SA 387 Grade 5 Class 1 is a chromium-molybdenum alloy steel plate under the ASME Boiler and Pressure Vessel Code, intended for welded pressure vessels and boiler parts operating at high temperatures. It offers good high-temperature strength, creep resistance, toughness, and weldability. The Class 1 designation reflects specific mechanical properties and heat treatment, usually normalizing and tempering, to balance strength and ductility. It is widely used in refineries, petrochemical plants, and power generation systems where reliable performance under thermal stress is required.
Equivalents
| BS | EN | ASME | DIN |
| ... | ... | SA387-5-1 | ... |
Specifications ASME SA387 Grade 5 Alloy Steel Plates
| Designation | Nominal Chromium Content (%) |
Nominal Molybdenum Content (%) |
| SA387 Grade 5 | 5.00% | 0.50% |
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) |
Chemical Requirements for ASME SA387 Grade 5 Alloy Steel Plates
| Element | Chemical Composition (%) | |
| SA 387 Grade 5 | ||
| Carbon: | Heat Analysis: | 0.15 max |
| Product Analysis: | 0.15 max | |
| Manganese: | Heat Analysis: | 0.30 - 0.60 |
| Product Analysis: | 0.25 - 0.66 | |
| Phosphorus: | Heat Analysis: | 0.035 |
| Product Analysis: | 0.035 | |
| Sulphur (max): | Heat Analysis: | 0.030 |
| Product Analysis: | 0.030 | |
| Silicon: | Heat Analysis: | 0.50 max |
| Product Analysis: | 0.55 max | |
| Chromium: | Heat Analysis: | 4.00 - 6.00 |
| Product Analysis: | 3.90 - 6.10 | |
| Molybdenum: | Heat Analysis: | 0.45 - 0.65 |
| Product Analysis: | 0.40 - 0.70 |
Key Features:
Material: Chromium-Molybdenum (Cr-Mo) Alloy Steel.
Application: Designed for welded boilers and pressure vessels operating at elevated temperatures.
High-Temperature Strength: Molybdenum content significantly increases tensile strength at high temperatures.
Corrosion Resistance: Chromium provides improved resistance to oxidation and various corrosive media, including some acids and chloride stress cracking.
Toughness: Offers good toughness and resistance to thermal cycling embrittlement.
Weldability: Suitable for welding, though post-weld heat treatment (PWHT) is often required.
Heat Treatment: Typically supplied normalized and tempered to achieve desired mechanical properties.
Primary Applications
Pressure Vessels: The material is a standard choice for fabricating pressure vessels designed to safely store or process fluids at extremely high temperatures and pressures, a necessity in the oil, gas, and chemical industries.
Boilers: It is widely used in power generation facilities for components in industrial boilers and steam generation systems that operate continuously under high thermal stress.
Heat Exchangers and Reactors: In petrochemical processing plants and refineries, these plates form essential equipment like heat exchangers and reactor vessels, where they facilitate efficient heat transfer or chemical reactions without succumbing to thermal degradation or corrosion.
Industrial Settings: The material's reliability makes it a staple in various heavy industrial sectors, including general chemical processing plants and oil refineries, for critical infrastructure and piping systems.
Why it's Used
High-Temperature Service: The added molybdenum concentration significantly enhances the material's tensile strength and creep resistance at elevated temperatures, allowing it to maintain structural integrity where standard carbon steel would fail.
Corrosion Resistance: The substantial chromium content provides excellent resistance to oxidation, scaling, and various corrosive agents (e.g., in "sour service" environments), extending the lifespan of equipment and reducing maintenance costs.
Weldability: Despite its high performance characteristics, SA 387 Grade 5 Class 1 offers good weldability, allowing fabricators to construct complex and large-scale components using conventional welding methods without compromising the material's inherent properties, particularly with proper pre- and post-weld heat treatments. This makes fabrication into custom equipment easier and more efficient.
Full specification and details are available on request. The above information is provided for guidance purposes only. For specific design requirements please contact our technical sales staff.
What is the melting point range of SA 387 GRADE 5 Class 1?
Its melting point range is about 1450-1500℃, which is slightly lower than carbon steel due to alloy elements, but it still has good high-temperature stability below the melting point.
What is the application limit of SA 387 GRADE 5 Class 1 in terms of pressure?
It is suitable for medium-high pressure environments, usually with a working pressure of up to 10-30MPa, specific limits depending on temperature, structural design and service conditions.
What is the thermal conductivity of SA 387 GRADE 5 Class 1 and how does it affect application?
Its thermal conductivity is about 40-45 W/(m·K) at room temperature, which is lower than carbon steel, requiring reasonable design in heat exchange equipment to ensure heat transfer efficiency.
What post-weld heat treatment methods are suitable for SA 387 GRADE 5 Class 1?
Suitable post-weld heat treatment methods include tempering and stress relief annealing, which can eliminate welding residual stress, improve joint toughness and prevent stress corrosion cracking.
What is the difference between SA 387 GRADE 5 Class 1 and carbon steel in terms of high-temperature performance?
Compared with carbon steel, it has better high-temperature strength and creep resistance, not easy to oxidize and soften at high temperatures, suitable for more harsh high-temperature conditions.
How to detect the quality of SA 387 GRADE 5 Class 1 after processing?
Common detection methods include ultrasonic testing, magnetic particle testing, chemical composition analysis and mechanical property testing to ensure no defects and meet standard requirements.
What is the carbon content range of SA 387 GRADE 5 Class 1 and its function?
Carbon content ranges from 0.15% to 0.25%. It improves the strength and hardness of the steel, but excessive carbon will reduce its toughness and weldability.
What are the main defects to avoid in the production process of SA 387 GRADE 5 Class 1?
Main defects to avoid include segregation, porosity, cracks and inclusions. Strict control of smelting and heat treatment processes can effectively reduce these defects.
How to store SA 387 GRADE 5 Class 1 steel plates to prevent corrosion?
Store in a dry, well-ventilated warehouse, avoid contact with moisture and corrosive media, and cover with waterproof and anti-corrosion materials to prevent surface rusting.
What is the development trend of SA 387 GRADE 5 Class 1 in industrial applications?
With the upgrading of petrochemical and power industries, it is developing towards higher purity and more precise alloy ratio to meet more harsh high-temperature and high-pressure requirements.