SA 387 Grade 5 Class 1 refers to a specific grade of chromium-molybdenum alloy steel plate defined by the ASME Boiler and Pressure Vessel Code (SA 387) or ASTM A387. It is designed primarily for use in weldable pressure vessels and boilers operating at elevated temperatures.
Chemical Composition
| Grade | C | Si | Mn | P | S | Cr | Mo |
| SA387 GR.5 CL.1 | 0.15 max | 0.55 max | 0.25-0.66 max | 0.035 max | 0.035 max | 3.90-6.10 max | 0.40-0.70 max |
Mechanical Properties
| Grade | SA387 GR.5 CL.1 | |||
| SA387 GR.5 CL.1 | Thickness mm | Yield Min Mpa | Tensile Mpa | Elongation Min % |
| t≦50 | 205 | 415-585 | 18 | |
| 50 | - | - | - | |
Tensile Requirements for ASME SA387 Grade 5 Alloy Steel Plates Class 1 Plates
| Designation: | Requirement: | Grade 5 |
|
SA387 Grade 5 |
Tensile strength, ksi [MPA] | 75 to 100 [515 to 690] |
| Yield strength, min, ksi [MPa]/(0.2% offset) | 45 [310] | |
| Elongation in 8 in. [200mm], min % | ... | |
| Elongation in 2 in. [50mm], min, % | 18 | |
| Reduction of area, min % | 45 (measured on round specimen) 40 (measured on flat specimen) |
Key Characteristics & Processing
Material: A chrome-moly alloy steel designed for elevated temperatures, offering better corrosion resistance than carbon steels, notes www.steelplateindia.com and steelpipesuppliers.com.
Applications: Ideal for welded boilers, heat exchangers, and pressure vessels in petrochemical, chemical, and power industries, says www.steelplateindia.com, steelpipesuppliers.com, and gailsteelengg.in.
Heat Treatment: Requires normalization and tempering to achieve optimal mechanical properties, toughness, and stability, according to Amardeep Steel Centre and gailsteelengg.in.
Mechanical Properties: Offers a good balance of strength, toughness, and high-temperature creep resistance, explains www.steelplateindia.com and gailsteelengg.in.
Fabrication: Features good weldability, making it suitable for various fabrication processes, notes steelpipesuppliers.com.
Processing Steps & Considerations
Sourcing: Procured as plates from manufacturers, often with mill test reports (MTRs).
Cutting & Forming: Plates are cut and prepared (e.g., beveled) for welding.
Heat Treatment: Typically normalized and tempered by the mill or fabricator to meet ASME SA 387 standards.
Welding: Requires specific welding procedures to maintain material integrity, often involving pre-heating and post-weld heat treatment.
Testing: Subjected to tension, impact, and non-destructive tests (NDT) to ensure compliance, as detailed in gailsteelengg.in.
Certification: Comes with documentation verifying compliance with ASME standards.
Key Applications:
Oil & Gas Industry: Pressure vessels, storage tanks, and pipelines in offshore drilling and refining.
Petrochemical & Chemical Plants: Reactors, heat exchangers, and process equipment.
Power Generation: Boilers, steam generators, and components in thermal power plants.
General Industrial: Heat exchangers, condensers, and machinery requiring high strength at elevated temperatures.
Why it's Used
High-Temperature Strength: Molybdenum addition enhances tensile strength at high temperatures.
Corrosion Resistance: Chromium provides better resistance to atmospheric corrosion and high-temperature environments.
Weldability: Good weldability, allowing for complex fabrication.
Durability: Resistant to embrittlement during thermal cycling, ensuring a longer service life.
Request a professional quotation for SA 387 Grade 5 Class 1 from GNEE Steel.
What type of steel is SA 387 GRADE 5 Class 1?
It is a chromium-molybdenum alloy heat-resistant steel complying with ASTM standards, featuring good high-temperature strength and creep resistance, mainly used for pressure equipment in medium-high temperature conditions.
What are the core alloying elements and their content ranges of this steel?
The core elements are chromium (2.00%-2.50%) and molybdenum (0.90%-1.10%), supplemented by carbon, manganese, etc. The alloy ratio optimizes its high-temperature mechanical properties and corrosion resistance.
What is the approximate maximum operating temperature it can withstand?
The maximum operating temperature is about 593℃. It maintains stable mechanical properties in this range, hardly undergoes creep deformation, suitable for medium-high temperature pressure scenarios.
In which industrial fields is this material mainly used?
It is widely used in petrochemical, power, boiler manufacturing industries, often for reactors, heat exchangers, steam pipes and high-temperature pressure vessel components.
What is the usual delivery condition of SA 387 GRADE 5 Class 1?
The delivery condition is mostly normalizing plus tempering. Normalizing improves structural uniformity, tempering eliminates internal stress, ensuring stable hardness, strength and toughness ratio.
What is the standard tensile strength range of this steel?
The standard tensile strength ranges from 485MPa to 655MPa, with yield strength not less than 275MPa, meeting structural strength requirements of pressure equipment in medium-high temperature conditions.
What is the core difference between it and SA 387 GRADE 5 Class 2?
The main difference lies in tempering temperature and impact performance. Class 1 has higher tempering temperature and slightly lower impact toughness, while Class 2 suits low-temperature impact scenarios.
Can this material resist acidic medium corrosion?
It has certain corrosion resistance to weak acidic media due to the passivation film formed by chromium and molybdenum, but additional anti-corrosion treatment is needed in strong corrosion conditions to avoid damage.
What is the microstructure of SA 387 GRADE 5 Class 1 after heat treatment?
After normalizing and tempering, its microstructure is tempered bainite or ferrite, which endows the steel with excellent comprehensive mechanical properties and high-temperature stability.
Is this steel weldable? What precautions should be taken during welding?
It is weldable, but preheating (150-250℃) and post-weld heat treatment are required to prevent cold cracks and reduce residual stress, ensuring welding joint quality.