C61400
C61400 is an Al-Fe-Mn strengthened Al-bronze alloy (Cu-Al-Fe-Mn multicomponent system). With the synergistic advantage of “corrosion resistance × wear resistance × medium and high strength”, it can replace common copper alloy and stainless steel in marine, chemical and mechanical fields. The following is systematically analyzed from six dimensions:
I. Standard System and Brand Code
1. Core implementation standards
- International mainstream: ASTM B150 (American standard, which regulates the processing of aluminum bronze bars, plates, forgings, etc., including composition, performance and flaw detection requirements), and derived standards include ASTM B169 (seamless pipe) and ASTM B608 (forgings);
- Domestic adaptation: there is no completely equivalent brand, and the composition of QAl11-6-6 in GB/T 5231 is similar (but the aluminum content of C61400 is lower, ranging from 6.0% to 8.0%).
2. Business and Alias
- American standard UNS logo: UNS C61400；;
- Commonly known as “6-3 aluminum bronze” (simplifying the expression of Al 6-8% and Fe 1.5-3.5%), it belongs to the subclass of high aluminum aluminum bronze.
II. Chemical composition (mass fraction%, ASTM B150 standard)
Through the design of “Al solid solution+Fe precipitation strengthening”, C61400 has precise elements:
| Element | Content range | Core role |
|---|---|---|
| Cu + Ag | 88.0 – 92.5 | Matrix, providing electrical conductivity, plasticity and basic corrosion resistance |
| Al | 6.0 – 8.0 | Forming β phase (AlCu₃), strengthening the matrix and improving hardness and wear resistance |
| Fe | 1.5 – 3.5 | Refining grains, precipitating Fe – Al intermetallic compounds (κ phase), significantly enhancing high – temperature strength and wear resistance |
| Mn | ≤ 1.0 | Enhancing oxidation resistance and sulfidation corrosion resistance |
| Zn/Pb/P | ≤ 0.20/≤ 0.01/≤ 0.015 | Strictly controlling impurities, reducing hot brittleness, and optimizing casting / cutting performance |
III. Mechanical properties (by processing state)
The performance of C61400 is far superior to that of ordinary aluminum bronze (such as C61000) because of the κ phase precipitated by hot working and aging;
| State | Tensile strength (MPa) | Yield strength (MPa) | Elongation (%) | Hardness (HB) | Core characteristics |
|---|---|---|---|---|---|
| Annealed state | 530 – 600 | 275 – 400 | ≥ 25 | 120 – 180 | Easy to process (cutting, welding) |
| Cold – worked state | 700 – 800 | 400 – 600 | 8 – 15 | 180 – 220 | High strength (suitable for high – stress scenarios) |
| Age – strengthened state | 800 – 900 | 500 – 650 | 5 – 10 | 220 – 250 | High wear resistance (bearings, gears) |
Auxiliary features:
- Impact toughness: impact energy at room temperature ≥40 J, and still ≥30 J at -40℃ (excellent low-temperature toughness, suitable for polar/cryogenic environment);
- Corrosion resistance: the corrosion rate in 3.5% NaCl solution is ≤0.02 mm/year (better than 316L stainless steel), and it has strong biological fouling resistance.
IV. Requirements for Heat Treatment and Processing
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Hot working (core advantage, easy forming):
- Temperature: initial forging 850~900℃, final forging ≥650℃ (to avoid excessive precipitation of β phase and maintain plasticity);
- Advantages: excellent plasticity at high temperature, forging, extruding and rolling complex shapes (such as propeller and valve body).
-
Heat treatment process:
- Solution treatment: heat preservation at 750~850℃ and water cooling to homogenize α+β dual-phase structure and eliminate casting segregation;
- Annealing treatment: slow cooling at 500~650℃ to restore plasticity (convenient for subsequent cold working, such as cold rolling and spinning);
- Post-welding treatment: argon arc welding (TIG) uses ERCuAl-A2 welding wire, preheating at 200~250℃, and stress relief annealing at 550℃ after welding (to prevent cold cracks and restore corrosion resistance).
V. Main application fields (medium and high load+medium corrosion scenario)
Relying on “wear resistance × corrosion resistance × medium and high strength”, C61400 monopolizes the following fields (the performance is superior to that of ordinary copper alloys, and the cost is only one third of that of nickel-based alloys):
- Marine Engineering:
- Seawater systems: Condenser tube sheets, marine propeller shaft sleeves (resistant to seawater scouring + cavitation, service life is more than 3 times that of brass);
- Deep – sea equipment: Valve bodies, hydraulic joints (resistant to high – pressure corrosion at a water depth of 3000 meters, replacing titanium alloy to reduce costs by 50%).
- Chemical Industry and Energy:
- Corrosive media: Linings of chlor – alkali electrolyzers (resistant to wet chlorine corrosion), sulfuric acid/hydrochloric acid delivery pipelines (non – oxidizing acid environment);
- Heat exchangers: Tube – side design temperature ≤ 300°C, shell – side pressure ≤ 10 MPa (replacing stainless steel, improving corrosion resistance).
- Machinery Manufacturing:
- Wear – resistant components: Bearing cages, gear sleeves (surface hardness reaches 400 HB after quenching, resistant to abrasive wear);
- Aerospace: Landing gear bushings, hydraulic pump rotors (fatigue strength ≥ 250 MPa, stable for 10⁷ cycles).
- Special Scenarios:
- Cryogenic equipment: LNG pump valve sealing rings (impact toughness ≥ 25 J at – 162°C, resistant to low – temperature corrosion);
- Power transmission: High – voltage switch contacts (electrical conductivity ≥ 18% IACS, considering both electrical conductivity and corrosion resistance).
Key Summary
- Core Advantages:
- Performance balance: Its strength is twice that of ordinary brass, corrosion resistance is close to that of nickel – based alloys, and wear resistance exceeds that of tin bronze.
- Processing friendliness: It has excellent hot/cold workability, can be made into complex shapes, and reduces manufacturing costs.
- Low – temperature adaptability: It still maintains toughness at – 40°C, meeting the needs of polar and cryogenic engineering.
- Limitations:
- In strongly alkaline environments (such as concentrated NaOH), Al is prone to alkali corrosion and needs to be avoided.
- Cold work hardening is fast, and multiple annealing processes will increase the processing cost by 15 – 20%.
C61400 is the “benchmark of medium – strength corrosion – resistant aluminum bronze”. It breaks through the bottleneck of ordinary copper alloys through Al – Fe synergistic strengthening, and becomes the “first choice for copper alloy upgrading” in fields such as marine anti – corrosion, chemical wear resistance, and low – temperature transmission, redefining the material cost – performance ratio in medium and high – load scenarios.