1. Material Composition & Manufacturing Process

5083 aluminum alloy (ASTM B209, EN AW-5083) is a high-strength, non-heat-treatable Al-Mg alloy renowned for exceptional weldability and superior corrosion resistance in marine environments. The ultra-thick forged plate variant offers enhanced mechanical properties through controlled deformation processing:

• Primary Alloying Elements:

• Magnesium (Mg): 4.0-4.9% (primary solid-solution strengthener)
• Manganese (Mn): 0.40-1.0% (grain structure refinement)
• Chromium (Cr): 0.05-0.25% (corrosion resistance enhancement)
• Titanium (Ti): 0.05-0.15% (grain refinement)
  • Base Material:
• Aluminum (Al): ≥92.4% (balance)
  • Controlled Impurities:
• Iron (Fe): ≤0.40% max
• Silicon (Si): ≤0.40% max
• Copper (Cu): ≤0.10% max
• Zinc (Zn): ≤0.25% max

Specialized Ultra-Thick Forging Process:

1. Premium Ingot Production:

• Direct Chill (DC) semi-continuous casting
• Grain refinement with Ti-B additions
• Melt degassing to <0.1ml H₂/100g Al
• Filtration through ceramic foam filters
  2. Homogenization Treatment:
• 500-520°C for 24-36 hours
• Computer-controlled cooling rate
• Microstructural equilibration
  3. Surface Preparation:
• Scalping of segregation layer (minimum 10mm)
• Surface inspection for defects
  4. Preheating for Forging:
• Staged heating to 380-430°C
• Temperature uniformity ±5°C
  5. Multi-Directional Open-Die Forging:
• Initial forging temperature: 400-425°C
• Final forging temperature: 340-380°C
• Deformation ratio: 3:1 to 5:1
• Multi-directional working to optimize properties
• Specialized dies for ultra-thick sections
  6. Controlled Cooling:
• Programmed cooling rate to minimize residual stress
• Air-cooling with thermal blankets for thick sections
  7. Stress Relief Treatment:
• 240-300°C for 1 hour per 25mm thickness
• Furnace cooling to below 200°C
  8. Final Processing:
• Precision machining to customer specifications
• Surface inspection and cleaning
• Protective packaging for shipment

All manufacturing processes are performed under ISO 9001 quality management system with complete traceability.

2. Mechanical Properties of Ultra-Thick 5083 Forged Plate

Property	Minimum	Typical	Test Standard	Ultra-Thick Advantage
Ultimate Tensile Strength	290 MPa	305-330 MPa	ASTM B557	Uniform properties throughout section
Yield Strength (0.2%)	145 MPa	160-185 MPa	ASTM B557	Enhanced through-thickness strength
Elongation (50mm gauge)	12%	16-22%	ASTM B557	Superior ductility across full section
Hardness (Brinell)	85 HB	90-100 HB	ASTM E10	Consistent hardness profile
Shear Strength	175 MPa	185-200 MPa	ASTM B769	Enhanced joint reliability
Fatigue Strength (10⁸)	120 MPa	125-140 MPa	ASTM E466	Improved cyclic loading performance
Compressive Yield	145 MPa	160-190 MPa	ASTM E9	Critical for load-bearing applications
Bearing Strength (e/D=2.0)	385 MPa	400-430 MPa	ASTM E238	Superior fastener performance
Impact Energy (Charpy)	35 J	40-50 J	ASTM E23	Enhanced toughness at low temperatures

Through-Thickness Performance:

• Property variation <5% between surface and core (up to 200mm thickness)
• Directionality ratio (L:LT:ST): 1.00:0.95:0.90 for tensile strength
• Core temperature maintained within critical processing window
• Hardness variation <8 HB from surface to center

3. Microstructural Control for Ultra-Thick Sections

Critical Forging Parameters:

1. Strain Distribution Control:

• Minimum total true strain: 1.1-1.3
• Strain rate: 0.01-0.1 s⁻¹
• Multi-directional working (minimum 25% in secondary direction)
• Intermittent reheating for sections >150mm
  2. Temperature Management:
• Maximum temperature gradient: 30°C across section
• Computer-controlled thermal profile monitoring
• Extended dwell times for temperature homogenization
• Specialized handling equipment for minimal heat loss

Microstructural Characteristics:

• Grain Size: ASTM 5-7 (30-60μm)
• Grain Morphology: Partially recrystallized structure
• Al₆Mn dispersoid distribution: 0.1-0.5μm diameter
• Mg₂Si precipitate control: <0.5 volume percent
• Al-Fe-Mn intermetallic phases: Controlled morphology
• Recrystallized Volume Fraction: 40-60%
• Texture: Mixed deformation/recrystallization texture
• Grain Aspect Ratio: 1.5:1 maximum in final product

Special Features:

• Subgrain structure with high misorientation angles
• Limited recovery due to Mg solute drag effect
• Al₃Mg₂ precipitation controlled to prevent sensitization
• Enhanced dislocation density: 5-8×10¹⁰/cm²

4. Dimensional Specifications & Tolerances

Parameter	Standard Range	Precision Tolerance	Commercial Tolerance
Thickness	150-400 mm	±3 mm	±5 mm
Width	1000-3000 mm	±5 mm	±8 mm
Length	2000-8000 mm	±7 mm	±12 mm
Flatness	N/A	0.2% of length	0.4% of length
Parallelism	N/A	0.6% of thickness	1.0% of thickness
Edge Straightness	N/A	2 mm/m	4 mm/m
Surface Roughness	N/A	6.4 μm Ra max	12.5 μm Ra max

Ultra-Thick Specific Parameters:

• Density: 2.66 g/cm³ (±0.01)
• Weight Calculation: Thickness(mm) × Width(m) × Length(m) × 2.66 = Weight(kg)
• Maximum Single Plate Weight: 20,000 kg
• Machining Allowance: Recommend 15mm per side minimum for critical dimensions
• Stress Relief: Required before precision machining for plates >200mm
• Plate Flatness: Measured under self-weight on flat surface
• Ultrasonic Testing: 100% volumetric inspection available

5. Corrosion Resistance Performance

Environment	Performance	Corrosion Rate	Expected Service Life
Marine Atmosphere	Excellent	<0.02 mm/year	30+ years
Immersed Seawater	Very Good	<0.10 mm/year	25+ years
Industrial Exposure	Excellent	<0.05 mm/year	25+ years
Fresh Water	Excellent	Negligible	40+ years
Stress Corrosion	Excellent	Highly resistant	Design life
Exfoliation	Excellent	EXCO rating EA	Design life
Galvanic Coupling	Fair	Isolation required	Application dependent

Corrosion Protection Options:

• Anodizing:

• Type II (Sulfuric acid): 10-25μm thickness
• Type III (Hard anodize): 25-75μm thickness
• Marine-grade sealing treatments
  • Conversion Coatings:
• Chromate conversion per MIL-DTL-5541
• Chrome-free alternatives for environmental compliance
• Titanium/Zirconium-based treatments
  • Protective Systems:
• Epoxy primer + polyurethane topcoat
• Marine-grade multi-layer systems
• Sacrificial zinc-rich primers
• High-build epoxy coatings for immersion service

Environmental Performance Factors:

• Sensitization Resistance: Superior to 5086 alloy
• NAMLT Test Performance: <15mg/cm²
• IGC Resistance: Excellent after stabilization treatment
• H₂ Embrittlement: Minimal susceptibility

6. Machining & Fabrication Characteristics

Operation	Tool Material	Recommended Parameters	Notes for Ultra-Thick Sections
Heavy Milling	Carbide	Vc=300-600 m/min, fz=0.15-0.30 mm	Climb milling recommended
Deep Hole Drilling	Carbide drills	Vc=60-100 m/min, fn=0.15-0.25 mm/rev	Step drilling for deep holes
Face Milling	PCD cutters	Vc=500-1000 m/min	High positive rake angles
Turning	Carbide/PCD	Vc=200-500 m/min	Rigid setup essential
Tapping	HSS-E taps	Vc=10-20 m/min	50% thread recommended
Sawing	Carbide-tipped	40-60 m/min	Flood coolant mandatory

Fabrication Considerations:

• Forming Limits: Minimum bend radius 2.5× material thickness
• Cold Working: Limited to 15-20% before annealing
• Hot Working: 260-370°C optimal temperature range
• Weldability: Excellent with 5183, 5356, or 5556 filler
• Welding Methods: GMAW, GTAW, FCAW suitable
• Post-weld Treatment: Brush/needle scaling recommended
• Stress Relief After Welding: 200°C for 1 hour per 25mm
• Cutting Methods: Plasma, waterjet, or sawing preferred

7. Welding Performance & Recommendations

Welding Process	Filler Material	Parameters	Special Considerations
GMAW (MIG)	ER5183, ER5556	DCEP, 22-26V, 140-250A	Pulse spray transfer recommended
GTAW (TIG)	ER5183, ER5356	AC, 12-15V, 120-200A	Thoriated tungsten electrodes
FCAW	E5183T, E5556T	DCEP, 24-28V, 150-260A	Minimal interpass cleaning
SAW	ER5183, ER5356	26-30V, 350-550A	Neutral or slightly basic flux

Welding Best Practices for Ultra-Thick Sections:

1. Joint Preparation:

• X-groove or double-V for thickness >25mm
• Root gap 2-4mm
• Root face 1-3mm
• Bevel angle 50-60°
• Thorough degreasing with acetone or MEK
  2. Preheating:
• Generally not required
• For sections >200mm, preheat 50-80°C to reduce thermal gradient
  3. Interpass Temperature:
• Maximum 120°C
• Monitor with infrared thermometer
  4. Post-weld Treatment:
• Stress relief recommended for thick sections
• Thorough cleaning of flux and spatter
  5. Inspection Methods:
• Visual inspection per AWS D1.2
• Radiographic or ultrasonic testing for critical joints
• Dye penetrant for surface defects

8. Physical Properties for Engineering Design

Property	Value	Design Implications
Density	2.66 g/cm³	Weight calculations and buoyancy
Melting Range	574-638°C	Welding and heat treatment parameters
Thermal Conductivity	117 W/m·K	Heat dissipation in thermal applications
Electrical Conductivity	29% IACS	Electrical applications and design
Specific Heat Capacity	900 J/kg·K	Thermal inertia calculations
Thermal Expansion	23.8 ×10⁻⁶/K	Expansion joint design and thermal stress
Young’s Modulus	71 GPa	Structural stiffness and deflection
Poisson’s Ratio	0.33	Strain relationships in complex loading
Damping Capacity	Moderate (0.01-0.02)	Vibration control applications

Environmental Performance:

• Operating Temperature Range: -196°C to +200°C
• Cryogenic Performance: Excellent toughness retention
• Fire Resistance: Non-combustible
• Magnetic Properties: Non-magnetic
• Radiation Resistance: Excellent
• Recyclability: 100% recyclable with no quality loss
• Environmental Impact: Lower energy footprint than steel

9. Quality Assurance & Testing Protocol

Standard Inspection Regime:

1. Chemical Composition Testing:

• Optical emission spectroscopy
• Verification of all alloying elements
  2. Mechanical Testing:
• Tensile testing (longitudinal and transverse directions)
• Hardness mapping (surface and cross-section)
• Impact testing for critical applications
  3. Non-Destructive Testing:
• Ultrasonic inspection per ASTM A578/A578M
• Dye penetrant inspection for surface defects
  4. Dimensional Inspection:
• CMM verification of critical dimensions
• Thickness mapping at specified grid points
• Flatness measurement under self-weight
  5. Microstructural Analysis:
• Grain size determination
• Inclusion rating per ASTM E45
• Sensitization testing for H tempers
• Metallographic examination

Certification Options:

• Mill Test Report (EN 10204 3.1)
• Third-party inspection certification (EN 10204 3.2)
• DNV-GL certification for marine applications
• ABS certification for marine structures
• Lloyd’s Register certification
• Customer-specific certification requirements
• Material traceability documentation
• Production record documentation

10. Industrial Applications & Use Cases

Primary Applications:

• Naval and commercial shipbuilding
• Offshore oil & gas platforms
• Pressure vessel components
• Cryogenic storage and transport
• Heavy transportation structures
• Bridge decking and structural components
• Defense industry applications
• Chemical processing equipment
• Mining equipment structures
• Marine propulsion system components

Specific Use Cases:

1. LNG Carrier Structural Components:

• Superior low-temperature toughness
• Excellent weldability for complex structures
• Good strength-to-weight ratio