347 Stainless Steel Pipe Description
Main Characteristics:
- Contains tantalum and niobium for improved resistance to intergranular corrosion.
- Maintains high strength while preserving ductility, allowing for reduced material thickness.
- Used extensively in welding applications for high-temperature components.
Xử lý nhiệt:
- Solid solution treatment (C) at 980-1150°C followed by rapid cooling.
Mechanical Properties (Solution Treated):
- Yield Strength: ≥ 205 MPa
- Tensile Strength: ≥ 520 MPa
- Elongation: ≥ 35%
- Hardness (HBS): ≤ 187
- Hardness (HRB): ≤ 90
- Hardness (HV): ≤ 200
Bản tóm tắt
347 stainless steel, known for its high chromium and nickel content, is enhanced with tantalum and niobium to resist intergranular corrosion. It maintains structural integrity under high temperatures and is particularly suitable for welding applications. After solid solution treatment, it exhibits excellent mechanical properties, making it a preferred choice in industries requiring strength and corrosion resistance.
347/347H Stainless Steel Product Introduction
347 and 347H stainless steels are stabilized austenitic stainless steels known for their excellent resistance to intergranular corrosion. This article provides a comprehensive overview of 347/347H stainless steel, covering its chemical composition, mechanical properties, performance characteristics at different temperatures, industry applications, shapes and sizes, production standards, welding and processing capabilities, advantages and disadvantages, and a comparison with similar alloys.
Thành phần hóa học
347 and 347H stainless steels have similar chemical compositions, with the main difference being the carbon content in 347H for improved high-temperature strength.
| Yếu tố | Composition (%) for 347 | Composition (%) for 347H |
|---|---|---|
| Crom (Cr) | 17.0 – 19.0 | 17.0 – 19.0 |
| Niken (Ni) | 9.0 – 13.0 | 9.0 – 13.0 |
| Mangan (Mn) | tối đa 2.0 | tối đa 2.0 |
| Silic (Si) | 0tối đa 0,75 | 0tối đa 0,75 |
| Cacbon (C) | 0tối đa 0,08 | 0.04 – 0.10 |
| Phốt pho (P) | 0tối đa 0,045 | 0tối đa 0,045 |
| Lưu huỳnh (S) | 0tối đa 0,030 | 0tối đa 0,030 |
| Niobium (Nb) | 10xC – 1.10 | 8xC – 1.10 |
Tính chất cơ học
347/347H stainless steels exhibit excellent mechanical properties suitable for various applications:
| Tài sản | Giá trị |
|---|---|
| Độ bền kéo, ksi (MPa) | 75 (515) min |
| Cường độ năng suất (bù 0,2%), ksi (MPa) | 30 (205) min |
| Độ giãn dài (% tính bằng 2 inch) | 40 min |
| Hardness, Rockwell B (HRB) | 90 max |
Đặc tính hiệu suất
347/347H stainless steels offer several performance advantages:
High Temperature Resistance: Excellent resistance to oxidation and creep at elevated temperatures up to 1000°C.
Intergranular Corrosion Resistance: Contains niobium which stabilizes the alloy against sensitization and intergranular corrosion.
Weldability: Good weldability with standard welding techniques, with care needed to avoid hot cracking.
Ứng dụng công nghiệp
347/347H stainless steels find applications across various industries requiring corrosion resistance and high-temperature performance:
| Ngành công nghiệp | Các ứng dụng |
|---|---|
| Chemical Processing | Reactor vessels, heat exchangers, and piping systems handling corrosive chemicals. |
| Không gian vũ trụ | Exhaust systems, jet engine parts, and aircraft components. |
| Dầu khí | Offshore platforms, oil refinery equipment, and pipelines. |
| Sản xuất điện | Boiler components, superheater tubes, and turbine blades. |
Hình dạng và kích thước
347/347H stainless steels are available in various forms and sizes:
Các hình thức: Sheets, plates, bars, pipes, tubes, and forgings.
Kích thước: Thickness ranging from 0.1 mm to 100 mm for plates, and diameter ranging from 1 mm to 500 mm for round bars.
Tiêu chuẩn sản xuất
347/347H stainless steels conform to international production standards ensuring quality and reliability:
| Mẫu sản phẩm | Hình dạng có sẵn | Kích cỡ có sẵn | Tiêu chuẩn sản xuất |
|---|---|---|---|
| Tấm/tấm | Tấm, tấm | Thickness: 0.1 mm – 100 mm | ASTM A240, ASME SA-240 |
| Thanh/Thanh | Thanh tròn, thanh vuông | Diameter: 1 mm – 500 mm | ASTM A276, ASME SA-276 |
| Pipes/Tubes | Seamless, Welded | OD: 6 mm – 2500 mm | ASTM A312, ASME SA-312 |
Hàn và Gia công
347/347H stainless steels offer good weldability and processing characteristics:
hàn: Can be welded using standard welding techniques such as GTAW (TIG) and GMAW (MIG), with preheating and post-weld heat treatment sometimes required for thick sections.
khả năng gia công: Can be machined using conventional methods, with low cutting speeds and adequate coolant recommended.
Ưu điểm và nhược điểm
| Diện mạo | Chi tiết |
|---|---|
| Thuận lợi | Excellent high-temperature strength and corrosion resistance, good weldability, and intergranular corrosion resistance due to niobium stabilization. |
| Nhược điểm | Higher cost compared to non-stabilized austenitic stainless steels, reduced mechanical properties at cryogenic temperatures. |
So sánh với các hợp kim tương tự
347/347H stainless steels are often compared with other stabilized austenitic stainless steels like 321 and 317L. Here’s a brief comparison:
| Loại hợp kim/Thuộc tính | 347/347H Alloy | 321 Alloy | 317L Alloy |
|---|---|---|---|
| Thành phần hóa học | Contains niobium for stabilization against intergranular corrosion. | Contains titanium for stabilization against sensitization. | Contains molybdenum for improved corrosion resistance in acidic environments. |
| Tính chất cơ học | Higher strength and creep resistance compared to 321. | Similar strength, but lower creep resistance compared to 347. | Lower strength but better corrosion resistance compared to 347. |
| Các ứng dụng | High-temperature applications requiring intergranular corrosion resistance. | Heat exchangers, chemical processing equipment. | Chemical and petrochemical industries requiring corrosion resistance. |
This detailed article introduces 347/347H stainless steel, highlighting its chemical composition, mechanical properties, performance characteristics, industry applications, available forms and sizes, production standards, welding and processing capabilities, as well as advantages, disadvantages, and a comparison with similar alloys. Engineers and professionals seeking a stainless steel alloy with excellent high-temperature performance and corrosion resistance will find 347/347H alloy suitable for a wide range of applications in challenging environments.
