5052 Large Diameter Aluminum Forged Ring

 

The 5052 large diameter aluminum alloy forged ring is a moderate-strength, non-heat-treatable aluminum-magnesium alloy (Al-Mg series), known for its excellent corrosion resistance (especially in marine and industrial environments), superior formability, good weldability, and moderate strength. Although its strength is lower than that of 5083 alloy, 5052 offers better cold formability and higher fatigue strength/endurance limit. Through precise forging, particularly for large diameter rings, its internal microstructure is optimized, with grain flow aligned along the ring’s geometry, making this material an ideal choice for applications requiring high corrosion resistance, formability, weldability, moderate strength, and performance in large structural components, such as marine parts, pressure vessels, electronic equipment enclosures, and storage tanks.

Primary Alloying Elements:

Magnesium (Mg): 2.2-2.8% (primary strengthening element, provides strength and good weldability)

Chromium (Cr): 0.15-0.35% (inhibits recrystallization, improves stress corrosion resistance, refines grain)

Base Material:

Aluminum (Al): Balance

Controlled Impurities:

Iron (Fe): 0.40% max

Silicon (Si): 0.25% max

Copper (Cu): 0.10% max

Manganese (Mn): 0.10% max

Zinc (Zn): 0.10% max

Other elements: 0.05% max each, 0.15% max total

Premium Forging Process (for Large Diameter Rings): The production of 5052 large diameter aluminum alloy forged rings, despite their relatively lower strength, similarly demands precise control over the forging process to ensure internal quality, grain flow, and dimensional stability:

Melt Preparation:

High-purity primary aluminum (99.7% minimum)

Precise control of alloying element content, especially magnesium and chromium, with a tolerance of ±0.03%

Advanced filtration and degassing treatments (e.g., inert gas sparging, SNIF, vacuum degassing) ensure ultra-high melt cleanliness, minimizing inclusions

Grain refinement (typically with Al-Ti-B master alloy) to obtain a uniform and fine as-cast structure

Specially designed Direct-Chill (DC) casting systems for producing large-sized ingots with high internal quality.

Homogenization:

Multi-stage homogenization at 400-430°C for 10-24 hours (depending on ingot size)

Uniform temperature control: ±3°C, ensuring uniform distribution of alloying elements, elimination of macro-segregation, and improved ductility.

Billet Preparation:

Ingot surface conditioning (scalping or milling) to remove surface defects.

100% ultrasonic inspection to ensure internal flawlessness (conforming to AMS 2630 class A1 or ASTM E2375 Level 2).

Preheating: 350-380°C, with precise temperature uniformity control to ensure ductility before deformation.

Forging Sequence (Large Diameter Ring Forgings):

Upsetting: Multiple upsetting steps of large ingots at 350-380°C to break down the as-cast structure and form a pancake or disk-shaped preform.

Piercing: Creating a central hole on large hydraulic presses using dies or mandrels, gradually forming the annular hole and compressing the ring wall, further refining grains.

Ring Rolling: The critical ring rolling process on large diameter ring rolling machines. Through axial and radial reduction, grain flow is highly aligned circumferentially along the ring, eliminating internal voids and porosity, improving density and circumferential properties. Ring rolling is typically performed in multiple passes to ensure uniform deformation and avoid defects.

Forging Temperature: 320-370°C (precisely controlled) to prevent excessive grain growth and cracking.

Forging Pressure: Thousands to tens of thousands of tons using large hydraulic presses and ring rolling machines to ensure sufficient deformation of large billets.

Minimum Reduction Ratio: 3:1 to 5:1, ensuring dense, uniform internal structure, complete elimination of as-cast structure, and formation of optimized grain flow.

Annealing (Optional):

If further processing is required or if sensitivity to residual stress is a concern, annealing (O temper) can be performed after forging to lower hardness and improve ductility.

Subsequent Work Hardening and Stabilization Treatments (to form H tempers):

H32: Strain hardened to a quarter hard temper, achieved by controlled cold working.

H34: Strain hardened to a half hard temper, higher hardness than H32.

H321: Stabilized H32 temper, providing excellent stress corrosion resistance (although 5052 itself has low SCC susceptibility).

H112: Flattened only after forging, retaining the as-forged condition, suitable for further processing before machining.

All production stages are subject to stringent quality control, non-destructive testing, and traceability management, especially for the internal quality control of large diameter rings.

 

Property	H112	H32	H34	O	Test Method
Ultimate Tensile Strength	205-240 MPa	215-255 MPa	230-270 MPa	170-205 MPa	ASTM E8
Yield Strength (0.2%)	80-120 MPa	145-185 MPa	170-210 MPa	60-90 MPa	ASTM E8
Elongation (2 inch)	16-25%	10-18%	8-15%	20-28%	ASTM E8
Hardness (Brinell)	50-65 HB	65-75 HB	70-80 HB	40-50 HB	ASTM E10
Fatigue Strength (5×10⁸ Cycles)	100-130 MPa	110-140 MPa	120-150 MPa	70-100 MPa	ASTM E466
Shear Strength	120-150 MPa	130-160 MPa	140-170 MPa	100-130 MPa	ASTM B769

 

Property Distribution:

Radial vs. Tangential properties: Large diameter forged rings, through ring rolling, have grain flow highly aligned circumferentially along the ring, providing excellent tangential strength, fatigue resistance, and fracture toughness. Radial and axial properties may be slightly lower, but the difference is controlled.

Wall thickness effect on properties: The strength of 5052 alloy is relatively less sensitive to wall thickness, but in large diameter thick-walled rings, the forging process ensures uniformity of core and surface properties.

Core to surface hardness variation: Less than 5 HB.

Residual Stress: H112 temper retains some residual stress from forging. H321 temper significantly reduces residual stress through stabilization treatment and improves stress corrosion resistance.

Fatigue Performance: Optimized grain flow and dense microstructure formed by the forging process significantly improve the material’s fatigue life and resistance to fatigue crack propagation, which is particularly critical in large structural components.

 

Key Microstructural Features:

Grain Structure:

Fine, uniform mixed structure of recrystallized grains and elongated non-recrystallized grains aligned tangentially.

Grain flow highly matched with the ring’s geometry, uniformly distributed tangentially, maximizing material performance.

Fine dispersoids formed by Chromium (Cr) effectively inhibit grain growth and recrystallization, maintaining grain refinement.

ASTM grain size 7-10 (32-11μm), or finer grains.

Precipitate Distribution:

Mg₂Al₃ phase: Fine and uniformly dispersed, acting as the primary strengthening phase, but with lower precipitation amount and tendency compared to 5083 alloy, thus lower sensitization risk at high temperatures.

Grain boundary precipitates are effectively controlled to ensure excellent corrosion resistance.

Small amounts of primary intermetallic compounds formed by impurities like Fe and Si are effectively broken down and dispersed, with controlled size and quantity.

Texture Development:

Forging process creates specific texture beneficial for tangential properties, optimizing strength, toughness, and fatigue resistance.

Special Features:

High-quality metallurgical cleanliness, minimizing non-metallic inclusion defects through advanced melting and casting technologies.

 

Parameter	Standard Range	Precision Tolerance	Commercial Tolerance	Test Method
Outer Diameter	500-4000+ mm	±1.0mm up to 1000mm	±2.0mm up to 1000mm	Micrometer/CMM
		±0.1% above 1000mm	±0.2% above 1000mm
Inner Diameter	400-3900+ mm	±1.0mm up to 1000mm	±2.0mm up to 1000mm	Micrometer/CMM
		±0.1% above 1000mm	±0.2% above 1000mm
Wall Thickness	50-600+ mm	±0.5mm	±1.0mm	Micrometer/CMM
Height	50-800+ mm	±0.5mm	±1.0mm	Micrometer/CMM
Flatness	N/A	0.3mm/m	0.6mm/m	Flatness Gauge/CMM
Concentricity	N/A	0.3mm	0.6mm	Concentricity Gauge/CMM
Surface Roughness	N/A	6.3 μm Ra max	12.5 μm Ra max	Profilometer

 

Standard Available Forms:

Forged Rings: Outer diameter up to 4000mm+, wall thickness up to 600mm+.

Custom dimensions and geometries available according to customer drawings and requirements, offering various conditions from as-forged blanks to rough or finish machined states.

Available in various work-hardened tempers, such as O, H112, H32, H34, H321.

 

Temper Code	Process Description	Optimal Applications	Key Characteristics
O	Fully annealed, softened	Maximum formability needed, or for subsequent deep processing	Maximum ductility, lowest strength
H112	Flattened only after forging	Suitable for further processing before machining, with residual stress from forging	As-forged condition, moderate strength, excellent corrosion resistance
H32	Cold worked to quarter-hard temper	Applications requiring a balance of strength and formability	Moderate strength, good formability
H34	Cold worked to half-hard temper	Higher strength than H32, slightly lower formability	Higher strength, moderate formability
H321	Stabilized H32 temper	Strict corrosion resistance requirements, reduced residual stress	Excellent corrosion resistance, lower residual stress

 

Temper Selection Guidance:

O: When complex cold forming operations are required for large diameter rings, or as an initial state for subsequent processing.

H112: When utilizing the as-forged microstructure and properties, and further processing is required.

H32/H34: When increased strength is desired through cold working, while maintaining a degree of formability.

H321: When higher corrosion resistance is required, and further reduction of residual stress is beneficial.

 

Operation	Tool Material	Recommended Parameters	Comments
Turning	Carbide, PCD	Vc=200-700 m/min, f=0.15-0.6 mm/rev	Easy to achieve good surface finish, attention to chip evacuation
Drilling	Carbide, TiN coated	Vc=70-200 m/min, f=0.1-0.35 mm/rev	Through-coolant drills recommended, good for deep holes
Milling	Carbide, HSS	Vc=300-900 m/min, fz=0.1-0.4 mm	High-positive rake angle tools, large depth of cut, high feed
Tapping	HSS-E-PM, TiCN coated	Vc=20-40 m/min	Proper lubrication for good thread quality
Grinding	Aluminum oxide, CBN wheels	Use with caution, can cause surface burns and residual stress	Strict control of parameters and cooling if necessary
Polishing	Soft wheels, abrasive paste	Improves surface finish, reduces stress concentration	Clean surface after polishing

 

Fabrication Guidance:

Machinability Rating: 85% (1100 aluminum = 100%), good machinability, superior to 5083, 2xxx, and 7xxx alloys, but lower than 6xxx series alloys.

Chip Formation: Chips tend to wrap around tools, requires good chip breakers and high-flow coolant.

Coolant: Water-soluble cutting fluid (8-12% concentration), high flow rate cooling.

Tool Wear: Low, long tool life.

Weldability: Excellent with TIG and MIG welding, one of the best weldable aluminum alloys, with high weld strength, suitable for assembly of large complex structures; typically no post-weld heat treatment needed.

Cold Working: Excellent formability in O temper, good in H32/H34 tempers.

Hot Working: Recommended temperature range 300-370°C, with strict control over deformation amount and rate.

Stress Corrosion Cracking: 5052 alloy itself is not susceptible to SCC; H321 temper further enhances SCC resistance.

Cryogenic Properties: Strength and toughness are well-maintained in extremely low-temperature environments.

 

Environment Type	Resistance Rating	Protection Method	Expected Performance
Industrial Atmosphere	Excellent	Clean surface	20+ years
Marine Atmosphere	Excellent	Clean surface	15-20+ years
Seawater Immersion	Excellent	Cathodic protection or painting	10-20+ years with maintenance
High Humidity	Excellent	Clean surface	20+ years
Stress Corrosion	Excellent	No additional protection needed	Extremely low susceptibility
Exfoliation	Excellent	Standard protection	Extremely low susceptibility
Galvanic Corrosion	Good	Proper isolation	Careful design with dissimilar metals

 

Surface Protection Options:

Anodizing:

Type II (Sulfuric): 10-25μm thickness, provides additional protection and aesthetics.

Type III (Hard): 25-75μm thickness, increases wear resistance and hardness (though effects may be less pronounced than on harder alloys).

Conversion Coatings:

Chromate conversion coatings (MIL-DTL-5541): Excellent base for paints or adhesives.

Chromium-free alternatives: Environmentally compliant.

Painting Systems:

Epoxy primer + polyurethane topcoat: Provides excellent long-term protection, especially for marine and offshore applications.

 

Property	Value	Design Consideration
Density	2.68 g/cm³	Lightweight design, center of gravity control
Melting Range	605-650°C	Welding and casting parameters
Thermal Conductivity	138 W/m·K	Thermal management, heat transfer design
Electrical Conductivity	35% IACS	Electrical conductivity in electrical applications
Specific Heat	900 J/kg·K	Thermal mass and heat capacity calculations
Thermal Expansion (CTE)	23.8 ×10⁻⁶/K	Dimensional changes due to temperature variations
Young’s Modulus	70.3 GPa	Deflection and stiffness calculations
Poisson’s Ratio	0.33	Structural analysis parameter
Damping Capacity	Moderate	Vibration and noise control

 

Design Considerations:

Operating Temperature Range: -200°C to +80°C (long-term use above 80°C will gradually reduce strength).

Cryogenic Performance: Strength and toughness are well-maintained in extremely low-temperature environments, making it an excellent cryogenic structural material.

Magnetic Properties: Non-magnetic.

Recyclability: 100% recyclable with high scrap value.

Formability: Excellent formability in as-forged O temper, good in H32/H34 tempers.

Dimensional Stability: Good dimensional stability after forging and stabilization treatment.

Strength-to-Weight Ratio: Significant advantage in large structural components requiring good corrosion resistance, weldability, formability, and moderate strength.

 

Standard Testing Procedures:

Chemical Composition:

Optical emission spectroscopy

X-ray fluorescence analysis

Verification of all major elements and impurity content

Mechanical Testing:

Tensile testing (radial, tangential, axial, especially for thick-walled rings, samples needed at different depths)

Hardness testing (Brinell, multiple locations)

Fatigue testing (as required)

Nondestructive Testing:

Ultrasonic inspection (100% volumetric, especially for internal quality of large diameter thick-walled forgings, conforming to AMS 2630 class A1/AA or ASTM E2375 Level 2)

Eddy current testing (surface and near-surface defects)

Penetrant inspection (surface defects)

Microstructural Analysis:

Grain size determination

Precipitate and intermetallic compound evaluation

Grain flow pattern verification

Recrystallization degree assessment

Dimensional Inspection:

CMM (Coordinate Measuring Machine) verification

Outer diameter, inner diameter, wall thickness, height, flatness, concentricity, etc., with comprehensive geometric dimensional control for large rings.

Standard Certifications:

Mill Test Report (EN 10204 3.1 or 3.2)

Chemical analysis certification

Mechanical properties certification

Heat treatment/forging certification

Nondestructive testing certification

Conformance to ASTM B247 (forgings), GB/T 3880 (Chinese standard), EN AW-5052, and other industry standards.

 

Primary Applications:

Marine Industry:

Ship and yacht structural components (decks, bulkheads, seawater piping, tanks, component support rings)

Non-load-bearing structural components for offshore platforms

Pressure Vessels and Storage Tanks:

Shells, heads, and flange rings for low to medium-pressure storage tanks and vessels

Electronic equipment chassis and enclosures, heat sinks

Transportation:

Automotive and truck fuel tanks, gas tanks

Non-load-bearing structural components for railway vehicles

Construction and Decoration:

Architectural curtain walls, decorative elements, structural support rings

General Industry:

Various general-purpose annular structures requiring good formability, corrosion resistance, and moderate strength

Design Advantages:

Excellent corrosion resistance, especially in marine and industrial environments.

Superior weldability, with high weld strength and good ductility, suitable for assembly of large complex structures.

Excellent cold formability and machinability, easy to manufacture.

Forging process optimizes grain flow and internal quality, improving fatigue resistance.

Good moderate strength and toughness, sufficient for most general structural requirements.

Cost-effectiveness: Compared to high-strength alloys, 5052 offers a cost advantage while ensuring good performance.

Lightweight, contributing to energy savings and emission reduction.

Design Limitations:

Lower strength than 5083, 6xxx, and 7xxx series high-strength alloys; not suitable for applications requiring extremely high load-bearing capacity.

Cannot be strengthened by heat treatment; strength can only be increased through cold working (H tempers).

Long-term use at temperatures above 80°C will gradually reduce strength.

Economic Considerations:

More competitive material and processing costs compared to high-strength aluminum alloys.

Excellent corrosion resistance reduces long-term maintenance and replacement needs, lowering total life cycle costs.

Good weldability and formability reduce the manufacturing difficulty and cost of complex large structures.

Sustainability Aspects:

100% recyclable, high resource recycling rate, conforming to green manufacturing concepts.

Energy consumption and carbon emissions in aluminum production processes are continuously optimized.

Long product lifespan and high reliability reduce waste generation.

Material Selection Guidance:

Choose 5052 large diameter forged rings when good corrosion resistance (especially to seawater), excellent weldability, superior formability, and moderate strength are simultaneously required for large annular structures.

Suitable for cost-sensitive applications that do not require extreme strength, such as marine vessels, storage tanks, and electronic equipment enclosures.

For applications requiring higher strength along with excellent corrosion resistance, 5083 alloy can be considered.