Spherical ASTM A387 Alloy Steel Powder, Grade 7, Class 2

ASTM A387 Alloy Steel Spherical Powder, Grade 7, Class 2 Product Information -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel Spherical Powder, Grade 7, Class 2 Synonyms -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: Spherical ASTM A387 Alloy Steel Powder, Grade 7, Class 2 characteristics -:- For detailed product information, please contact sales. -: Spherical ASTM A387 Alloy Steel Powder, Grade 7, 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 7, 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 7, Class 2 Chemical Composition -:- For detailed product information, please contact sales. -: -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 7, Class 2 Product Information -:- For detailed product information, please contact sales. -: # **Product Introduction: ASTM A387 Grade 7 Class 2 Alloy Steel Plate** **ASTM A387 Grade 7 Class 2** is a premium-quality medium-high chromium-molybdenum alloy steel plate designed for **critical high-temperature pressure vessel applications**. The "Grade 7" designation indicates a composition of **7-9% Chromium and 0.9-1.1% Molybdenum**, while "Class 2" specifies that the material is supplied in the **Normalized and Tempered (N&T) heat treatment condition** directly from the steel mill. This pre-conditioning ensures optimal and consistent mechanical properties, superior toughness, and enhanced microstructural stability compared to the as-rolled Class 1 condition. This material is engineered for service where **maximum reliability, impact resistance, and predictable high-temperature performance** are non-negotiable, particularly in severe petrochemical, refining, and power generation applications. --- ## **1. Key International Standards** * **Primary Material Standard:** **ASTM A387/A387M** - Standard Specification for Pressure Vessel Plates, Alloy Steel, Chromium-Molybdenum * **Common Supplementary Standards:** * **ASTM A20/A20M:** General Requirements for Steel Plates for Pressure Vessels * **ASME Section II, Part A:** Adopted as **SA-387 Grade 7 Class 2** in the ASME Boiler and Pressure Vessel Code * **EN 10028-2:** Comparable European standard is **P7** (1.7317), typically supplied normalized and tempered * **ISO 9328-2:** International specification for pressure vessel steels --- ## **2. Chemical Composition (Weight %, ASTM A387)** *Identical to Grade 7 Class 1 in composition, differing only in heat treatment state.* | Element | Composition (%) | Primary Function | |---------|----------------|------------------| | Carbon (C) | 0.15 max | Controls strength and hardenability | | Manganese (Mn) | 0.30-0.60 | Enhances strength and hardenability | | Phosphorus (P) | 0.035 max | Impurity control (toughness) | | Sulfur (S) | 0.035 max | Impurity control (inclusions) | | Silicon (Si) | 0.50-1.00 | Deoxidizer, strengthens ferrite | | **Chromium (Cr)** | **7.00-9.00** | **Provides oxidation/sulfidation resistance** | | **Molybdenum (Mo)** | **0.90-1.10** | **Enhances high-temperature strength and creep resistance** | *Note: The higher molybdenum content (compared to Grade 5) significantly improves creep strength at temperatures above 550°C (1020°F).* --- ## **3. Mechanical & Physical Properties (Class 2, N&T Condition)** ### **Mechanical Properties (Minimum/Average):** - **Tensile Strength:** **415-585 MPa** (60,000-85,000 psi) - **Yield Strength (min):** **240 MPa** (35,000 psi) *[Higher than Class 1 minimum of 205 MPa]* - **Elongation in 2 in. (50 mm):** 18% minimum - **Reduction of Area:** Typically 50-60% - **Hardness Range:** 180-230 HB (Brinell) - **Charpy V-Notch Impact Toughness:** Typically 40-60 J (30-44 ft-lb) at 21°C (70°F) – **significantly better than Class 1** ### **Physical Properties:** | Property | Value | Notes | |----------|-------|-------| | Density | 7.80 g/cm³ (0.282 lb/in³) | Slightly lower than carbon steel | | Modulus of Elasticity | 200 GPa (29×10⁶ psi) | 21°C (70°F) | | Thermal Conductivity | 34-37 W/m·K | At 100°C (212°F) | | Specific Heat | 470 J/kg·K | At 100°C (212°F) | | Thermal Expansion Coefficient | 11.1×10⁻⁶/K | 20-100°C (68-212°F) | | Electrical Resistivity | 0.58 μΩ·m | Room temperature | --- ## **4. Key Characteristics & Advantages (Compared to Class 1)** ### **Superior Mechanical Properties:** - **Enhanced Toughness:** The N&T microstructure provides excellent notch toughness and fracture resistance, critical for thick-section components and low-temperature startup conditions - **Higher Guaranteed Yield Strength:** Minimum 240 MPa vs. 205 MPa for Class 1 - **Property Uniformity:** Consistent mechanical properties through thickness and across the plate - **Improved Microstructural Stability:** Tempered bainitic structure resorts to degradation during long-term high-temperature exposure ### **Fabrication Benefits:** - **Predictable Behavior:** Known baseline properties simplify engineering calculations and fabrication planning - **Reduced Fabricator Heat Treatment:** For components not requiring extensive hot forming, only Post-Weld Heat Treatment (PWHT) may be needed - **Better Weldability Consistency:** More homogeneous base metal responds more predictably to welding thermal cycles ### **High-Temperature Performance:** - **Oxidation Resistance:** Effective up to approximately **650°C (1200°F)** due to chromium content - **Creep Rupture Strength:** Excellent resistance to deformation under stress at elevated temperatures - **Thermal Fatigue Resistance:** Good resistance to crack initiation under thermal cycling --- ## **5. Product Applications** Grade 7 Class 2 is specified for the most demanding applications where the **combination of high temperature, pressure, and corrosion potential** necessitates premium material properties: ### **Primary Applications:** #### **Petrochemical & Refining:** - **Hydrocracker Reactors:** Critical reactor shells and internals for severe service - **Catalytic Reformer Reactors:** High-temperature, hydrogen-rich environments - **High-Pressure Hot Separators:** In hydroprocessing units - **Sulfur Plant Reactors:** Equipment handling corrosive process streams - **Transfer Lines & Headers:** For high-temperature, high-pressure service #### **Power Generation:** - **High-Temperature Steam Piping:** Main steam lines and headers (thick-section applications) - **Heat Recovery Steam Generators (HRSGs):** High-temperature modules and superheater sections - **Fossil Power Plant Components:** Steam drums, manifolds, and critical pressure parts #### **Chemical Processing:** - **High-Pressure Reactors:** For processes involving corrosive catalysts - **High-Temperature Heat Exchangers:** Shells and channel covers - **Synthesis Reactors:** In ammonia, methanol, and other chemical production --- ## **6. Heat Treatment & Fabrication Guidelines** ### **Mill Heat Treatment (Class 2 Condition):** - **Normalizing:** 925-1000°C (1700-1830°F) followed by air cooling - **Tempering:** 650-750°C (1200-1380°F) for appropriate time - **Resulting Structure:** Tempered bainite with optimal strength-toughness combination ### **Fabrication Heat Treatment Requirements:** #### **Welding:** - **Essential Preheating:** **200-300°C (400-570°F)** minimum, maintained during welding - **Interpass Temperature Control:** 250-350°C (480-660°F) - **Filler Metal Selection:** AWS A5.5 E90XX-B9 or AWS A5.28 ER90S-B9 - **Strict Low-Hydrogen Practice:** Electrodes must be properly baked and stored #### **Post-Weld Heat Treatment (PWHT):** - **Mandatory Requirement:** Must be performed after welding - **Temperature Range:** **680-730°C (1256-1346°F)** – **must not exceed the original tempering temperature** - **Soaking Time:** Typically 1 hour per inch (25 mm) of thickness, minimum 1 hour - **Heating/Cooling Rates:** Controlled to minimize thermal stresses (usually ≤200°C/h or 360°F/h) #### **Important Fabrication Considerations:** 1. **Temperature Monitoring:** Critical during all thermal operations 2. **Avoid Over-Tempering:** PWHT temperature must be carefully controlled below the original tempering temperature 3. **Forming Limitations:** If hot forming exceeds approximately 925°C (1700°F), re-normalizing and tempering may be required 4. **Non-Destructive Testing:** Recommended after fabrication and PWHT --- ## **7. Comparison with Related Grades** | Aspect | Grade 7 Class 2 vs. Grade 7 Class 1 | Grade 7 Class 2 vs. Grade 5 Class 2 | Grade 7 Class 2 vs. Grade 9 Class 2 | |--------|--------------------------------------|-------------------------------------|-------------------------------------| | **Condition** | N&T from mill | N&T from mill | N&T from mill | | **Yield Strength** | Higher guaranteed minimum | Similar minimum | Higher (≥415 MPa for Grade 9) | | **Toughness** | Superior | Comparable or better | Generally higher | | **Temperature Limit** | ~650°C | ~600°C | ~700°C | | **Oxidation Resistance** | Better than Grade 5 | Good | Superior | | **Cost Factor** | Higher than Class 1 | Higher than Grade 5 | Lower than Grade 9 | | **Fabrication Complexity** | Less than Class 1 | More than Grade 5 | Similar to Grade 7 | --- ## **8. Design & Selection Considerations** ### **When to Specify Grade 7 Class 2:** 1. **Thick-Section Components:** Where through-thickness properties are critical 2. **High-Temperature Hydrogen Service:** Where both strength and corrosion resistance are needed 3. **Cyclic Service:** Applications with frequent temperature/pressure cycling 4. **Low-Temperature Exposure:** Components subject to low-temperature startup/shutdown 5. **Critical Pressure Parts:** Where maximum reliability is required ### **Economic Considerations:** - **Higher Initial Cost** than Class 1 but potentially **lower total fabrication cost** due to simplified heat treatment requirements - **Lifecycle Cost Benefits:** Extended service life in aggressive environments - **Insurance Advantages:** Often preferred by insurers for critical equipment --- **Technical Summary:** ASTM A387 Grade 7 Class 2 represents the premium supply condition for 7-9% chromium alloy steel, offering guaranteed optimized properties for demanding high-temperature pressure vessel service. The mill-applied normalized and tempered condition provides designers with greater certainty in mechanical performance, particularly toughness and strength uniformity, while offering fabricators a more consistent and predictable material for construction of critical process equipment. Proper attention to welding and heat treatment procedures remains essential to maintain the inherent quality of this high-performance material. -:- For detailed product information, please contact sales. -: ASTM A387 Alloy Steel, Grade 7, Class 2 Specification Dimensions Size： Diameter 20-1000 mm Length <6004 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 7, Class 2 Properties -:- For detailed product information, please contact sales. -:

Spherical ASTM A387 Alloy Steel Powder, Grade 7, Class 2 Particle Size Description -:- For detailed product information, please contact sales. -: Applications of Spherical ASTM A387 Alloy Steel Powder, Grade 7, 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 7, Class 2 -:- For detailed product information, please contact sales. -: Chemical Identifiers ASTM A387 Alloy Steel Spherical Powder, Grade 7, Class 2 -:- For detailed product information, please contact sales. -:

Packing of ASTM A387 Alloy Steel Spherical Powder, Grade 7, 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 2475 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