5a06 H112 Aluminum Forged Ring

5A06 H112 aluminum forged ring is a high-strength, non-heat-treatable aluminum-magnesium alloy (Al-Mg series) particularly renowned for its excellent corrosion resistance (especially to seawater), good weldability, moderate strength, and superior cryogenic properties. The H112 temper indicates that the material has been forged and subsequently not subjected to precise cold working or heat treatment, thus retaining its forged microstructure and some residual stress. Through a precise forging process, its internal microstructure is optimized, with grain flow aligned along the ring’s geometry, making it an ideal choice for applications demanding extreme corrosion resistance, weldability, and cryogenic toughness, such as shipbuilding, offshore engineering, nuclear industry, cryogenic equipment, and pressure vessels:

Primary Alloying Elements:

Magnesium (Mg): 5.8-6.8% (primary strengthening element, provides high strength and good weldability)

Manganese (Mn): 0.5-0.8% (further enhances strength and refines grain)

Chromium (Cr): 0.10-0.20% (inhibits recrystallization, improves stress corrosion resistance)

Titanium (Ti): 0.02-0.10% (grain refinement)

Base Material:

Aluminum (Al): Balance

Controlled Impurities:

Iron (Fe): ≤0.25% max

Silicon (Si): ≤0.40% max

Copper (Cu): ≤0.10% max

Zinc (Zn): ≤0.20% max

Beryllium (Be): 0.0001-0.005% (inhibits oxidation)

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

Premium Forging Process:

Melt Preparation:

High-purity primary aluminum

Precise control of alloying elements with ±0.05% tolerance

Advanced filtration and degassing treatments (e.g., SNIF or rotary degassing) ensure melt cleanliness

Grain refinement (typically with Al-Ti-B master alloy)

Direct-Chill (DC) semi-continuous casting to produce high-quality ingots

Homogenization:

450-480°C for 8-16 hours

Uniform temperature control: ±5°C

Ensures uniform distribution of alloying elements and eliminates microsegregation

Billet Preparation:

Ingot surface conditioning (scalping or milling)

Ultrasonic inspection to ensure internal flawlessness

Preheating: 380-420°C, with precise temperature uniformity control

Forging Sequence (Ring Forging):

Upsetting: Forging the ingot into a disk or preform ring at 380-420°C

Piercing/Punching: Creating a central hole using intermediate dies or mandrels, gradually forming the ring shape

Ring Rolling: Using a ring rolling machine to axially and radially expand the ring preform, further refining grain structure and controlling dimensions

Die Forging Finish: Final shaping in dies to ensure geometric precision and surface finish

Forging Temperature: 350-400°C

Forging Pressure: Thousands of tons, depending on ring size and complexity

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

Annealing (Optional):

If further processing or microstructural adjustment is needed, annealing can be performed after forging to achieve the O temper.

H112 Temper Formation:

After forging, the material undergoes only minor mechanical processing (if needed), such as flattening or straightening, without further heat treatment or cold working, retaining its as-forged condition.

All production stages are subject to stringent quality control, non-destructive testing, and traceability management.

 

Property	H112	Test Method
Ultimate Tensile Strength	300-340 MPa	ASTM E8
Yield Strength (0.2%)	150-180 MPa	ASTM E8
Elongation (2 inch)	16-22%	ASTM E8
Hardness (Brinell)	70-85 HB	ASTM E10
Fatigue Strength (5×10⁸ Cycles)	120-150 MPa	ASTM E466
Shear Strength	170-200 MPa	ASTM B769
Fracture Toughness (K1C, typical)	28-35 MPa√m	ASTM E399

 

Property Distribution:

Radial vs. Tangential properties: Forged rings exhibit good anisotropy, with grain flow distributed tangentially (circumferentially), providing higher tangential strength and fatigue resistance.

Wall thickness effect on properties: Strength may slightly increase in thinner wall sections.

Core to surface hardness variation: Less than 5 HB.

Residual Stress: H112 temper retains some residual stress from forging; if sensitivity to residual stress is a concern, subsequent processing may require stress relief.

Fatigue Performance: Optimized grain flow formed by the forging process helps improve the material’s fatigue life.

Cryogenic Performance: Strength and toughness even improve in extremely low-temperature environments, with no brittle transition, making it an excellent cryogenic structural material.

 

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 Manganese (Mn), Chromium (Cr), and Titanium (Ti) effectively inhibit grain growth and recrystallization

ASTM grain size 6-9 (45-16μm)

Precipitate Distribution:

β-Mg₅Al₈ phase: Fine and uniformly dispersed, acting as the primary strengthening phase

Mg-Al intermetallic compounds: Distribution at grain boundaries effectively controlled to avoid stress corrosion sensitivity

Small amounts of primary intermetallic compounds like AlFeMn are effectively broken down and dispersed

Texture Development:

Forging process creates specific texture beneficial for tangential properties

Special Features:

High metallurgical cleanliness, minimizing non-metallic inclusion defects

Controlled continuous precipitation of beta-phase at grain boundaries enhances stress corrosion resistance

 

Parameter	Standard Range	Precision Tolerance	Commercial Tolerance	Test Method
Outer Diameter	100-2000 mm	±0.8mm up to 500mm	±1.5mm up to 500mm	Micrometer/CMM
		±0.2% above 500mm	±0.4% above 500mm
Inner Diameter	80-1900 mm	±0.8mm up to 500mm	±1.5mm up to 500mm	Micrometer/CMM
		±0.2% above 500mm	±0.4% above 500mm
Wall Thickness	10-400 mm	±0.5mm	±1.0mm	Micrometer/CMM
Height	20-600 mm	±0.5mm	±1.0mm	Micrometer/CMM
Flatness	N/A	0.2mm/100mm Diameter	0.4mm/100mm Diameter	Flatness Gauge/CMM
Concentricity	N/A	0.2mm	0.4mm	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 100mm to 2000mm, wall thickness 10mm to 400mm

Custom dimensions and geometries available according to customer drawings and requirements

Various processing conditions available, e.g., Forged As-Is, Rough Machined

 

Temper Code	Process Description	Optimal Applications	Key Characteristics
O	Fully annealed, softened	Applications requiring maximum formability, or subsequent deep processing	Maximum ductility, lowest strength
H111	Moderately strain hardened after full annealing	General structures, excellent post-weld properties	Good balance of strength and ductility
H112	Flattened only after forging	Suitable for further processing before machining, with residual stresses from forging	As-forged condition, moderate strength, excellent corrosion resistance
H321	Stabilized H32 temper	High strength, strict corrosion resistance requirements	Excellent SCC resistance, higher strength

 

Temper Selection Guidance:

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

O: When complex cold forming operations or maximum ductility are needed for the ring.

H111: When higher strength than H112 is required, while maintaining good ductility and weldability.

H321: When extremely high requirements for corrosion resistance (especially stress corrosion cracking) are present, along with higher strength demands.

As an Al-Mg series alloy, 5A06 is not strengthened by heat treatment; different H tempers are primarily achieved through cold working. Forging itself is a form of plastic deformation, thus H112 represents the as-forged condition.

 

Operation	Tool Material	Recommended Parameters	Comments
Turning	Carbide, PCD	Vc=150-400 m/min, f=0.1-0.4 mm/rev	Easy to achieve good surface finish, moderate tool wear
Drilling	Carbide, TiN coated	Vc=60-150 m/min, f=0.15-0.35 mm/rev	Through-coolant drills recommended, good for deep holes
Milling	Carbide, HSS	Vc=200-600 m/min, fz=0.1-0.25 mm	High-positive rake angle tools, large depth of cut, high feed
Tapping	HSS-E-PM, TiCN coated	Vc=15-30 m/min	Proper lubrication for good thread quality
Reaming	Carbide, HSS	Vc=50-100 m/min, f=0.2-0.5 mm/rev	H7/H8 tolerance achievable
Sawing	Carbide-tipped blade	Vc=800-2000 m/min	Efficient cutting for large diameter bars

 

Fabrication Guidance:

Machinability Rating: 70% (1100 aluminum = 100%), good machinability, lower than 2xxx and 7xxx alloys

Chip Formation: Gummy chips, tend to wrap around tools, requires good chip breakers

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

Tool Wear: Moderate, regular tool inspection needed

Weldability: Excellent with TIG and MIG welding, one of the best weldable aluminum alloys

Cold Working: Good formability in O temper, moderate in H112 temper

Hot Working: Recommended temperature range 300-400°C

Stress Corrosion Cracking: H112 temper has excellent resistance to stress corrosion cracking

Cryogenic Properties: Retains or improves strength and toughness at extremely low temperatures

 

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	Very Good	Cathodic protection or painting	10-15+ years with maintenance
High Humidity	Excellent	Clean surface	20+ years
Stress Corrosion	Excellent (H112 temper)	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

Dyeing and sealing: Enhances aesthetics and corrosion resistance

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 applications

 

Property	Value	Design Consideration
Density	2.66 g/cm³	Lightweight design, center of gravity control
Melting Range	575-635°C	Welding and casting parameters
Thermal Conductivity	121 W/m·K	Thermal management, heat transfer design
Electrical Conductivity	34% IACS	Electrical conductivity in electrical applications
Specific Heat	897 J/kg·K	Thermal mass and heat capacity calculations
Thermal Expansion (CTE)	24.0 ×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 this temperature may lead to sensitization, affecting SCC resistance)

Cryogenic Performance: Maintains or improves strength and toughness at extremely low temperatures, ideal for cryogenic structural materials

Magnetic Properties: Non-magnetic

Recyclability: 100% recyclable with high scrap value

Formability: Good in O temper, moderate in H112 temper

Dimensional Stability: Good dimensional stability after forging and stress relief

Strength-to-Weight Ratio: Advantageous in applications requiring high strength and corrosion resistance

 

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)

Hardness testing (Brinell, multiple locations)

Impact testing (Charpy V-notch, especially for cryogenic applications)

Fatigue testing (as required)

Nondestructive Testing:

Ultrasonic inspection (100% volumetric, per ASTM B594/E2375, or AMS 2630)

Eddy current testing (surface and near-surface defects)

Penetrant inspection (surface defects)

Radiographic testing (internal macroscopic defects)

Microstructural Analysis:

Grain size determination

Precipitate and intermetallic compound evaluation

Grain flow pattern verification

Stress corrosion sensitivity testing

Dimensional Inspection:

CMM (Coordinate Measuring Machine) verification

Outer diameter, inner diameter, wall thickness, height, flatness, concentricity, etc.

Standard Certifications:

Material 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-5083/5A06, etc.

 

Primary Applications:

Marine Industry:

Shipbuilding and yacht construction (hull structures, deck equipment, seawater piping)

Offshore drilling platform structural components

Desalination equipment

Submarine components

Cryogenic Engineering:

Liquefied Natural Gas (LNG) storage tanks and transfer pipeline rings

Cryogenic equipment components

Pressure Vessels:

Medium to high-pressure vessel flanges and rings

Pressure-bearing equipment components

Nuclear Industry:

Nuclear reactor cooling system components

Radiation shielding structures

Rail Transit:

High-speed train body structural components

Design Advantages:

Excellent corrosion resistance, especially in marine and industrial environments, with very high resistance to seawater corrosion

Superior weldability, with high weld strength and good ductility

Exceptional cryogenic toughness, with improved properties at extremely low temperatures

Moderate strength and good ductility, suitable for structural components

Forging process optimizes grain flow and internal quality

Excellent resistance to stress corrosion cracking and exfoliation corrosion

Lightweight, contributing to energy savings and emission reduction

Non-magnetic

Design Limitations:

Cannot be strengthened by heat treatment; strength limit is lower than 2xxx and 7xxx series high-strength alloys

Long-term use above 65°C may lead to sensitization (due to Mg₂Al₃ phase precipitation), increasing susceptibility to stress corrosion. Operating temperature needs to be controlled or H321 temper chosen.

Strength level is lower than 5083’s H116/H321 tempers, but may perform better in specific corrosive environments.

Relatively higher cost.

Economic Considerations:

High-performance material, higher initial cost but long lifespan and low maintenance costs

Excellent corrosion resistance reduces long-term protection needs

Good weldability lowers the cost of fabricating complex structures

Lightweight properties help reduce transportation fuel costs

Sustainability Aspects:

100% recyclable with high resource utilization efficiency

Aluminum production processes are becoming increasingly environmentally friendly, with reduced energy consumption

Long service life reduces waste generation

Material Selection Guidance:

Choose 5A06 H112 forged rings when high strength, exceptional corrosion resistance (especially to seawater), excellent weldability, and cryogenic properties are required, and the upper limit of strength is not as critical as for 7075/7050.

For structures serving long-term at temperatures above 65°C, H321 temper should be selected, or other alloys considered.

Suitable for critical applications in marine, cryogenic, and nuclear industries as structural and pressure-bearing components.