What factors influence the price of SA387 Grade 5 Class 2?
SA387 Grade 5 Class 2 is a chrome-molybdenum alloy steel plate (ASME SA387/ASTM A387) designed for high-temperature, high-pressure applications like boilers and pressure vessels, offering excellent strength and corrosion resistance due to its chromium (Cr) and molybdenum (Mo) content, with Class 2 indicating specific tensile strength properties. It's a weldable steel, ideal for industries needing robust material for extreme conditions, with key elements including ~4-6% Chromium and ~0.4-0.7% Molybdenum, plus strict limits on Carbon, Manganese, Phosphorus, and Sulfur.The price of SA387 Grade 5 Class 2 is driven by its status as a specialty high-alloy steel supplied in a normalized and tempered (N+T) condition.
1. Primary Cost Drivers: Alloy & Production
High Alloy Surcharge: The ~5% Chromium content is the dominant cost factor. Prices track volatile chromium and molybdenum markets closely. This grade incurs a significantly higher alloy premium than low-Cr steels (e.g., Grades 11, 12, 22).
Specialty Mill Production: Only a limited number of mills worldwide produce quality 5Cr-0.5Mo plate. This limited competition and niche production lead to higher base pricing and less price transparency.
Stringent Heat Treatment (Class 2): The normalizing and tempering process is more energy-intensive and technically demanding than annealing, adding substantial processing cost. Precise temperature control and cooling rates are critical.
2. Product Specifications
Plate Dimensions: Thickness is a major multiplier. Thick plates (>75mm) require specialized rolling and extended heat treatment, consuming more alloy and furnace time. Non-standard widths also increase cost.
Quantity: Orders are typically small-volume (e.g., single plates for repair or specific vessel sections), eliminating economies of scale. Mill minimum order quantities (MOQs) may still apply.
Certification & Testing: Beyond standard MTRs, rigorous testing is common and costly-including impact testing at specific temperatures, ultrasonic testing (UT), and often Hydrogen-Induced Cracking (HIC) or Sulfide Stress Cracking (SSC) tests per NACE MR0175/ISO 15156 for refinery service.
3. Market & Supply Chain Factors
Demand Source: Demand is tied to high-value refinery projects-such as hydrocrackers, hydrogen reformers, and catalytic reactors-where high-temperature corrosion resistance (≥600°C) is critical. Refinery turnaround cycles can create sudden demand spikes.
Supply Constraints: Long lead times (often 12-20 weeks) are typical due to made-to-order production. Urgent/ex-stock delivery commands a very high premium.
Trade & Logistics: As a strategic material, it may be affected by export controls or tariffs. Freight costs for heavy, thick plates are significant.
4. Quality & Compliance Premium
Mill Reputation: Plates from premium mills (e.g., European, Japanese, or specialized US mills) with proven performance in hydrogen service justify a higher price due to reliability and traceability.
Certifications: Compliance with ASME Section II, NACE, and possibly PED (CE marking) involves additional documentation and quality assurance steps that add cost.
Comparison with Other Grades
| Factor | SA387 Gr 5 Cl 2 vs. Gr 22 Cl 2 | SA387 Gr 5 Cl 2 vs. Gr 5 Cl 1 |
|---|---|---|
| Alloy Cost | Higher (5% Cr vs. 2.25% Cr). | Similar alloy cost, but Class 2 N&T adds more processing cost than Class 1 annealing. |
| Application | Used in more corrosive/oxidizing environments; niche demand. | Class 2 has higher as-supplied strength, often avoiding final full heat treatment. |
Summary: Key Price Influencers for SA387 Gr 5 Cl 2
Alloy surcharge (especially chromium price).
Plate thickness and non-standard dimensions.
Low order volumes (lack of scale economies).
Stringent N+T heat treatment.
Advanced testing requirements (impact, HIC, UT).
Mill reputation and certification complexity.
Long lead times vs. urgent delivery needs.
Procurement Strategy
Plan Early: Engage suppliers 6–12 months ahead to secure mill capacity.
Bundle Requirements: If possible, consolidate projects to increase order volume.
Specify Precisely: Define all testing/certification needs upfront to avoid change orders.
Consider Total Cost: While Class 2 has a higher upfront cost than Class 1, it may reduce total cost by minimizing post-fabrication heat treatment.
In essence, SA387 Grade 5 Class 2 is a premium, application-specific material where cost is driven by alloy content, specialized production, and rigorous quality demands rather than commodity steel markets.
1.What is SA387 Grade 5 Class 2?
Answer: SA387 Grade 5 Class 2 is a chromium-molybdenum alloy steel plate specification for pressure vessels, specifically supplied in the normalized and tempered heat treatment condition for improved properties.
2.What is the chemical composition of SA387 Gr5 Cl 2?
Answer: Its composition includes Chromium (4.00-6.00%), Molybdenum (0.45-0.65%), with maximum limits for Carbon (0.15%), Manganese (0.30-0.60%), Silicon (0.50%), Phosphorus, and Sulfur.
3.How does SA387 Grade 5 Class 2 differ from Class 1?
Answer: The key difference is mandatory heat treatment. Grade 5 Class 2 must be supplied in the normalized and tempered condition, ensuring a specific microstructure and consistent mechanical properties, while Class 1 has more flexible heat treatment options.
4.What are the mechanical properties of SA387 Grade 5 Class 2?
Answer: It has a minimum tensile strength of 515-690 MPa (75-100 ksi) and a minimum yield strength of 310 MPa (45 ksi). The normalized and tempered condition generally provides better toughness.
5.What is SA387 Grade 5 Class 2 used for?
Answer: It is primarily used in high-temperature hydrogen service in petroleum refineries, such as in hydroprocessing reactors, hydrocrackers, and other pressure vessels exposed to sulfidic corrosion.
6.What is the required heat treatment for SA387 Gr5 Cl 2 material?
Answer: According to the specification, SA387 Grade 5 Class 2 plates must be normalized (heated to a suitable temperature above the transformation range) and then tempered (reheated to a specific temperature below the transformation range).
7.What is the post-weld heat treatment (PWHT) for SA387 Grade 5 Class 2?
Answer: Welded fabrications almost always require PWHT, typically performed in the temperature range of 1250-1350°F (677-732°C), to relieve stresses and temper the heat-affected zone.
8.What filler metal is used to weld SA387 Grade 5 Class 2?
Answer: Welding typically uses AWS E502-XX or E505-XX class electrodes (e.g., E502-16) for matching composition, with strict control of preheat (often 300-400°F / 149-204°C) and interpass temperature.
9.What is the maximum service temperature for SA387 Grade 5 Class 2?
Answer: It is commonly used for continuous service at metal temperatures up to approximately 1200°F (649°C) in refinery environments involving hydrogen and sulfur.
10.Why is SA387 Grade 5 Class 2 preferred for certain vessels?
Answer: Class 2 is preferred when the design requires guaranteed, consistent mechanical properties and enhanced toughness from the normalized and tempered microstructure, especially for critical, thick-section pressure vessels.
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.
