ASME SA387 Gr.5 alloy steel plates are chromium-molybdenum alloy pressure vessel steels manufactured in accordance with the ASME Boiler and Pressure Vessel Code (BPVC). Containing approximately 5% chromium and 0.5% molybdenum, this alloy is engineered to provide excellent high-temperature strength, oxidation resistance, and long-term creep resistance. To meet diverse pressure vessel design requirements, these plates are typically supplied in either Class 1 or Class 2 heat-treated condition.
As a seasoned manufacturer of pressure vessel steel plates, GNEE Steel supplies SA387 Gr.5 plates in thicknesses ranging from 6 to 300 mm, offering ultrasonic testing (UT), EN 10204 3.1/3.2 certification, and custom fabrication services.
ASME SA387 Gr.5 alloy steel plate Specification
| Item | Specification |
|---|---|
| Product Standard | ASME SA387 / ASTM A387 |
| Grade | SA387 Grade 5 / ASTM A387 Grade 5 |
| Class | Class 1, Class 2 |
| Steel Type | Chromium-Molybdenum Alloy Pressure Vessel Steel |
| Chromium Content | Approximately 4.00–6.00% |
| Molybdenum Content | Approximately 0.45–0.65% |
| Thickness | 6–300 mm |
| Width | 1,500–4,000 mm |
| Length | 3,000–18,000 mm |
| Plate Shape | As Rolled, Cut-to-Size |
| Delivery Condition | Normalized (Class 1); Normalized & Tempered (Class 2)* |
ASME SA387 Gr.5 alloy steel plate Chemical Composition
| C | Mn | P | S | Si | Cr | Mo |
| 0.15 max | 0.25 - 0.66 | 0.035 | 0.030 | 0.55 max | 3.9 - 6.1 | 0.40 - 0.7 |
ASME SA387 Gr.5 alloy steel plate Mechanical Property
| A387 / SA387 Grade 5 | Class 1 | Class 2 |
| Tensile Strength (ksi) | 60-85 | 75-100 |
| Tensile Strength (MPa) | 415-585 | 515-690 |
| Yield Strength (ksi) | 30 | 45 |
| Yield Strength (MPa) | 205 | 310 |
| Elongation in 50mm (%) | 18 | 18 |
| Reduction of area in % | 45 | 45 |
High-Temperature Performance of ASME SA387 Gr.5 Alloy Steel Plates
1. Excellent Long-Term Creep Resistance
The addition of chromium (Cr) and molybdenum (Mo) enhances carbide stability and strengthens the steel matrix. This enables SA387 Gr.5 to sustain long-term service at temperatures up to approximately 600°C (1112°F) while minimizing creep deformation.
Key Benefits:
Exceptional creep-rupture strength during long-term service.
Superior dimensional stability under sustained loads.
Extended service life for pressure vessels and reactors.
2. Outstanding High-Temperature Oxidation Resistance
Containing 4.00% to 6.00% chromium, SA387 Gr.5 forms a dense, protective chromium oxide scale. This minimizes oxidation and scaling in continuous operating environments ranging from 500 to 600°C.
Key Benefits:
Outstanding resistance to oxidation and scaling.
Reduced material degradation at elevated temperatures.
Lower maintenance and inspection costs.
3. Reliable Thermal Fatigue Resistance
Pressure equipment frequently undergoes cyclic start-ups, shutdowns, and temperature fluctuations. Following proper normalizing or normalizing and tempering (N&T), our SA387 Gr.5 develops a refined microstructure that effectively resists thermal fatigue cracking and maintains structural integrity during cyclic service.
Key Benefits:
Excellent resistance to cyclic thermal stress.
Enhanced crack resistance during temperature fluctuations.
Stable performance during long-term operation in refineries and power plants.
Looking for plates for reactors, reformers or fired heaters? Our engineering team can recommend the most suitable SA387 grade based on your operating temperature and design pressure.
Heat Treatment of ASME SA387 Gr. 5 Alloy Steel Plates
Proper heat treatment is critical to achieving the elevated-temperature mechanical properties required for pressure vessel applications. Our ASME SA387 Gr. 5 steel plates are available in various heat-treated conditions to meet diverse design and service requirements.
class 1
Class 1 – Normalized (N)
Our Class 1 plates are typically supplied in the normalized condition. The normalizing process refines the grain structure, improves microstructural uniformity, and provides stable strength and ductility for general high-temperature pressure vessel applications.
Key Features:
Refined grain structure.
Uniform mechanical properties.
Good weldability and formability.
class 2
Class 2 – Normalized and Tempered (NT)
Our Class 2 plates undergo normalizing followed by tempering to develop a tempered bainite or tempered martensite microstructure, significantly enhancing toughness and long-term creep resistance. This condition is typically specified for more demanding pressure vessels operating under high temperatures and cyclic thermal loads.
Key Features:
Improved toughness and ductility.
Enhanced creep resistance for long-term service.
Superior resistance to thermal fatigue and stress cracking.
Welding Considerations
- Preheat: For plates thicker than ~12 mm, preheating at 150–200°C is recommended to prevent hydrogen-induced cracking (HIC).
- Post-Weld Heat Treatment (PWHT): PWHT at 620–680°C is typically required for welded assemblies, especially for thick-wall vessels. This relieves residual stresses and tempers the weld heat-affected zone (HAZ).
- Simulated PWHT (SPWHT): For critical applications, GNEE Steel can supply plates that have undergone simulated PWHT, allowing mechanical property testing on material in its post-service condition.
Typical Applications of ASME SA387 Gr. 5 Alloy Steel Plates
Oil Refining & Petrochemical
- Catalytic cracking units - reactor and regenerator shells
- Hydroprocessing reactors - hydrodesulfurization (HDS), hydrocracking vessels
- Sulfur recovery units - Claus reactor vessels and tail gas treatment
- High-temperature heat exchangers and separators handling sour service fluids
- Distillation column internals and tower shells in crude units
Power Generation
- Boiler drums and steam separators
- Heat Recovery Steam Generators (HRSG) components
- Superheater and reheater headers
- High-pressure piping and manifolds
Chemical Processing
- Reactors handling hydrogen-rich streams at elevated temperature
- High-temperature storage tanks for corrosive media
- LPG storage spheres and pressure vessels
GNEE Steel - Your Pressure Vessel Plate Partner
With over 18 years of specialization in steel plate supply, GNEE Steel has established itself as a trusted source for chromium-molybdenum alloy plates, including the full range of ASME SA387 grades. Our pressure vessel plate inventory and processing capabilities are built to serve fabricators, EPC contractors, and end-users across the global energy and petrochemical sectors.
Years of steel experience
Countries Served
Global partners
Professional Team
What We Offer for SA387 Gr.5?
- Full Dimensional Range: Thickness 6 mm – 300 mm | Width up to 4,000 mm | Length up to 18,000 mm
- Both Classes Available: Class 1 (N) and Class 2 (N+T) to meet your design code requirements
- Mill Test Certificates: EN 10204 Type 3.1 / 3.2 MTC provided with every order, including full heat analysis and mechanical test data
- Third-Party Inspection: We support on-site inspection by BV, SGS, TÜV, and other recognized agencies
- Simulated PWHT Service: Plates can be supplied with simulated post-weld heat treatment for critical applications, with mechanical properties tested in the post-PWHT condition
- Flexible Ordering: MOQ from 1 piece; in-stock items ship immediately, production orders typically complete in 10–40 days
- Deep Processing: Cutting to size, beveling, surface treatment (shot blasting, painting) available per customer requirements
Quality Assurance
Every plate we supply undergoes a rigorous quality control process: heat analysis verification, mechanical property testing (tensile, yield, elongation, hardness), ultrasonic testing per ASTM A435/A578, and full documentation with heat number traceability. Our procurement and QC teams verify compliance with ASME SA-387/SA-387M requirements before any material is released for shipment.
FAQ
Q: How does SA387 Gr.5 compare to Gr.11 (1.25Cr-0.5Mo) in terms of corrosion resistance and strength?
A: SA387 Gr. 5 (5.00%Cr-0.50%Mo) significantly outperforms Gr. 11 (1.25%Cr-0.50%Mo) in corrosion resistance and high-temperature strength. Its higher chromium content provides superior oxidation and scaling resistance at higher temperatures, while both grades use molybdenum to resist high-temperature creep.
Q: What is the difference between Gr.5 and Gr.22 (2.25Cr-1Mo)?
A: Gr.5 (5Cr-0.5Mo) and Gr.22 (2.25Cr-1Mo) are both high-performance, low-alloy chromium-molybdenum steels. Their primary difference lies in their chemical composition, which dictates their specific temperature limits, corrosion resistance, and suitability for different industrial applications.
Q: How does Gr.5 compare to Gr.9 (9Cr-1Mo)?
A: ASTM Grade 5 (5Cr-0.5Mo) and Grade 9 (9Cr-1Mo) are both high-temperature, corrosion-resistant ferritic alloy (chrome-moly) steels. Grade 9 contains roughly double the chromium and twice the molybdenum of Grade 5, which gives it superior high-temperature strength, creep resistance, and corrosion defense.
Q: What distinguishes Gr.5 from Gr.12 (1Cr-0.5Mo)?
A: Gr.5 and Gr.12 (1Cr-0.5Mo) are both high-temperature, chromium-molybdenum alloy steels, but Gr.5 contains significantly more chromium and can withstand much higher operating temperatures and corrosive environments.
Q: What are the differences between SA387 Gr.5, Gr.9 and Gr.11?
A: ASME SA387 Grades 5, 9, and 11 are chromium-molybdenum (Chrome-Moly) alloy steel plates used in elevated temperature and pressure vessels. The primary differences lie in their chromium and molybdenum content, which dictates their corrosion resistance, temperature tolerance, and specific industrial applications.
