Copper Alloy C91700-M07
Heat-treated state
UNS C91700
M07 = as continuous cast
Continuous-cast bar/tube stock for machined gear blanks and bearings; finest grain and highest as-cast strength, slightly lower ductility.
Values for the M07 condition
Other C91700 tempers and conditions
C91700 is listed in 4 conditions; see the grade overview at C91700.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M01Default As sand cast | Standard condition for gear rims, worm wheels and housings poured in sand moulds; most widely stocked/produced form. | 172 | 310 | 12 | 95 HB | 9 % IACS |
As plaster cast | Permanent-mold pouring for repeat-run small gear blanks and bushings; finer structure and better surface than sand casting. | 190 | 325 | 10 | 100 HB | 9 % IACS |
As centrifugally cast | Choose for worm-wheel rims, bushings and rings where a dense, porosity-free wall and higher strength are required. | 193 | 331 | 10 | 100 HB | 9 % IACS |
M07This page As continuous cast | Continuous-cast bar/tube stock for machined gear blanks and bearings; finest grain and highest as-cast strength, slightly lower ductility. | 207 | 345 | 8 | 105 HB | 9 % IACS |
What is C91700-M07?
C91700-M07 is C91700 heat treated to M07 — continuous-cast bar/tube stock for machined gear blanks and bearings; finest grain and highest as-cast strength, slightly lower ductility. C91700-M07 has a yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 112 GPa (16.2 Msi). C91700-M07 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 854°C (1,569 °F). M01 is the default condition FabDigit quotes; M07 is available on request or by drawing note.
Advantages
- High service temperature — 260°C (500 °F), better than 75% of copper alloy grades
Limitations
- Limited ductility — 8%, worse than 83% of copper alloy grades
- Low electrical conductivity — 9 % IACS, worse than 78% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C91700-M07 properties
Typical room-temperature values for C91700-M07; 20 are specific to this condition. Other listed values are C91700 reference data and may not represent this condition. Bars are the position among copper alloy grades.
Physical3
C91700-M07 has a density of 8.8 g/cm³ (0.318 lb/in³), heavier than 58% of copper alloy grades. It melts at 854°C (1,569 °F).
Mechanical15
C91700-M07 has a yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Elongation at break is 8% and the elastic modulus is 112 GPa (16.2 Msi).
Thermal6
C91700-M07 is rated for continuous service to 260°C (500 °F). It conducts heat at 47 W/m·K (27.2 BTU/hr·ft·°F), worse than 69% of copper alloy grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
C91700-M07 conducts electricity at 9 % IACS, worse than 78% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (64/100), better than 52% of copper alloy grades.
Sustainability4
Producing a kilogram of C91700-M07 takes about 62 MJ of energy and emits 4.2 kg of CO₂ — more than 76% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C91700-M07's machinability is fair (37/100, better than 55% of copper alloy grades); weldability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with C91700-M07
Is C91700 easy to machine?
Machinability ≈20 % of free-cutting brass — take positive-rake sharp carbide tooling, moderate speed with generous coolant; gummy chips and hard tin-rich phases cause built-up edge.
Can C91700 be welded?
Essentially not arc-weldable for structural joints; repair only by low-heat braze or tin-bronze TIG with preheat and slow cool, expect hot-shortness and porosity.
Can C91700 be formed, bent or molded?
Casting alloy only, no cold forming; long freezing range demands chills, generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
What surface finishes work on C91700?
Cannot be anodised; finish by machining/grinding, polishing, chemical patination, or tin/nickel electroplating; lacquer to prevent tarnish in display parts.
C91700 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 |
|---|---|---|
| Sn | 11.3 – 12.5 | 12 |
| NiNi + Co | 1.2 – 2 | 1.6 |
| Pb | ≤ 0.25 | — |
| Zn | ≤ 0.25 | — |
| Fe | ≤ 0.15 | — |
| Sb | ≤ 0.2 | — |
| Pmax (deoxidiser) | ≤ 0.3 | — |
| S | ≤ 0.05 | — |
| Al | ≤ 0.01 | — |
| Si | ≤ 0.01 | — |
| Cu | ≥ 84.5 (balance) | — |
C91700-M07 — frequently asked
What is C91700-M07 used for?
C91700-M07 is typically used for heavy-duty worm gears, worm wheel rims, gear blanks, high-load bearing bushings, wear rings and wear pads and thrust bearings for slow-speed drives. In short: high-nickel gear bronze; most ductile tin gear bronze; cast-only, hard to machine.
What is the yield strength of C91700-M07?
C91700-M07 has a typical yield strength of 207 MPa (30 ksi) and a tensile strength of 345 MPa (50 ksi) — weaker than 52% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is C91700-M07 easy to machine?
Not especially — machinability is rated fair (37/100, better than 55% of copper alloy grades). Machinability ≈20 % of free-cutting brass — take positive-rake sharp carbide tooling, moderate speed with generous coolant; gummy chips and hard tin-rich phases cause built-up edge.
Can C91700-M07 be welded?
Not readily — weldability is rated poor (25/100). Essentially not arc-weldable for structural joints; repair only by low-heat braze or tin-bronze TIG with preheat and slow cool, expect hot-shortness and porosity.
What surface finishes work on C91700-M07?
Cannot be anodised; finish by machining/grinding, polishing, chemical patination, or tin/nickel electroplating; lacquer to prevent tarnish in display parts.
Can C91700-M07 be formed, bent or molded?
Casting alloy only, no cold forming; long freezing range demands chills, generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
What is the maximum service temperature of C91700-M07?
C91700-M07 is rated for continuous use to about 260°C (500 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C91700-M01 and C91700-M07?
M01 is the default condition — standard condition for gear rims, worm wheels and housings poured in sand moulds; most widely stocked/produced form. M07: continuous-cast bar/tube stock for machined gear blanks and bearings; finest grain and highest as-cast strength, slightly lower ductility. Yield strength is 172 MPa in M01 versus 207 MPa in M07.
Sources
- ASTM B427 — Gear Bronze Alloy Castings — ASTM International (2020)
- ASTM B505/B505M — Continuous Cast Copper Alloy Castings — ASTM International (2018)
- CDA Alloy Database — C91700 — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- GB/T 1176 (ZCuSn12Ni2) — SAC (2013)
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.