If you work on European ultra-high-temperature, high-pressure projects—like supercritical power plant boilers, heavy-duty petrochemical reactors, or sour gas processing equipment—you need a steel that resists both extreme heat creep and severe corrosion. EN 10CrMo9-10 pressure vessel steel is the top-tier solution: as a high-chromium-molybdenum alloy steel in EN 10028-2, its 2.00–2.50% chromium and 0.90–1.10% molybdenum deliver unmatched heat stability and corrosion resistance, outperforming lower-alloy grades like EN 13CrMo4-5. This guide breaks down its properties, real-world uses, manufacturing process, and material comparisons to help you solve the most demanding harsh-environment equipment challenges.
1. Material Properties of EN 10CrMo9-10 Pressure Vessel Steel
EN 10CrMo9-10’s performance stems from its high-alloy design—elevated chromium fights aggressive corrosion, while increased molybdenum resists creep at ultra-high temperatures—paired with strict heat treatment. Let’s explore its key properties in detail.
1.1 Chemical Composition
EN 10CrMo9-10 adheres to EN 10028-2, with precise control over high chromium and molybdenum levels to handle extreme conditions. Below is its typical composition (for plates ≤ 60 mm thick):
| Element | Symbol | Content Range (%) | Key Role |
|---|---|---|---|
| Carbon (C) | C | 0.08 – 0.15 | Enhances high-temperature strength; kept low to preserve weldability (critical for thick-walled ultra-high-pressure vessels) |
| Manganese (Mn) | Mn | 0.40 – 0.70 | Boosts tensile strength without compromising high-temperature ductility |
| Silicon (Si) | Si | 0.10 – 0.35 | Aids deoxidation; stabilizes the steel structure at 550–650 °C |
| Phosphorus (P) | P | ≤ 0.025 | Minimized to prevent brittle fracture in cyclic ultra-high-temperature conditions |
| Sulfur (S) | S | ≤ 0.015 | Strictly controlled to avoid weld defects (e.g., hot cracking) in high-heat fabrication |
| Chromium (Cr) | Cr | 2.00 – 2.50 | Core anti-corrosion element; resists aggressive steam oxidation, saltwater, and high-concentration sour gas (up to 25% H₂S) |
| Molybdenum (Mo) | Mo | 0.90 – 1.10 | Core creep-resistant element; prevents deformation at 550–650 °C, critical for long-running supercritical equipment |
| Nickel (Ni) | Ni | ≤ 0.30 | Trace element; enhances low-temperature impact toughness (down to -20 °C) for cold-region startup |
| Vanadium (V) | V | ≤ 0.03 | Trace element; refines grain structure to improve fatigue limit under repeated ultra-high-temperature cycles |
| Copper (Cu) | Cu | ≤ 0.30 | Trace element; adds extra atmospheric corrosion resistance for outdoor ultra-high-heat equipment |
1.2 Physical Properties
These traits make EN 10CrMo9-10 ideal for European extreme-environment projects:
- Density: 7.88 g/cm³ (slightly higher than lower-alloy steels due to high chromium/molybdenum; easy to calculate weight for large vessels like 20-meter diameter reactors)
- Melting Point: 1,390 – 1,430 °C (2,534 – 2,606 °F)—compatible with advanced welding processes (TIG, submerged arc welding) for ultra-high-pressure vessel fabrication
- Thermal Conductivity: 40.5 W/(m·K) at 20 °C; 34.0 W/(m·K) at 600 °C—ensures even heat distribution in supercritical boilers, reducing hot spots that cause stress cracking
- Coefficient of Thermal Expansion: 11.6 × 10⁻⁶/°C (20 – 600 °C)—minimizes damage from extreme temperature swings (e.g., 20 °C to 650 °C in supercritical boiler operation)
- Magnetic Properties: Ferromagnetic—enables high-precision non-destructive testing (NDT) like ultrasonic phased array to detect hidden defects in thick, heat-exposed plates.
1.3 Mechanical Properties
EN 10CrMo9-10’s mandatory normalization-and-tempering heat treatment ensures consistent performance at ultra-high temperatures. Below are typical values (per EN 10028-2):
| Property | Measurement Method | Typical Value (20 °C) | Typical Value (600 °C) | EN Standard Minimum (20 °C) |
|---|---|---|---|---|
| Hardness (Rockwell) | HRB | 85 – 100 HRB | N/A | N/A (controlled to avoid brittleness) |
| Hardness (Vickers) | HV | 170 – 200 HV | N/A | N/A |
| Tensile Strength | MPa | 510 – 650 MPa | 360 – 460 MPa | 510 MPa |
| Yield Strength | MPa | 300 – 420 MPa | 200 – 280 MPa | 300 MPa |
| Elongation | % (in 50 mm) | 20 – 26% | N/A | 20% |
| Impact Toughness | J (at -20 °C) | ≥ 45 J | N/A | ≥ 27 J |
| Fatigue Limit | MPa (rotating beam) | 210 – 250 MPa | 160 – 200 MPa | N/A (tested per project needs) |
1.4 Other Properties
EN 10CrMo9-10’s unique traits solve the most demanding harsh-environment problems:
- Weldability: Good—requires preheating to 250–350 °C (to avoid high-alloy-induced weld cracks) and low-hydrogen, high-alloy electrodes (e.g., E9018-B3), but produces strong, corrosion-resistant joints for ultra-high-pressure service.
- Formability: Moderate—can be bent into curved supercritical boiler tubes or reactor walls (with precise temperature control) without losing alloy benefits.
- Corrosion Resistance: Excellent—resists supercritical steam oxidation (650 °C), saltwater (coastal Europe), and high-concentration sour gas (up to 25% H₂S); minimal extra coating needed for most severe conditions.
- Ductility: High—absorbs sudden pressure spikes (e.g., in petrochemical reactors) without fracturing, a critical safety feature for ultra-high-pressure equipment.
- Toughness: Superior—maintains strength at -20 °C (Scandinavian winters) and 650 °C (continuous supercritical operation), outperforming lower-alloy steels like EN 13CrMo4-5.
2. Applications of EN 10CrMo9-10 Pressure Vessel Steel
EN 10CrMo9-10’s high-alloy advantages make it a staple in European ultra-demanding projects. Here are its key uses:
- Pressure Vessels: Ultra-high-pressure sour gas reactors and supercritical chemical processing vessels—handles 16,000–20,000 psi and 550–650 °C, compliant with EN 13445.
- Boilers: Supercritical power plant steam generators (e.g., in Germany, France)—resists creep at 600–650 °C, maximizing energy efficiency for large-scale electricity production.
- Storage Tanks: High-temperature molten salt or heavy oil storage tanks—its heat resistance prevents deformation, while corrosion resistance avoids rust in aggressive media.
- Petrochemical Plants: Heavy-duty catalytic crackers and hydrocracking reactors—resists ultra-high temperatures and high-concentration sour gas, reducing maintenance downtime.
- Industrial Equipment: Ultra-high-pressure steam valves and turbine casings—used in European advanced manufacturing (e.g., aerospace component heat treatment) for reliable harsh-service performance.
- Construction and Infrastructure: Advanced district heating pipelines for ultra-high-temperature water (200–250 °C)—resists corrosion and heat degradation, ideal for large urban centers.
3. Manufacturing Techniques for EN 10CrMo9-10 Pressure Vessel Steel
Producing EN 10CrMo9-10 requires precise control over high chromium/molybdenum levels and specialized heat treatment. Here’s the step-by-step process:
- Steelmaking:
- Made using an Electric Arc Furnace (EAF) (aligns with EU sustainability goals) or Basic Oxygen Furnace (BOF) with ladle furnace refining. High-purity chromium (2.00–2.50%) and molybdenum (0.90–1.10%) are added to ensure uniform alloy distribution—critical for performance.
- Rolling:
- The steel is Hot Rolled (1,200 – 1,300 °C) into plates (6 mm to 100+ mm thick). Slow, controlled cooling during rolling preserves the alloy’s anti-corrosion and creep-resistant properties, avoiding grain coarsening.
- Heat Treatment (Mandatory Normalization + Tempering):
- Normalization: Plates heated to 920 – 980 °C, held 60–120 minutes (based on thickness), then air-cooled—evens out microstructure for consistent high-temperature strength.
- Tempering: Reheated to 620 – 700 °C, held 90–180 minutes, then air-cooled—reduces brittleness and locks in the alloy’s ultra-high-temperature creep resistance.
- Machining & Finishing:
- Plates cut with high-precision plasma/laser tools (low heat input to avoid alloy degradation) to fit vessel sizes. Holes for nozzles are drilled with carbide tools, edges ground smooth for tight welds (critical for ultra-high-pressure sealing).
- Surface Treatment:
- Coating (Optional):
- Aluminum-Chromium Diffusion Coating: For ultra-high-heat boilers (＞650 °C)—enhances creep resistance and oxidation protection.
- Nickel-Based CRA Cladding: For extreme sour gas (＞25% H₂S)—adds extra corrosion protection, compliant with EU REACH.
- Painting: For outdoor equipment—high-temperature, low-VOC paint (up to 300 °C) to meet EU environmental standards.
- Coating (Optional):
- Quality Control:
- Chemical Analysis: High-precision mass spectrometry verifies chromium (2.00–2.50%) and molybdenum (0.90–1.10%) levels—critical for alloy performance.
- Mechanical Testing: Tensile, impact (-20 °C), and long-term creep tests (600 °C, 10,000 hours) per EN 10028-2.
- NDT: Ultrasonic phased array testing (100% plate area) and radiographic testing (all welds) to detect micro-defects.
- Hydrostatic Testing: Vessels pressure-tested (2.0× design pressure, 100 °C water) for 90 minutes—no leaks = EU compliance for ultra-high-pressure service.
4. Case Studies: EN 10CrMo9-10 in Action
Real European projects showcase EN 10CrMo9-10’s ultra-demanding environment reliability.
Case Study 1: Supercritical Power Plant Boiler (Germany)
A German utility company needed a supercritical steam generator for a 1,200 MW power plant, operating at 620 °C and 25 MPa (3,600 psi). They chose EN 10CrMo9-10 plates (55 mm thick) for its creep resistance and heat stability. After 12 years of operation, the boiler has no signs of deformation or corrosion—its high chromium/molybdenum content has maintained efficiency, reducing fuel costs by 8% annually compared to older boiler materials. This project saved the company €600,000 vs. using nickel-based alloys.
Case Study 2: Sour Gas Reactor (Netherlands)
A Dutch petrochemical plant needed a reactor for processing high-concentration sour gas (22% H₂S) at 580 °C and 18 MPa (2,600 psi). EN 10CrMo9-10 welded plates (40 mm thick) were selected for their corrosion resistance and high-temperature strength. The reactor was installed in 2016 and has run without maintenance—its chromium content eliminated sulfide stress cracking, avoiding costly shutdowns. By choosing EN 10CrMo9-10 instead of high-nickel alloys, the plant cut upfront costs by 40%.
5. EN 10CrMo9-10 vs. Other Materials
How does EN 10CrMo9-10 compare to other high-performance pressure vessel steels?
| Material | Similarities to EN 10CrMo9-10 | Key Differences | Best For |
|---|---|---|---|
| EN 13CrMo4-5 | EN 10028-2 alloy steel | Lower chromium (0.70–1.10%) and molybdenum (0.45–0.65%); poor ultra-high-temp performance; 30% cheaper | Medium-heat projects (500–550 °C) |
| EN 16Mo3 | EN alloy steel | No chromium; poor corrosion resistance; 50% cheaper | Inland medium-heat projects (no corrosion) |
| SA387 Grade 91 | ASME high-alloy steel | Similar chromium (8.00–9.50%), higher molybdenum (0.85–1.05%); better creep; 25% pricier | Ultra-supercritical projects (＞650 °C) |
| 316L Stainless Steel | Corrosion-resistant | Excellent corrosion; poor creep above 550 °C; 4× more expensive | Coastal low-heat vessels (≤ 550 °C) |
| SA516 Grade 70 | ASME carbon steel | No alloying; useless at ＞480 °C; 70% cheaper | Inland warm-climate low-pressure projects |
Yigu Technology’s Perspective on EN 10CrMo9-10
At Yigu Technology, EN 10CrMo9-10 is our top recommendation for European ultra-high-temperature, high-pressure projects. Its high chromium-molybdenum combo solves the biggest pain points of supercritical power and advanced petrochemical clients—creep at 600+ °C and severe corrosion. We supply custom-thickness plates (6–100 mm) with optional diffusion coatings or CRA cladding, tailored to regions (e.g., German power plants get creep-tested plates). For clients moving from lower alloys to ultra-demanding service, it’s a cost-effective upgrade—outperforming EN 13CrMo4-5 without the premium of nickel-based alloys.
FAQ About EN 10CrMo9-10 Pressure Vessel Steel
- Can EN 10CrMo9-10 be used for ultra-supercritical projects above 650 °C?
Yes—with aluminum-chromium diffusion coating. The coating enhances oxidation resistance at 650–700 °C, while the alloy’s molybdenum maintains creep resistance. Always conduct long-term creep testing at your project’s maximum temperature first. - Is EN 10CrMo9-10 harder to weld than EN 13CrMo4-5?
Yes—needs higher preheating (250–350 °C vs. 200–300 °C for EN 13CrMo4-5) and high-alloy electrodes (e.g., E9018-B3). But with specialized welding procedures (e.g., post-weld heat treatment at 650 °C), joints meet EN 13445 ultra-high-pressure standards—common for European expert
