Laser Cutting of 904L Stainless Steel Plates

1. Overview of 904L Stainless Steel Plates

1.1 Key Parameters

• Chemical Composition: Cr (19-23%), Ni (23-28%), Mo (4-5%), Cu (1-2%), C (≤0.02%), Si (≤1%), Mn (≤2%), P (≤0.03%), S (≤0.01%), N (≤0.1%). The synergistic effect of Cr, Ni, Mo, and Cu enhances resistance to both uniform and localized corrosion (e.g., pitting, crevice corrosion).
• Mechanical Properties:
  • Tensile strength: 490-690 MPa
  • Yield strength: ≥215 MPa
  • Elongation: ≥35%
  • Hardness: ≤230 HBW
  • Corrosion Resistance: Excellent in reducing acids (e.g., sulfuric acid up to 50°C) and chloride-rich environments (pitting resistance equivalent number, PREN ≥40).

1.2 Common Sizes

• Thickness: Typically 0.8 mm to 100 mm (custom thicknesses available for specialized equipment).
• Width & Length: Standard sizes include 1220×2440 mm, 1500×3000 mm, 2000×6000 mm. Larger or smaller sizes can be produced via cutting or rolling for specific projects.

1.3 Standards

• ASTM A240/A240M (USA)
• EN 10088-4 (Europe)
• JIS G4305 (Japan)
• GB/T 3280 (China)

1.4 Key Characteristics

• Superior Corrosion Resistance: Outperforms standard austenitic steels (e.g., 316L) in harsh environments, including sulfuric acid, acetic acid, and seawater, due to its high Mo and Cu content.
• Good Mechanical Properties: Balances strength and ductility, allowing for forming, bending, and welding without compromising integrity.
• Resistance to Stress Corrosion Cracking (SCC): Performs well in chloride-induced SCC scenarios, critical for offshore or chemical processing applications.
• Weldability: Can be welded using TIG or MIG methods with matching fillers, though low carbon content minimizes carbide precipitation.

1.5 Applications

• Chemical Processing: Storage tanks, pipelines, and reactors handling sulfuric acid, phosphoric acid, and organic acids.
• Oil & Gas: Offshore platforms, subsea equipment, and desalination plants (resistant to seawater and brines).
• Pharmaceuticals: Equipment for sterile processing and acid-based cleaning solutions.
• Food & Beverage: Machinery for acidic food processing (e.g., citrus juices) to prevent contamination.
• Pollution Control: Scrubbers and waste treatment systems handling corrosive effluents.

2. Laser Cutting of 904L Stainless Steel Plates

2.1 Advantages of Laser Cutting

• Exceptional Precision: Achieves tight tolerances (±0.03 mm) and smooth, burr-free edges (Ra ≤10 μm), critical for sealing surfaces in chemical tanks or pressure vessels.
• Minimal Heat-Affected Zone (HAZ): Laser cutting limits HAZ to 0.05-0.3 mm, preserving 904L’s corrosion resistance (unlike plasma cutting, which may expand HAZ and compromise anti-corrosive properties).
• Complex Geometry Handling: Easily cuts intricate shapes (e.g., custom flanges, precision slots, or curved profiles) that are difficult with mechanical methods like milling or sawing.
• Non-Contact Process: Eliminates tool wear and material deformation, ensuring consistent quality across large batches—vital for 904L, a high-cost material where waste must be minimized.
• Efficiency: Faster than waterjet cutting for thin to medium thicknesses (0.8-25 mm), reducing lead times for both prototypes and mass production.
• Narrow Kerf: A kerf width of 0.1-0.4 mm minimizes material loss, optimizing cost-efficiency for expensive 904L plates.

2.2 Processing Range

• Thickness: 0.8 mm to 30 mm (using fiber lasers with 6-15 kW power; thicker plates may require higher power or oxygen assist gas to enhance melting).
• Size Capacity: Handles large plates up to 6000×2000 mm, with automated systems enabling continuous processing for industrial-scale orders.
• Design Flexibility: Supports 2D cutting of any CAD-designed shape, from simple rectangles to complex components like chemical reactor internals or offshore flange patterns.