Copper Alloy C91100
UNS C91100
C91100 is a high-tin cast bronze from the C90000–C95999 family, historically designated Alloy B, hardened by the tin-rich delta phase.
Reference datasheet — C91100 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the M01 condition
C91100 tempers and conditions
C91100 is supplied in 4 conditions, soft to hard. M01 is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
M01Default As sand cast | Standard as-cast sand-mould condition for worm gear rims, bearing blanks and bridge plates. | 172 | 241 | 2 | 135 HB | 8 % IACS |
As pressure die cast | Used for smaller repeat parts where mould-chilled fine structure and better surface are wanted. | 180 | 255 | 2 | 140 HB | 8 % IACS |
As centrifugally cast | Choose for rings, bushings and gear blanks needing sounder, finer structure than sand casting. | 186 | 262 | 2 | 140 HB | 8 % IACS |
As continuous cast | Continuous-cast bar/tube stock for machined bushings and worm gears; densest and most uniform product form. | 193 | 275 | 2 | 145 HB | 8 % IACS |
What is C91100?
C91100 is a high-tin cast bronze from the C90000–C95999 family, historically designated Alloy B, hardened by the tin-rich delta phase. Engineers specify it for worm gearing and slow-speed wear surfaces where 135 HB hardness and load capacity matter more than ductility, and it is supplied as sand, permanent-mold, centrifugal and continuous castings. Elongation is only 2 % at 241 MPa tensile and 172 MPa yield, so the alloy is notch-sensitive, unsuitable for shock loading and not fusion weldable; maximum service temperature is 260 °C. C91600 or C91700 nickel-bearing tin bronzes are the nearest alternatives when more toughness is needed. C91100 has a density of 8.6 g/cm³ (0.311 lb/in³), lighter than 59% of copper alloy grades. It melts at 830°C (1,526 °F). C91100 has a yield strength of 172 MPa (24.9 ksi) and a tensile strength of 241 MPa (35 ksi) — weaker than 60% of copper alloy grades. Elongation at break is 2% and the elastic modulus is 103 GPa (14.9 Msi).
What is C91100 used for?
- Worm gear rims for slow-speed drives
- Gear wheels
- Heavily loaded bearing bushings
- Wear plates and slide guides
- Thrust washers
- Machine tool nuts and screw threads
Advantages
- High service temperature — 260°C (500 °F), better than 75% of copper alloy grades
Limitations
- Limited ductility — 2%, worse than 98% of copper alloy grades
- Limited formability — 5/100, worse than 98% of copper alloy grades
- Difficult to weld — 15/100, worse than 94% of copper alloy grades
- High embodied carbon — 5.6 kg CO₂/kg, worse than 91% of copper alloy grades
- Poor heat conductor — 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 85% of copper alloy grades
C91100 properties
Typical room-temperature values for C91100-M01; bars are the position among copper alloy grades.
Physical3
C91100 has a density of 8.6 g/cm³ (0.311 lb/in³), lighter than 59% of copper alloy grades. It melts at 830°C (1,526 °F).
Mechanical15
C91100 has a yield strength of 172 MPa (24.9 ksi) and a tensile strength of 241 MPa (35 ksi) — weaker than 60% of copper alloy grades. Elongation at break is 2% and the elastic modulus is 103 GPa (14.9 Msi).
Thermal5
C91100 is rated for continuous service to 260°C (500 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 85% of copper alloy grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
C91100 conducts electricity at 8 % IACS, worse than 81% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 68% of copper alloy grades.
Sustainability4
Producing a kilogram of C91100 takes about 87 MJ of energy and emits 5.6 kg of CO₂ — more than 92% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C91100's machinability is fair (45/100, better than 64% of copper alloy grades); weldability poor (15/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C91100 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C91100
Is C91100 easy to machine?
Machines with short brittle chips; use sharp positive-rake carbide, rigid setup, light feeds and generous coolant — hard δ-phase abrades tooling and edges chip easily.
Can C91100 be welded?
Fusion welding is not recommended (hot-short, crack-prone); repair by brazing or soldering, or by low-heat braze-welding with matching tin-bronze rod.
Can C91100 be formed, bent or molded?
Cast product only — no cold or hot working; design generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
C91100 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 | 15 – 17 | 16 |
| Pdeoxidizer; raises hardness | ≤ 1 | 0.3 |
| Ni | ≤ 0.5 | |
| Pb | ≤ 0.25 | |
| Zn | ≤ 0.25 | |
| Fe | ≤ 0.25 | |
| Sb | ≤ 0.2 | |
| S | ≤ 0.05 | |
| Al | ≤ 0.01 | |
| Si | ≤ 0.01 | |
| Cu | ≥ 82 (balance) |
What surface finishes work on C91100?
Takes a good buffed or lapped finish; can be tin, nickel or chrome plated after cleaning, and gear/bearing surfaces are usually finish-ground or honed rather than coated.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C91100 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Alloy B
How much does C91100 cost?
C91100 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C91100 — frequently asked
What is C91100 used for?
C91100 is typically used for worm gear rims for slow-speed drives, gear wheels, heavily loaded bearing bushings, wear plates and slide guides, thrust washers and machine tool nuts and screw threads. In short: hardest plain tin bronze; cast worm-gear standard; very low ductility.
What is the yield strength of C91100?
C91100 has a typical yield strength of 172 MPa (24.9 ksi) and a tensile strength of 241 MPa (35 ksi) — weaker than 60% of copper alloy grades. Strength varies by condition: see the 4 listed tempers.
Is C91100 easy to machine?
Reasonably — machinability is rated fair (45/100, better than 64% of copper alloy grades). Machines with short brittle chips; use sharp positive-rake carbide, rigid setup, light feeds and generous coolant — hard δ-phase abrades tooling and edges chip easily.
Can C91100 be welded?
Not readily — weldability is rated poor (15/100). Fusion welding is not recommended (hot-short, crack-prone); repair by brazing or soldering, or by low-heat braze-welding with matching tin-bronze rod.
What surface finishes work on C91100?
Takes a good buffed or lapped finish; can be tin, nickel or chrome plated after cleaning, and gear/bearing surfaces are usually finish-ground or honed rather than coated.
Can C91100 be formed, bent or molded?
Cast product only — no cold or hot working; design generous risers and directional solidification to avoid tin sweat and interdendritic shrinkage.
What is the maximum service temperature of C91100?
C91100 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 C91100-M01 and C91100-M07?
M01 is the default condition — standard as-cast sand-mould condition for worm gear rims, bearing blanks and bridge plates. M07: continuous-cast bar/tube stock for machined bushings and worm gears; densest and most uniform product form. Yield strength is 172 MPa in M01 versus 193 MPa in M07.
How much does C91100 cost?
C91100 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B22 — Bronze Castings for Bridges and Turntables — ASTM International (2017)
- ASTM B505/B505M — Continuous-Cast Copper Alloy Castings — ASTM International (2018)
- CDA Copper Alloy Datasheet C91100 — Copper Development Association (copper.org) (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.18 — Friction, Lubrication and Wear Technology — ASM International (2017)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.