Copper Alloy AlBC4-TQ50
Supply condition
GB AlBC4
TQ50 = temper annealed 675 °C / 6 h, air cooled
Specify for thick-section seawater parts: breaks up continuous κIII/β' networks and greatly reduces selective-phase (de-aluminification) attack.
Values for the TQ50 condition
Other AlBC4 tempers and conditions
AlBC4 is listed in 4 conditions; see the grade overview at AlBC4.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
TQ50This page Temper annealed 675 °C / 6 h, air cooled | Specify for thick-section seawater parts: breaks up continuous κIII/β' networks and greatly reduces selective-phase (de-aluminification) attack. | 265 | 605 | 23 | 152 HB | 7.3 % IACS |
FDefault As fabricated | Standard stocked condition for propellers, pump casings and valve bodies; use when full heat treatment is not specified. | 275 | 620 | 20 | 159 HB | — |
Centrifugally cast, as-cast | Pick for rings, bushings, sleeves and pump wear parts where the denser, finer centrifugal structure gives higher strength and soundness. | 290 | 655 | 20 | 165 HB | 7.1 % IACS |
As-welded deposit | Properties of matching-filler (ERCuNiAl) repair welds and weld-overlaid areas before any post-weld temper anneal. | 290 | 600 | 16 | 170 HB | 7 % IACS |
What is AlBC4-TQ50?
AlBC4-TQ50 is AlBC4 supplied in the TQ50 condition — specify for thick-section seawater parts: breaks up continuous κIII/β' networks and greatly reduces selective-phase (de-aluminification) attack. AlBC4-TQ50 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 605 MPa (87.7 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 23% and the elastic modulus is 117 GPa (17 Msi). AlBC4-TQ50 has a density of 7.64 g/cm³ (0.276 lb/in³), lighter than 92% of copper alloy grades. It melts at 1,043°C (1,909 °F). F is the default condition FabDigit quotes; TQ50 is available on request or by drawing note.
Advantages
- Good corrosion resistance — 84/100, better than 100% of copper alloy grades
- Lightweight — 7.64 g/cm³ (0.276 lb/in³), better than 92% of copper alloy grades
- Readily welded — 75/100, better than 89% of copper alloy grades
- Tough — resists crack growth — 55 MPa·√m (50.1 ksi·√in), better than 85% of copper alloy grades
- High service temperature — 300°C (572 °F), better than 85% of copper alloy grades
Limitations
- Low electrical conductivity — 7.3 % IACS, worse than 84% of copper alloy grades
- Poor heat conductor — 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 80% of copper alloy grades
AlBC4-TQ50 properties
Typical room-temperature values for AlBC4-TQ50; 22 are specific to this condition. Other listed values are AlBC4 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
AlBC4-TQ50 has a density of 7.64 g/cm³ (0.276 lb/in³), lighter than 92% of copper alloy grades. It melts at 1,043°C (1,909 °F).
Mechanical16
AlBC4-TQ50 has a yield strength of 265 MPa (38.4 ksi) and a tensile strength of 605 MPa (87.7 ksi) — stronger than 55% of copper alloy grades. Elongation at break is 23% and the elastic modulus is 117 GPa (17 Msi).
Thermal6
AlBC4-TQ50 is rated for continuous service to 300°C (572 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 80% of copper alloy grades. Thermal expansion is 16.2 µm/m·K (9 µin/in·°F).
Electrical3
AlBC4-TQ50 conducts electricity at 7.3 % IACS, worse than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (84/100), better than 100% of copper alloy grades.
Sustainability4
Producing a kilogram of AlBC4-TQ50 takes about 55 MJ of energy and emits 4.2 kg of CO₂ — less than 72% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
AlBC4-TQ50's machinability is poor (34/100, worse than 53% of copper alloy grades); weldability very good (75/100); formability poor (28/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AlBC4-TQ50
Is AlBC4 easy to machine?
Tough and gummy — use sharp positive-rake carbide, rigid setups, moderate speed (60–110 m/min) with generous feed and coolant; chips are stringy, so chip-breaking geometry helps.
Can AlBC4 be welded?
Readily GTAW/GMAW welded with matching ERCuNiAl filler under argon; clean off the Al₂O₃ film, preheat ≤150 °C on heavy sections and consider a 675 °C temper anneal after major repairs.
Can AlBC4 be formed, bent or molded?
Sand, centrifugal and continuous casting only; needs oxide-free bottom filling, chills and ample risering because of the short freezing range and high shrinkage.
What surface finishes work on AlBC4?
Takes a fine machined and polished finish and develops a protective olive-brown seawater film; not anodizable, difficult to solder/braze, and electroplating requires special activation of the aluminium oxide layer.
AlBC4 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Al | 8.5 – 9.5 | 9 |
| NiNi + Co basis; Ni must be ≥ Fe | 4 – 5 | 4.5 |
| FeFe content shall not exceed Ni content | 3.5 – 4.5 | 4 |
| Mn | 0.8 – 1.5 | 1.1 |
| Si | ≤ 0.1 | 0.05 |
| Pb | ≤ 0.03 | 0.01 |
| CuRemainder; JIS CAC704 permits a wider Cu window than ASTM C95800 | ≥ 79 (balance) | — |
AlBC4-TQ50 — frequently asked
What is AlBC4-TQ50 used for?
AlBC4-TQ50 is typically used for propellers, pump housings and offshore hardware. In short: weldable nickel-aluminium bronze; marine propeller standard; best seawater cast bronze.
What is the yield strength of AlBC4-TQ50?
AlBC4-TQ50 has a typical yield strength of 265 MPa (38.4 ksi) and a tensile strength of 605 MPa (87.7 ksi) — stronger than 55% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is AlBC4-TQ50 easy to machine?
Not especially — machinability is rated poor (34/100, worse than 53% of copper alloy grades). Tough and gummy — use sharp positive-rake carbide, rigid setups, moderate speed (60–110 m/min) with generous feed and coolant; chips are stringy, so chip-breaking geometry helps.
Can AlBC4-TQ50 be welded?
Yes — weldability is rated very good (75/100). Readily GTAW/GMAW welded with matching ERCuNiAl filler under argon; clean off the Al₂O₃ film, preheat ≤150 °C on heavy sections and consider a 675 °C temper anneal after major repairs.
What surface finishes work on AlBC4-TQ50?
Takes a fine machined and polished finish and develops a protective olive-brown seawater film; not anodizable, difficult to solder/braze, and electroplating requires special activation of the aluminium oxide layer.
Can AlBC4-TQ50 be formed, bent or molded?
Sand, centrifugal and continuous casting only; needs oxide-free bottom filling, chills and ample risering because of the short freezing range and high shrinkage.
What is the maximum service temperature of AlBC4-TQ50?
AlBC4-TQ50 is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AlBC4-F and AlBC4-CF?
F is the default condition — standard stocked condition for propellers, pump casings and valve bodies; use when full heat treatment is not specified. CF: pick for rings, bushings, sleeves and pump wear parts where the denser, finer centrifugal structure gives higher strength and soundness. Yield strength is 275 MPa in F versus 290 MPa in CF.
Sources
- JIS H5120 Copper alloy castings (CAC704 / AlBC4) — Japanese Standards Association (2016)
- ASTM B148 Standard Specification for Aluminum-Bronze Sand Castings (C95800) — ASTM International (2018)
- ASTM B505/B505M Continuous Cast Copper Alloys — ASTM International (2018)
- CDA Alloy Datasheet C95800 (nickel-aluminum bronze) — Copper Development Association (2023)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Nickel Aluminium Bronze for Seawater Service — Copper Development Association UK (2016)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.