ASTM A387 Grade 11 is a chromium-molybdenum alloy steel plate specifically engineered for use in welded boilers and pressure vessels intended for elevated temperature service. Its composition, typically including 1.00-1.50% chromium and 0.45-0.65% molybdenum, provides excellent resistance to high temperatures and corrosion, making it a preferred material in the petrochemical, oil and gas, and power generation industries.
Key Characteristics of ASTM A387 Grade 11 Plates
- High-Temperature Strength: Maintains mechanical integrity at elevated temperatures.
- Corrosion Resistance: Offers good resistance to oxidation and sulfidation in its designated service environments.
- Weldability: Can be readily welded using standard procedures, though preheating and post-weld heat treatment (PWHT) are often recommended or required depending on thickness and application code.
- Notch Toughness: Exhibits good toughness, which is particularly important for pressure equipment integrity.
Selecting ASTM A387 Grade 11 Manufacturers
Choosing a reliable manufacturer is crucial for ensuring the quality and performance of ASTM A387 Grade 11 alloy steel plates. Key factors to consider include:
- Compliance with ASTM Standards: The manufacturer must strictly adhere to the ASTM A387/A387M specification. This includes precise control over chemical composition, ensuring mechanical properties (tensile strength, yield strength, elongation) meet the specified Class, and performing correct heat treatment procedures.
- Quality Management Systems: Look for certifications like ISO 9001, which indicate robust quality control processes are implemented throughout the manufacturing cycle.
- Mill Test Certificates (MTCs): Reputable manufacturers provide comprehensive MTCs, typically to EN 10204 3.1 (or 3.2 if third-party inspection is specified), detailing the chemical analysis and mechanical test results for each plate or heat.
- Production Capabilities and Range: Assess the manufacturer’s capacity for producing the required plate dimensions (thickness, width, length) and quantities. Some specialized suppliers, like Shanxi Luokaiwei Steel Company, often highlight their ability to meet diverse customer specifications and project requirements.
- Experience and Industry Reputation: An established track record in supplying materials for critical applications and positive industry feedback are good indicators of reliability and product quality.
- Testing Facilities: In-house or accredited third-party testing capabilities for supplementary requirements such as ultrasonic testing (UT), Charpy V-notch impact testing, and hydrogen-induced cracking (HIC) tests, if applicable.
Several global steel mills and specialized plate producers manufacture ASTM A387 Grade 11 plates. While specific sourcing decisions will depend on project location, detailed technical specifications, and commercial terms, it is advisable to engage with manufacturers who can demonstrate a consistent supply of high-quality, fully certified material. Well-known international mills often have extensive experience with this grade. Regional suppliers, such as Shanxi Luokaiwei Steel Company, also play a significant role in the supply chain, often focusing on specific market needs. Thorough vetting of any potential supplier, including perhaps Shanxi Luokaiwei Steel Company, is always recommended through audits or reference checks.
Important Considerations When Ordering
- Specify Class: ASTM A387 Grade 11 is available in two classes: Class 1 (typically annealed) and Class 2 (typically normalized and tempered). Class 2 offers higher tensile and yield strength. The required class must be clearly specified.
- Supplementary Requirements: The ASTM A20/A20M specification (General Requirements for Steel Plates for Pressure Vessels) lists numerous supplementary requirements (e.g., S1 Vacuum Treatment, S2 Product Analysis, S3 Simulated Post-Weld Heat Treatment Mechanical Test Coupons, S5 Charpy V-Notch Impact Test, S8 Ultrasonic Examination). Specify any that are necessary for the application.
- Surface Condition and Dimensional Tolerances: Define acceptable surface finishes and ensure adherence to dimensional tolerances as per ASTM A20/A20M or other agreed-upon standards.
Engaging with experienced manufacturers and suppliers, potentially including entities like Shanxi Luokaiwei Steel Company, can help ensure that the ASTM A387 Grade 11 plates meet all necessary technical and quality criteria for demanding high-temperature, high-pressure applications. Always meticulously review Mill Test Certificates and any other specified documentation before accepting materials to confirm full compliance.
