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ASTM A193 Grade B8M 347H Stainless Steel Bar
- High-Temperature Performance: Stabilized with niobium (Nb) to prevent chromium carbide precipitation, maintaining corrosion resistance at 800-1500°F (427-816°C).
- Corrosion Resistance: Superior oxidation and scaling resistance in sulfur-rich environments.
- Weldability: Lower carbon content reduces intergranular corrosion risk post-weld.
Chemical Composition (wt%)
Element | Content Range |
C | ≤0.08 |
Si | ≤1.00 |
Mn | ≤2.00 |
P | ≤0.045 |
S | ≤0.030 |
Cr | 17.0-19.0 |
Ni | 9.0-13.0 |
Nb | ≥10×C |
Others | Fe Balance |
Property | Value |
Diameter Range | 10mm – 300mm |
Hardness (HB) | ≤187 |
Density | 7.93 g/cm³ |
Yield Strength | ≥35 ksi (241 MPa) |
Tensile Strength | ≥75 ksi (517 MPa) |
I. Material Properties
Chemical Composition
Basic Ratio: 18Cr-10Ni-0.1Nb (mass fraction)
Trace Elements: N ≤ 0.11% (controls intergranular corrosion)
Impurity Standard: Cu ≤ 0.75% (prevents thermal brittleness)
High-Temperature Performance
Creep Resistance: Time to Fracture ≥ 2000 h at 700°C/100 MPa
Thermal Fatigue Resistance: Cycle Life > 5000 cycles at ΔT = 500°C
Mechanical Parameters
High-Temperature Yield: ≥ 120 MPa at 800°C
Hardness Gradient: Hardness Drop ≤ 15% from 20°C to 600°C
II. Application Scenarios
Energy Sector
Ultra-supercritical Units: Main Steam Piping (Design Pressure ≥ 31 MPa) )
Nuclear Power Plant: Pressurizer Safety Terminal (Seismic Resistance Level 1E)
Chemical Equipment
Ethylene Cracking Furnace: Radiant Section Tubes (Carburization Resistance Thickness ≤ 0.5mm)
Sulfur Recovery Unit: High-Temperature Flanges (H₂S Corrosion Rate ≤ 0.1mm/year)
Special Environments
Offshore Platform: Desalination Heat Exchanger (Cl⁻ Concentration Tolerance ≥ 20,000ppm)
Biopharmaceutical: Fermentation Tank Agitator Shaft (Surface Roughness Ra ≤ 0.8μm)
III. Processing Guidelines
Heat Treatment Process
Solution Temperature: 1040-1120°C (Water Quenching)
Stabilization Treatment: 850-930°C (Air Cooling)
Welding Specifications
Compatible Welding Material: ERNiCrFe-7 (AWS A5.14)
Interpass Temperature: ≤ 150°C (To prevent σ phase precipitation)
Surface Treatment
- Polished: Ra ≤0.8μm for precision components.
- Pickled: Removes oxide scale for better corrosion resistance.
Why Choose Us ?
- Certified: ISO 9001, PED 2014/68/EU.
- Customizable: Tailored dimensions and heat treatments.
Applications & Industries
Aerospace:
High-power density actuators.
Electronics:
Precision sensors & MEMS components.
Energy:
Magnetic coupling devices for turbines.
Frequently Asked Questions
Q1: What is the max service temperature?
A1: 1500°F (816°C) in cyclic conditions.
Q2: Does it require post-weld annealing?
A2: Not typically due to Nb stabilization.
Q3: How to distinguish 347H from 347?
A: 347H has higher carbon content (≥0.04%) for enhanced high-temperature strength, while 347 (C≤0.08%) is for general corrosion resistance.
Q4: Surface treatment options?
A: Shot peening can refine surface grains to ~100nm, improving fatigue resistance.
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