated Post-Weld Heat Treatment (SPWHT) testing per project specifications |
|
Impact Testing |
Charpy V-Notch (CVN) down to -40°C or specified temperature |
Grades & Standards
|
Standard |
Main Grades |
Primary Focus / Performance Characteristic |
|
ASME / ASTM A387 |
Grade 11 Class 2, Grade 12 Class 2 |
Mid-temperature pressure vessels, balanced cost-to-performance ratio. |
|
ASME / ASTM A387 |
Grade 22 Class 2, Grade 91 Class 2 |
High-pressure boilers and hydrocrackers requiring high creep resistance. |
|
EN 10028-2 |
16Mo3, 13CrMo4-5, 10CrMo9-10 |
European pressure vessel applications and heat-resistant piping components. |
|
AISI / SAE |
4130, 4140, 4142 |
Structural, aerospace, oilfield machinery, and high-wear mechanical components. |
Surface & Processing Options
Surface Condition: Shot-blasted (Sa 2.5), oiled, mill scale, or coated with weldable shop primers.
Edge Processing: Mill edge, flame cut, plasma cut, or beveling for immediate welding prep.
Precision Cutting: CNC oxy-fuel cutting, laser cutting (thin plates), or waterjet cutting to tight tolerances (+/- 2 mm).
Machining Services: Drilling, edge profiling, bending, and stress relief heat treatment.
Applications
Hydrotreating reactors, catalytic cracking units, hydrogen storage tanks, and separator vessels.
Steam drums, high-pressure boilers, headers, superheater piping plates, and turbine components.
Subsea manifolds, high-pressure piping flanges, and offshore platform structures.
Hydraulic excavator arms, gearing mechanisms, drill collars, and heavy-duty structural parts.
Quality Control & Inspection
Every plate lot undergoes metallurgical control and traceable verification:
Chemical Analysis: Optical Emission Spectrometry (OES) to ensure tight controls on P, S, Sb, Sn, As, and Cu to mitigate temper embrittlement.
Mechanical Testing: Room and high-temperature tensile tests, yield point determination, and Charpy V-Notch impact testing.
Non-Destructive Testing (NDT): 100% Ultrasonic Testing (UT) to detect internal laminations or inclusions according to ASTM A578/A435.
Microstructure Analysis: Grain size verification (ASTM E112) and grain boundary stability check via N+T thermal simulation.
Traceability: EN 10204 3.1 or 3.2 Mill Test Certificates (MTC) supplied with full heat number correlation.
Supply & Customization Options
Custom Plate Dimensions
Non-standard thicknesses and widths tailored to minimize cutting scrap on vessel shell fabrication.
Trial Quantities & Stock
Large inventory of standard ASTM A387 Gr 11/22 plates for rapid delivery.
Third-Party Inspection (TPI)
Coordinated inspection handling with Lloyd's Register, TÜV, Bureau Veritas (BV), or DNV.
Export Packaging
Seaworthy packaging with anti-corrosion VCI paper, wooden skids, steel banding, and corner protectors.
What Buyers Should Provide for a Quote
To receive an accurate commercial and technical quote, please share:
Material Grade & Standard: (E.g., ASME SA387 Grade 22 Class 2 or EN 10028-2 13CrMo4-5
Dimensions & Quantity: Thickness x Width x Length (mm), along with total tonnage or piece count.
Heat Treatment Condition: (E.g., N+T, Q+T, or SPWHT requirement)
NDT & Inspection Levels: Ultrasonic testing standard (e.g., ASTM A578 Level B) and impact testing temperature requirement.
Secondary Processing: Edge beveling, cutting drawings, or surface coating requirements.
Delivery Terms & Destination Port: Incoterms (FOB, CFR, CIF) and targeted lead time.
FAQ
Q: How does ASME A387 Class 1 differ from Class 2?
A: Class 2 provides higher mechanical tensile and yield strength requirements than Class 1 for the same chemical grade, allowing designers to reduce vessel wall thickness under ASME pressure vessel codes.
Q: What is the main benefit of adding Molybdenum to Chromium steel plates?
A: Molybdenum prevents temper embrittlement, raises elevated temperature yield strength, and improves creep resistance under sustained mechanical loads above 450°C.
Q: Is post-weld heat treatment (PWHT) necessary for Cr-Mo steel plates?
A: A: Yes, PWHT is standard practice for Cr-Mo plates after welding to relieve residual stress, lower hard-zone peak hardness, and restore toughness across the Heat-Affected Zone (HAZ).
Q: What mill certificates are provided with shipment?
A: Standard shipments include EN 10204 3.1 MTC containing exact chemical heat analysis, mechanical test results, heat treatment history, and UT inspection results. Third-party EN 10204 3.2 certificates can be provided upon request.
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