What is ASME SA387 Grade 11 Class 1 Low Alloy Steel Plate?
ASME SA‑387 Grade 11 Class 1 is a 1.25Cr‑0.5Mo low‑alloy chromium‑molybdenum heat‑resistant steel plate conforming to ASME SA‑387 / SA‑387M (equivalent to ASTM A387). Class 1 denotes the normalised delivery condition, and this grade is engineered for medium‑temperature pressure‑containing equipment. Thanks to its balanced high‑temperature creep resistance, good sulphidation corrosion resistance and favourable weldability, this grade stands as the preferred material for heat exchangers operating under worldwide high‑temperature and high‑pressure service conditions. For global heat‑exchanger manufacturers, EPC contractors and pressure‑vessel fabricators, SA‑387 Gr 11 Cl 1 delivers an optimal balance between performance and total cost of ownership.
With more than 18 years of export experience in pressure‑vessel and heat‑resistant alloy steel plates, GNEE Steel supplies ASME‑compliant SA‑387 Gr 11 Class 1 plates to petrochemical, power‑generation and refinery clients across the Middle East, Southeast Asia, Europe and Latin America. We strictly adhere to ASME code requirements, source materials from qualified domestic steel mills, and implement full‑process traceability management. Each consignment can be supplied with mill Material Test Certificates (MTC) complying with EN 10204 3.1, or third‑party validated 3.2 certificates. Our in‑house technical team can provide material‑selection advice, welding guidance and technical‑specification review services for heat‑exchanger projects.
Please submit your heat‑exchanger service‑condition parameters (operating temperature, process media, required plate thickness). Our metallurgical engineers will deliver a free material‑selection proposal within 24 working hours.
ASME SA387 Grade 11 Class 1 Low Alloy Steel Plate For Heat Exchanger Specification
| Item | Specification |
|---|---|
| Product Name | ASME SA387 Grade 11 Class 1 Low Alloy Steel Plate For Heat Exchanger |
| Standard | ASTM A387 / ASME SA387 |
| Thickness Range | 5 mm – 150 mm |
| Width Range | 1,000 mm – 4,500 mm |
| Length Range | 3,000 mm – 18,000 mm |
ASME SA387 Grade 11 Class 1 Low Alloy Steel Plate Chemical Composition
| Element | Heat Analysis | Product Analysis |
|---|---|---|
| C | 0.05‑0.17 | 0.04‑0.17 |
| Mn | 0.40‑0.65 | 0.35‑0.73 |
| Si | 0.50‑0.80 | 0.44‑0.86 |
| Cr | 1.00‑1.50 | 0.94‑1.56 |
| Mo | 0.45‑0.65 | 0.40‑0.70 |
| P | ≤0.035 | ≤0.035 |
| S | ≤0.035 | ≤0.035 |
ASME SA387 Grade 11 Class 1 Low Alloy Steel Plate Mechanical Property
| Item | Required Value |
|---|---|
| Tensile Strength | 415‑585 MPa (60‑85 ksi) |
| Minimum Yield Strength (0.2% offset) | 240 MPa (35 ksi) |
| Elongation (50 mm gauge length) | ≥22 % |
| Elongation (200 mm gauge length) | ≥19 % |
| Minimum Tempering Temperature | 620 °C (1150 °F) |
| Maximum design temperature (ASME VIII‑1) | 649 °C |
| Maximum design temperature (ASME VIII‑2) | 482 °C |
Key Advantages of ASME SA‑387 Gr11 Class 1 Plate for Heat‑Exchanger
1. Excellent High‑Temperature Creep‑Resistant Performance
Molybdenum (Mo) enhances the long‑term creep‑rupture strength of the material under sustained high‑temperature service conditions ranging from 400 °C to 600 °C. It effectively prevents bulging or permanent deformation of shells and tube sheets under thermal‑cycling conditions, which is critical for guaranteeing long‑term operational reliability of heat exchangers.
2. Good Oxidation Resistance and Compatibility with Acidic Process Media
Chromium (Cr) forms a dense protective oxide layer on the steel surface. The material resists oxidation at moderate temperatures and offers good tolerance to hydrogen‑sulphide‑containing (H₂S) process media found in refinery heat exchangers, lowering the risk of sulphidation‑corrosion damage.
3. Favourable Weldability
Controlled carbon equivalent delivers moderately stringent preheat requirements for welding. A high first‑pass weld acceptance rate can be achieved during tube‑sheet butt welding and shell longitudinal seam welding, reducing on‑site rework and cutting manufacturing costs for heat‑exchanger fabricators.
4. Stable Impact Toughness Under Thermal‑Cycle Service
Heat exchangers frequently undergo temperature fluctuations during start‑up and shut‑down cycles. This grade exhibits acceptable Charpy impact properties to mitigate brittle‑fracture risks in welds and base metal subjected to alternating thermal loads. GNEE can supply batches with 100 % impact testing performed upon project‑specific request.
5. Optimised Total Procurement and Fabrication Costs
Compared with higher‑alloy grades such as Gr22 or stainless steel, SA‑387 Gr11 Cl1 delivers reduced material expenditure. Furthermore, it eliminates the need for complex post‑weld heat treatment (PWHT), further lowering overall manufacturing costs for heat‑exchanger OEMs.
Request sample sets of complete Material Test Certificates (MTC) containing actual measured chemical composition and mechanical‑property data for verification against your project technical specifications.
ASME SA387 Grade 11 Class 1 Application Scenarios in Heat‑Exchanger Industry
- Shell‑and‑tube heat exchangers: Shell plates, tube sheet blanks for refinery, petrochemical and chemical process heat transfer units;
- Waste‑heat recovery heat exchangers: Plates for flue‑gas waste‑heat recovery devices in thermal power plant and process plants;
- High‑temperature plate‑type heat‑exchanger modules: Medium‑temperature pressure‑bearing plate components for chemical synthesis loops;
- Auxiliary pressure parts matched with heat‑exchanger system: buffer drums, separator shells connected to heat‑exchanger loops;
- Power‑plant heat‑exchange equipment: component plates for economiser and intermediate heat‑exchange assemblies;
- Downstream industries: oil & gas refineries, thermal power stations, fine chemical plants, pulp & paper industry, pharmaceutical chemical processing.
Why Choose GNEE Steel?
- Custom processing service: Plasma cutting, flame cutting, laser cutting, edge beveling, blasting & anti‑rust surface treatment for heat‑exchanger tube‑sheet blanks and shell segments.
- Custom inspection items: Standard chemical, tensile, impact test; optional UT ultrasonic testing, HIC test for sour service, NACE MR0175 compliance, Z‑direction property (Z15/Z25/Z35), PMI positive material identification.
- Export‑oriented packaging: Waterproof anti‑rust paper, steel band fastening, fumigated wooden pallets for ocean shipment to avoid rusting and mechanical damage during long‑distance sea transport.
FAQ
What is the maximum allowable operating temperature for SA387 Gr11 Class 1 heat exchanger?
The maximum allowable continuous operating temperature for an ASME SA387 Grade 11 Class 1 heat exchanger is typically 540°C (1004°F), with code-sanctioned property data and allowable stress values extending up to 550°C (1002°F) in ASME Section II Part D. Operating above 500°C enters the time-dependent creep deformation regime for this 1.25Cr-0.5Mo low-alloy steel.
What is the difference between Class 1 and Class 2 of SA387 Gr11? Can I replace each other directly?
The main difference between Class 1 and Class 2 of ASME SA387 Grade 11 is their mechanical strength and heat treatment, even though they share the exact same chemical composition (1.25% Chromium and 0.5% Molybdenum). Class 2 provides higher yield and tensile strength, while Class 1 offers higher elongation and better ductility. No, you cannot replace them directly without a proper engineering re-evaluation.
What equivalent steel grades can substitute SA387 Gr11 Class 1?
Equivalent international standards for ASME SA387 Grade 11 Class 1 (a 1.25% Cr – 0.5% Mo chrome-moly pressure vessel steel plate) include the EN European standard 13CrMoSi5-5, British Standard BS 621B, and ASTM counterpart [ASTM A387 Grade 11 Class 1](0.6.8, 0.6.10).
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