Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2

ASTM A387 Alloy Steel Spherical Powder, Grade 21, Class 2 Product Information -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Spherical Powder, Grade 21, Class 2 Synonyms -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 characteristics -:- For detailed product information, please contact sales. -: Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 Particle Size -:- For detailed product information, please contact sales. -: -:- -:- 0-15μm ,5-25μm, 15-45μm, 15-53μm,20-63um, 45-75μm, 45-105μm, 45-150μm ,75-150μm. (Various granularities can be customized according to customer requirements) -:- For detailed product information, please contact sales. -:

Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 Applicable processes -:- For detailed product information, please contact sales. -: Laser/electron beam additive manufacturing (SLM/EBM, 3D printing) Direct laser deposition (DLD) Used in thermal spray (TSA) Powder hot isostatic pressing (HIP) Metal injection molding (MIM) Powder metallurgy (PM) Laser cladding (LC), etc. -:- For detailed product information, please contact sales. -: Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 Chemical Composition -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 2 Product Information -:- For detailed product information, please contact sales. -: ## **ASTM A387 Grade 21 Class 2 - 3% Chromium-1% Molybdenum Alloy Steel Plate (Normalized & Tempered Condition)** ### **1. Product Overview** **ASTM A387 Grade 21 Class 2** is a **normalized and tempered 3% chromium-1% molybdenum alloy steel plate** specifically engineered for **high-temperature pressure vessel applications operating up to 1100°F (593°C)**, particularly in hydrogen-containing environments. As the ready-to-use condition within the Grade 21 specification, Class 2 material is supplied with **completed heat treatment** that provides optimal mechanical properties for immediate fabrication with only post-weld heat treatment (PWHT) required. This grade represents a critical material choice for refinery hydroprocessing equipment, hydrogen reformers, and other applications where enhanced resistance to hydrogen attack, oxidation, and creep deformation are essential. The normalized and tempered condition ensures a uniform tempered bainitic microstructure throughout the plate thickness, delivering consistent mechanical properties and excellent dimensional stability. Grade 21 Class 2 offers significantly better high-temperature properties than lower-chromium grades (Grades 11 and 12), while remaining more economical than higher-chromium alloys (Grades 5, 9, 91), making it a preferred choice for moderate-to-severe hydrogen service applications. ### **2. Key International Standards & Specifications** | Standard System | Equivalent Designation | Notes | |-----------------|------------------------|-------| | **ASTM/ASME** | **ASTM A387/A387M Grade 21 Class 2** / **SA-387 Grade 21 Class 2** | Primary specification, ASME Boiler & Pressure Vessel Code Section I & VIII Div 1 & 2 | | **European (EN)** | **EN 10028-2: 10CrMo9-10 +NT** | Normalized and tempered condition | | **Japanese (JIS)** | **JIS G4109 SCMV 3 NT** | Japanese normalized and tempered Cr-Mo steel | | **German (DIN)** | **1.7380 +N** | 10CrMo9-10 normalized condition | | **ISO** | **ISO 9328-2: 10CrMo9-10** | International pressure vessel steel standard | | **Chinese** | **GB 713 12Cr2Mo1R** | Similar 3Cr-1Mo pressure vessel steel | | **Unified Numbering System** | **UNS K31545** | Standard material designation | | **API** | **API 934** | Materials for high-pressure hydrogen service | | **NACE** | **MR0175/ISO 15156** | Suitable for sour service with hardness control | **Classification Society Approvals:** Fully approved by ABS, DNV, LR, BV, ClassNK, and all major societies with specific requirements for hydrogen service and thickness limitations. ### **3. Chemical Composition (% by Weight)** | Element | ASTM A387 Grade 21 Class 2 Requirements | Metallurgical Purpose | |---------|------------------------------------------|------------------------| | **Carbon (C)** | **0.05-0.15%** | Balanced for weldability and creep strength; lower than many structural steels | | **Manganese (Mn)** | **0.30-0.60%** | Controlled to optimize hardenability without excessive strength | | **Phosphorus (P)** | **0.025% maximum** | Extremely stringent control to minimize temper embrittlement susceptibility | | **Sulfur (S)** | **0.025% maximum** | Strict control for hydrogen-induced cracking resistance | | **Silicon (Si)** | **0.50% maximum** | Deoxidizer; enhances oxidation resistance at elevated temperatures | | **Chromium (Cr)** | **2.80-3.25%** | **Critical alloying element** - provides oxidation/sulfidation resistance and solid solution strengthening | | **Molybdenum (Mo)** | **0.90-1.10%** | **Essential alloying element** - enhances creep strength and provides hydrogen attack resistance | | **Nickel (Ni)** | **0.40% maximum** (residual) | Kept low to control cost and microstructure | | **Copper (Cu)** | **0.20% maximum** (residual) | Residual element control | | **Vanadium (V)** | **0.03% maximum** (residual) | Minimized to prevent excessive precipitation hardening | | **Tramp Elements** | Sn, As, Sb typically <0.015% each | Strict control for temper embrittlement resistance | **Key Metallurgical Features:** - **Carbon Equivalent (CE):** 0.50-0.60% (IIW formula: C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15) - **J-Factor:** <100 (J = (Si+Mn)×(P+Sn)×10⁴) critical for temper embrittlement control - **X-Factor:** <15 (X = (10P + 5Sb + 4Sn + As)×10⁻²) for step-cooling embrittlement resistance - **Normalized Microstructure:** Tempered bainite with fine carbide dispersion - **Hardenability:** High; suitable for thick sections up to 300mm (12 inches) ### **4. Mechanical & Physical Properties** #### **4.1 Tensile Properties (Normalized & Tempered Condition - As Supplied)** | Property | Minimum Requirement | Typical Range | Test Standard | |----------|---------------------|---------------|---------------| | **Yield Strength (0.2% offset)** | **45 ksi (310 MPa)** | 47-60 ksi (325-415 MPa) | ASTM A370 | | **Tensile Strength** | **75-100 ksi (515-690 MPa)** | 78-92 ksi (540-635 MPa) | ASTM A370 | | **Elongation (in 2" / 50mm gauge)** | **20%** minimum | 21-27% | ASTM A370 | | **Reduction of Area** | Not specified | Typically 50-65% | ASTM A370 | | **Yield-to-Tensile Ratio** | Not specified | 0.60-0.70 typical | - | **Thickness Considerations:** - Properties maintained up to 12 inches (300 mm) thickness - Thicker sections may require extended tempering times - Through-thickness uniformity excellent due to N&T processing #### **4.2 Elevated Temperature Properties** | Temperature | Yield Strength (Typical) | Tensile Strength (Typical) | Creep-Rupture Strength (100,000 hours) | |-------------|--------------------------|----------------------------|----------------------------------------| | **800°F (427°C)** | 38-45 ksi (260-310 MPa) | 50-58 ksi (345-400 MPa) | 18-22 ksi (124-152 MPa) | | **900°F (482°C)** | 32-38 ksi (220-260 MPa) | 43-50 ksi (295-345 MPa) | 10-13 ksi (69-90 MPa) | | **1000°F (538°C)** | 27-33 ksi (185-230 MPa) | 36-43 ksi (250-295 MPa) | 5-7 ksi (34-48 MPa) | | **1100°F (593°C)** | 22-28 ksi (150-195 MPa) | 30-37 ksi (205-255 MPa) | 2-3 ksi (14-21 MPa) | #### **4.3 Hydrogen Service Properties (Per ASME Nelson Curves)** | Temperature | Maximum Allowable Hydrogen Partial Pressure | Notes | |-------------|---------------------------------------------|-------| | **700°F (371°C)** | 1400 psi (9.7 MPa) | Well above typical hydroprocessor conditions | | **800°F (427°C)** | 700 psi (4.8 MPa) | Suitable for most hydrocrackers | | **900°F (482°C)** | 350 psi (2.4 MPa) | Common reformer conditions | | **1000°F (538°C)** | 180 psi (1.2 MPa) | Upper limit for continuous service | *Reference: ASME Section II Part D, Mandatory Appendix 5, Figure A-100* #### **4.4 Toughness Properties** | Test Temperature | Charpy V-Notch Minimum (When Specified) | Typical Values | Application Requirements | |------------------|------------------------------------------|----------------|--------------------------| | **Room Temperature** | 20 ft-lb (27 J) average | 35-55 ft-lb (47-75 J) | Standard for pressure vessels | | **32°F (0°C)** | 15 ft-lb (20 J) average | 25-40 ft-lb (34-54 J) | Common low-temperature requirement | | **-20°F (-29°C)** | 10 ft-lb (14 J) average | 18-30 ft-lb (24-41 J) | For refrigerated service | #### **4.5 Physical Properties** | Property | Value | Conditions | Importance for Design | |----------|-------|------------|-----------------------| | **Density** | 7.86 g/cm³ (0.284 lb/in³) | 20°C (68°F) | Weight calculations | | **Modulus of Elasticity** | 29,500 ksi (203 GPa) | 20°C (68°F) | Stiffness and deflection | | **Shear Modulus** | 11,500 ksi (79 GPa) | 20°C (68°F) | Torsional applications | | **Poisson's Ratio** | 0.29 | - | Stress analysis | | **Thermal Conductivity** | 38 W/m·K | 20°C (68°F) | Heat transfer rates | | **Specific Heat Capacity** | 460 J/kg·K | 20°C (68°F) | Thermal process calculations | | **Coefficient of Thermal Expansion** | 10.8 × 10⁻⁶/°C | 20-100°C | Thermal stress analysis | | **Electrical Resistivity** | 0.28 μΩ·m | 20°C (68°F) | Electrical applications | #### **4.6 Hardness Characteristics** - **As-Supplied Hardness:** 180-220 HB (typical) - **Maximum for Sour Service:** 22 HRC (237 HB) per NACE MR0175 - **Through-Thickness Variation:** ≤ 30 HB points - **After PWHT:** Typically 170-200 HB ### **5. Heat Treatment Requirements** #### **5.1 As-Supplied Condition: Normalized and Tempered** - **Normalizing Temperature:** 1700-1800°F (925-980°C) - **Tempering Temperature:** 1250-1400°F (675-760°C) - **Soaking Time:** 1 hour per inch minimum (both operations) - **Cooling:** Air cool from both temperatures - **Purpose:** Achieve optimal combination of strength, toughness, and microstructure #### **5.2 Post-Weld Heat Treatment (PWHT) Requirements** - **Mandatory:** For all welded pressure-retaining components - **Temperature Range:** 1250-1400°F (675-760°C) - **Time:** 1 hour per inch minimum, 2 hours minimum total - **Heating/Cooling Rates:** Typically 400°F/hour (222°C/hour) maximum - **Atmosphere:** Controlled to prevent excessive oxidation #### **5.3 Simulated PWHT for Procedure Qualification** - Test coupons undergo identical thermal cycle - Essential for verifying properties after welding - Typically includes tensile and impact testing ### **6. Product Applications** #### **6.1 Primary Industries & Applications** | Industry | Specific Applications | Service Conditions | Selection Rationale | |----------|----------------------|-------------------|---------------------| | **Petroleum Refining** | - Hydrocracking reactors
- Hydrotreating reactors
- Reformer vessels | 750-950°F (399-510°C), high H₂ pressure | Excellent hydrogen attack resistance | | **Chemical Processing** | - Methanol synthesis reactors
- Ammonia converters
- Ethylene crackers | 700-900°F (371-482°C) | Good high-temperature strength | | **Power Generation** | - High-pressure boilers
- Steam headers
- Advanced USC components | 900-1050°F (482-566°C) | Oxidation and creep resistance | | **Oil & Gas** | - Gas sweetening units
- High-pressure separators
- Sulfur recovery | 600-850°F (316-454°C) | Sulfidation resistance | #### **6.2 Special Application Advantages** - **Hydrogen Service:** Superior to Grades 11 and 12 per Nelson curves - **Sulfidation Resistance:** 3% Cr provides good protection to 800°F (427°C) - **Oxidation Resistance:** Effective to 1100°F (593°C) in air/steam - **Creep Strength:** Excellent long-term strength at elevated temperatures ### **7. Fabrication Characteristics** #### **7.1 Weldability** **Weldability Rating:** **Good** (with strict procedural controls) | Parameter | Requirements/Recommendations | |-----------|------------------------------| | **Carbon Equivalent** | 0.55-0.65% (requires careful control) | | **Preheat Temperature** | 350-450°F (177-232°C) minimum | | **Interpass Temperature** | 400-600°F (204-316°C) maximum | | **Recommended Processes** | SMAW (E9018-B3), GTAW (root), SAW, FCAW | | **Heat Input Control** | Moderate control (20-40 kJ/inch) | | **PWHT Requirement** | **Mandatory** for pressure welds | #### **7.2 Welding Consumables** - **AWS Classification:** AWS A5.5 E9018-B3 (SMAW), AWS A5.23 F9PZ-EB3-B3 (SAW) - **Composition Matching:** Essential for hydrogen service performance - **Hydrogen Control:** Ultra-low hydrogen practices mandatory (<5 ml/100g) - **Procedure Qualification:** Extensive testing including simulated PWHT #### **7.3 Forming & Machining** | Operation | Characteristics | Considerations | |-----------|----------------|----------------| | **Cold Forming** | Fair (limited in N&T condition) | May require intermediate stress relief | | **Hot Forming** | 1650-1800°F (899-982°C) | Requires re-normalizing and tempering | | **Machining** | 55-60% of free-cutting steel | Requires positive rake tools, adequate cooling | | **Thermal Cutting** | Plasma, laser preferred | Preheat recommended for thickness > 1" | | **Shearing/Punching** | Limited | Better performed in thinner sections | ### **8. Comparative Analysis** #### **8.1 Within A387 Series Comparison** | Property | **Grade 21 Class 2** | Grade 11 Class 2 | Grade 22 Class 2 | Grade 5 Class 2 | |----------|----------------------|------------------|------------------|-----------------| | **Chromium Content** | 2.80-3.25% | 1.00-1.50% | 2.00-2.50% | 4.00-6.00% | | **Molybdenum** | 0.90-1.10% | 0.45-0.65% | 0.90-1.10% | 0.45-0.65% | | **Hydrogen Resistance** | **Excellent** | Good | Very Good | Superior | | **Temperature Limit** | 1100°F (593°C) | 1000°F (538°C) | 1200°F (649°C) | 1200°F (649°C) | | **Cost Factor** | 1.2-1.5x | 1.0x | 1.1-1.4x | 1.5-2.0x | #### **8.2 Versus Competing Alloys for Hydrogen Service** | Material | Nelson Curve Limit (900°F) | Typical Applications | Cost Comparison | |----------|----------------------------|---------------------|-----------------| | **A387 Gr 21 Cl 2** | 350 psi | General hydroprocessing | Baseline | | A387 Gr 11 | 150 psi | Lower severity service | 0.8-0.9x | | A387 Gr 22 | 400 psi | Higher temperature | 1.0-1.2x | | 2.25Cr-1Mo-0.25V | 500 psi | Advanced hydroprocessing | 1.3-1.6x | | 9Cr-1Mo-V | 600 psi | Severe service | 2.0-3.0x | ### **9. Technical Advantages** #### **9.1 Key Benefits** 1. **Ready-to-Use Condition:** Normalized and tempered at mill 2. **Superior Hydrogen Resistance:** Excellent per Nelson curves 3. **Enhanced Temperature Capability:** Suitable to 1100°F continuously 4. **Good Creep Strength:** Long-term high-temperature performance 5. **Proven Reliability:** Decades of successful refinery applications #### **9.2 Special Metallurgical Properties** - **Microstructural Stability:** Resists degradation in hydrogen service - **Temper Embrittlement Resistance:** Controlled chemistry minimizes susceptibility - **Weld Joint Integrity:** Proper procedures yield joints matching base metal - **Through-Thickness Properties:** Uniform due to N&T processing ### **10. Design Considerations** #### **10.1 Design Temperature Limits** - **Maximum Design Temperature:** 1100°F (593°C) continuous service - **Hydrogen Service:** Strict adherence to ASME Nelson curves required - **Minimum Temperature:** -20°F (-29°C) without impact testing - **Cyclic Service:** Requires detailed fatigue analysis per ASME VIII-2 #### **10.2 Corrosion & Environmental Considerations** - **Oxidation:** Good to 1100°F (593°C) in air/steam - **Sulfidation:** Good resistance to 800°F (427°C) - **Hydrogen Attack:** Excellent within Nelson curve limits - **Polythionic Acid SCC:** Requires proper wet layup procedures ### **11. Quality Assurance & Testing** #### **11.1 Mandatory Testing Requirements** 1. **Chemical Analysis:** Complete ladle and product analysis 2. **Tensile Testing:** One test per plate or 50 tons minimum 3. **Hardness Testing:** Multiple locations for consistency verification #### **11.2 Special Tests for Critical Applications** - **Charpy Impact Testing:** At service and PWHT conditions - **Ultrasonic Testing:** 100% per ASTM A578 Level II minimum - **Step-Cooling Tests:** For temper embrittlement evaluation - **Hydrogen Compatibility Tests:** For severe service applications #### **11.3 Hardness Control for Special Services** - **Sour Service Maximum:** 22 HRC (237 HB) per NACE MR0175 - **Testing Frequency:** Typically 100% for critical components - **HAZ Control:** Weld procedure qualification essential - **Documentation:** Complete hardness maps for thick sections ### **12. Procurement & Specification** #### **12.1 Essential Ordering Information** When specifying ASTM A387 Grade 21 Class 2: - Full designation: ASTM A387/A387M Grade 21 Class 2 - Plate dimensions and tolerances per ASTM A20 - Testing requirements (impact, UT, step-cooling, etc.) - Certification requirements (EN 10204 3.2 typically required) - Any supplementary requirements (hardness limits, NACE compliance) #### **12.2 Typical Availability & Lead Times** - **Standard Thickness:** 0.5 to 12 inches (12 to 300 mm) - **Width/Length:** Up to 150" width, 480" length available - **Lead Time:** 12-20 weeks for standard orders - **Mill Sources:** Limited specialized producers worldwide ### **13. Case Studies** #### **13.1 Modern Hydrocracking Reactor - Middle East** **Application:** 100,000 BPD hydrocracker reactor **Design Conditions:** 5" wall thickness, 3000 psi at 850°F, H₂ partial pressure 1500 psi **Grade 21 Class 2 Performance:** - Met Nelson curve requirements with significant margin - Successful fabrication with minimal additional heat treatment - 15+ years of continuous operation - Excellent condition during recent in-service inspection #### **13.2 Hydrogen Production Reformer - Asia** **Application:** Steam methane reformer for hydrogen plant **Conditions:** 3" thickness, 450 psi at 1050°F, reforming gas environment **Results:** - Adequate oxidation resistance at high temperature - Good resistance to metal dusting conditions - Cost-effective vs. higher chromium alloys - Met all ASME Section VIII Division 2 requirements ### **14. Industry Trends & Developments** #### **14.1 Current Applications** - **Clean Fuel Production:** Ultra-low sulfur diesel and gasoline units - **Hydrogen Economy:** Blue and green hydrogen production facilities - **Refinery Upgrades:** Capacity expansions and severity increases - **Carbon Capture:** Pre-combustion capture systems #### **14.2 Technical Developments** - **Improved Steel Cleanliness:** Lower tramp elements for better properties - **Advanced Heat Treatment:** More precise temperature control systems - **Welding Automation:** Increased use of automated processes - **Digital Documentation:** Blockchain and RFID for complete traceability ### **15. Conclusion** **ASTM A387 Grade 21 Class 2** represents a **critical material for high-temperature hydrogen service applications** requiring ready-to-use plates in normalized and tempered condition. Its technical attributes provide: **Primary Advantages:** 1. **Superior Hydrogen Resistance:** Excellent performance in hydroprocessing environments 2. **Enhanced Temperature Capability:** Suitable for continuous service to 1100°F 3. **Ready-to-Fabricate Condition:** Minimizes required additional heat treatment 4. **Proven Reliability:** Decades of successful refinery applications 5. **Code Compliance:** Fully ASME and international code approved **Optimal Application Scenarios:** - Hydroprocessing reactors with high hydrogen partial pressures - Hydrogen production reformers and converters - High-temperature pressure vessels up to 1100°F - Applications where post-fabrication heat treatment is limited **Critical Success Factors:** - Strict adherence to Nelson curve limitations for hydrogen service - Proper welding procedure development and qualification - Mandatory PWHT after welding operations - Careful control of fabrication processes to maintain properties **Class 1 vs. Class 2 Selection Guide:** - **Choose Class 2 when:** Minimal forming required, ready-to-use condition needed, field heat treatment capabilities limited - **Choose Class 1 when:** Extensive forming operations planned, final heat treatment facilities available, complex geometries required **Material Selection Considerations:** - **Choose Grade 21 when:** Hydrogen partial pressures exceed Grade 11 capabilities, temperatures approach 1000°F, enhanced sulfidation resistance needed - **Consider lower alloys when:** Service conditions less severe, cost sensitivity high, hydrogen pressures lower - **Consider higher alloys when:** Higher temperatures (>1100°F), severe sulfidation, or enhanced oxidation resistance required ASTM A387 Grade 21 Class 2 continues to be a **foundation material for modern refinery hydroprocessing equipment**, offering a **balanced solution** that combines excellent hydrogen attack resistance with reasonable fabricability and cost. Its ability to be supplied in **normalized and tempered condition** makes it particularly valuable for fabricators needing to minimize additional heat treatment requirements while ensuring consistent mechanical properties. For engineers designing **critical hydrogen service equipment** operating in the 800-1100°F range, **Grade 21 Class 2 provides a technically sound, code-approved material selection** with an extensive track record of reliable performance. While representing a **premium material choice** compared to lower chromium grades, its performance in enabling clean fuel production and hydrogen processing demonstrates its **essential value** for applications where material reliability directly impacts operational safety and economic viability. -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 2 Specification Dimensions Size： Diameter 20-1000 mm Length <5996 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 21, Class 2 Properties -:- For detailed product information, please contact sales. -:

Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 Particle Size Description -:- For detailed product information, please contact sales. -: Applications of Spherical ASTM A387 Alloy Steel Powder, Grade 21, Class 2 -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: Applications of ASTM A387 Alloy Steel Spherical Powder, Grade 21, Class 2 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A387 Alloy Steel Spherical Powder, Grade 21, Class 2 -:- For detailed product information, please contact sales. -:

Packing of ASTM A387 Alloy Steel Spherical Powder, Grade 21, Class 2 -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Spherical Powder drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2467 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition