5052 H32 vs 6061 T6: How does post-processing process reshape the performance of aluminum alloy?

In the industrial application of aluminum alloy, the state code (such as H32, T6) is not only the "code" of performance, but also the key to determine whether the material can adapt to the scene. When engineers face the corrosion resistance requirements of ship decks and the high-strength challenges of aviation components, why do they compare and choose between 5052 H32 vs 6061 T6? What is the essential difference between cold working hardening and heat treatment strengthening? How do different treatment processes affect the strength, toughness and processing characteristics of materials? ​

This article will take two typical states as the starting point to dismantle the "semi-hard cold working magic" of 5052 H32 and the "aging strengthening secret" of 6061 T6, and reveal the technical logic behind the state code of aluminum alloy through comparative analysis of process principles, performance data, and application scenarios. Whether it is to solve the crack problem in complex forming or optimize the structural strength under dynamic load, reading this analysis will help you master the core rules of aluminum alloy post-processing and make the material performance accurately match industrial needs.

1.5052 H32 vs 6061 T6: What are their basic concepts and state codes?

(1) 5052 H32

1) Definition:

H32 is the work hardening state of aluminum-magnesium alloy (Al-Mg system), and its full name is "work hardening + stabilization annealing". Among them:

H represents work hardening;

3 represents "partial annealing after work hardening" (stabilization treatment);

2 represents the cold working amount of about 20% (such as cold rolling, cold drawing, etc.).

2) Process path:

After the raw materials are cold worked (such as rolling and stretching), they are annealed for a short time at 140-200℃ (stabilization treatment) to eliminate some internal stress and retain 50%~70% of the cold working strengthening effect.

3) Performance characteristics:

Tensile strength: 210-270MPa (semi-hard state);

Elongation: 12%-16%;

Hardness: 68HB (better than pure aluminum, lower than 6061 T6).

(2) 6061 T6

1) Definition:

T6 is the heat treatment strengthening state of aluminum-magnesium-silicon alloy (Al-Mg-Si system), the full name of which is "solution treatment + artificial aging". Among them:

T represents heat treatment;

6 represents artificial aging to peak strength.

2) Process path:

Solution treatment: heat the alloy to about 530℃ and keep it warm for 1-2 hours to completely dissolve the Mg₂Si strengthening phase;

Quenching: quickly cool to room temperature with water to form a supersaturated solid solution;

Artificial aging: keep it warm at 175-185℃ for 8-18 hours to promote the uniform precipitation of the Mg₂Si phase and improve the strength.

3) Performance characteristics:

Tensile strength: ≥310MPa;

Yield strength: ≥276MPa;

Hardness: 95HB (39% higher than 5052 H32).

2. Reasons for treatment: the underlying logic of performance improvement

(1) Why is 5052 treated with H32?

1) Non-heat-treatable strengthening characteristics:

5052 belongs to the Al-Mg alloy system. Magnesium cannot form a strengthening phase through heat treatment, and strength can only be improved through cold working. H32 treatment achieves a balance between strength and plasticity by controlling the amount of cold working (such as 20% deformation rate) and stabilization annealing. It is suitable for scenes that require medium strength and require bending and stretching (such as oil tanks and ship decks).

2) Corrosion resistance optimization:

Cold working enriches magnesium at the grain boundaries, forming a denser oxide film and improving salt spray resistance.

(2) Why is 6061 treated with T6?

1) Heat-treatable strengthening properties:

6061 contains magnesium (0.8-1.2%) and silicon (0.4-0.8%), which can form Mg₂Si strengthening phase. T6 treatment makes Mg₂Si phase precipitate uniformly at the nanometer level through solid solution + aging, and the strength is increased by more than 40%.

2) Comprehensive performance optimization:

Hardness improvement: T6 state hardness reaches 95HB, which is suitable for precision processing (such as CNC parts);

Fatigue resistance is enhanced: fatigue strength is about 140MPa, which is 1.4 times that of 5052 H32, suitable for bearing dynamic loads (such as automobile suspension parts).

3.5052 H32 vs 6061 T6: Differentiation in performance

(1) Game between strength and toughness

5052 H32: "Soft with hard" is achieved through cold processing, which is suitable for scenes that require frequent bending (such as automobile fuel tank stretch forming).

6061 T6: T6 treatment makes its tensile strength about 40% higher than 5052 H32, but the elongation decreases by 30%, and severe plastic deformation needs to be avoided.

(2) Environmental adaptability of corrosion resistance

5052 H32: The oxide film formed by magnesium has natural resistance to chloride ions (Cl⁻), and performs well in coastal areas or ship applications.

6061 T6: The copper content (0.15-0.4%) makes it prone to pitting in acidic or salt spray environments, and it needs to rely on anodizing (film thickness ≥ 15μm) to improve corrosion resistance.

(3) Cost and efficiency of processing technology

5052 H32: Low investment in cold processing equipment and short processing cycle (such as direct forming of cold rolled coils), suitable for mass production.

6061 T6: Heat treatment requires a high-temperature furnace and precise temperature control, and the processing cost increases by about 20%, but high strength and lightweight can be achieved through T6 treatment.

4.5052 H32 vs 6061 T6: Scenario-based application decision

(1) Scenarios where 5052 H32 is preferred

Marine engineering: ship decks, port equipment (resistant to salt spray corrosion);

Cryogenic containers: LNG storage tanks, refrigerated truck bodies (toughness remains at -40°C);

Complex forming: automobile fuel tanks, cooker drawing parts (excellent cold processing performance).

(2) Scenarios where 6061 T6 is preferred

Aerospace: wing ribs, seat frames (high strength and lightweight);

New energy vehicles: battery pack housings, motor brackets (impact resistance and heat dissipation required);

Precision machinery: industrial robot joints, automation equipment guide rails (high hardness and dimensional stability).

(3) Substitution and complementary strategies

1) Substitution options:

If higher strength is required, 6061 T6 can replace 5052 H32 (such as upgrading ship guardrails to 6061 T6 extruded profiles);

If excellent corrosion resistance is required, 5052 H32 can replace some stainless steel (such as 304) to reduce costs.

2) Composite applications:

Structural parts use 6061 T6 (high strength), and external protective parts use 5052 H32 (corrosion resistance), such as the combination of automobile chassis frame and fuel tank.

5. Notes: Performance shortcomings and process traps

(1) Limitations of 5052 H32

Poor hot workability: Heating to above 300℃ will cause coarse grains, which is not suitable for forging or hot rolling;

Cutting is easy to stick to the tool: Coated tools (such as TiAlN coatings) are required, and the cutting speed is controlled below 1500rpm.

(2) Risk points of 6061 T6

Welding cracks: ER5356 welding wire is required, and the welding speed is controlled to ≤200mm/min. Annealing (340℃×1h) is required after welding to eliminate stress;

Stress corrosion: In a Cl⁻-containing environment, T6 state is more prone to intergranular corrosion than H32 state. It is recommended to use T73 overaging treatment.

(3) Details of state selection

5052: H32 (semi-hard) or H112 (state after hot working) are commonly used, and H36/H38 (too hard to cause brittleness) should be avoided;

6061: T6 is suitable for structural parts, T651 (stress relief) is suitable for machining, and T4 (natural aging) is suitable for parts that require subsequent forming.

6.5052 H32 vs 6061 T6: Performance summary and decision-making suggestions

Decision tree suggestions:

If corrosion resistance + formability is required, choose 5052 H32;

If high strength + processing accuracy is required, choose 6061 T6;

If corrosion resistance + high strength is required, consider 5083 H116 (Al-Mg system, tensile strength ≥310MPa) or 6061 T6 + anodizing;

If cost-sensitive, 5052 H32 is about 10% cheaper than 6061 T6 (difference in raw material cost).

Through the above analysis, a scientific choice can be made between 5052 H32 and 6061 T6 based on the core requirements of specific application scenarios to avoid cost waste caused by excess or insufficient performance.