Copper Alloy C69700
UNS C69700
C69700 is a leaded copper-zinc-silicon brass developed to raise machinability while keeping the strength and corrosion resistance of the silicon brass family.
Reference datasheet — C69700 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 M20 condition
C69700 tempers and conditions
C69700 is supplied in 6 conditions, soft to hard. M20 is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Soft annealed | Pick when maximum ductility for bending, riveting or secondary forming is needed. | 170 | 415 | 38 | 85 HB | — |
M20Default As hot rolled | Standard stocked condition for extruded rod and bar destined for machining or forging. | 240 | 485 | 28 | 120 HB | — |
As hot extruded | Condition of finished hot forgings (valve bodies, stems) with no subsequent cold work. | 255 | 500 | 25 | 128 HB | 6.5 % IACS |
Quarter hard | Light cold draw for better straightness, surface finish and moderate strength increase on rod. | 380 | 550 | 18 | 150 HB | — |
Half hard | Use where higher yield strength and good chip control on automatic lathes are required. | 450 | 620 | 12 | 170 HB | — |
Full hard | Maximum strength/wear resistance for stems and shafts; ductility and further forming are limited. | 520 | 690 | 8 | 185 HB | — |
What is C69700?
C69700 is a leaded copper-zinc-silicon brass developed to raise machinability while keeping the strength and corrosion resistance of the silicon brass family. The default condition gives 485 MPa tensile, 240 MPa yield, 28 % elongation and 120 HB (68 HRB), with service to 200 °C and a machinability score of 72, which suits screw-machine plumbing and valve parts; tempers on file run O60, M20, M30, H01, H02 and H04. The lead content rules out fusion welding and cold formability is only moderate (score 45). Choose lead-free C69430 when the joint must be welded or lead is restricted. C69700 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F). C69700 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 52% of copper alloy grades. Elongation at break is 28% and the elastic modulus is 105 GPa (15.2 Msi).
What is C69700 used for?
- machined plumbing components
- valve parts
- hardware fittings
Advantages
- Low embodied carbon — 2.9 kg CO₂/kg, better than 99% of copper alloy grades
- Easy to machine — 72/100, better than 79% of copper alloy grades
Limitations
- Low electrical conductivity — 6.5 % IACS, worse than 91% of copper alloy grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
C69700 properties
Typical room-temperature values for C69700-M20; bars are the position among copper alloy grades.
Physical3
C69700 has a density of 8.3 g/cm³ (0.3 lb/in³), lighter than 80% of copper alloy grades. It melts at 820°C (1,508 °F).
Mechanical12
C69700 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 52% of copper alloy grades. Elongation at break is 28% and the elastic modulus is 105 GPa (15.2 Msi).
Thermal6
C69700 is rated for continuous service to 200°C (392 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 89% of copper alloy grades. Thermal expansion is 20.5 µm/m·K (11.4 µin/in·°F).
Electrical3
C69700 conducts electricity at 6.5 % IACS, worse than 91% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 57% of copper alloy grades.
Sustainability4
Producing a kilogram of C69700 takes about 45 MJ of energy and emits 2.9 kg of CO₂ — less than 97% of copper alloy grades. Typical recycled content is 40%.
Manufacturability7
C69700's machinability is very good (72/100, better than 79% of copper alloy grades); weldability poor (25/100); formability fair (45/100).
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. C69700 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C69700
Is C69700 easy to machine?
Machines well for a silicon brass thanks to the lead: use sharp positive-rake carbide, high speed, light feeds and copious coolant; chips are shorter than lead-free silicon brass but longer than C36000.
Can C69700 be welded?
Not recommended for fusion welding — lead promotes hot cracking and porosity; join by soft soldering or silver brazing with low heat input, or use mechanical joints.
Can C69700 be formed, bent or molded?
Excellent hot workability (extrusion/forging around 650–780 °C); cold formability is only moderate, so anneal between heavy bending or heading operations.
C69700 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 |
|---|---|---|
| Cu | 75 – 80 | 77.5 |
| Sisolid-solution strengthener; improves dezincification resistance | 2.5 – 3.5 | 3 |
| Pbfree-machining addition | 0.5 – 1.5 | 1 |
| Fe | ≤ 0.2 | |
| Znremainder, nominally ~18–19% | balance |
What surface finishes work on C69700?
Polishes to a bright golden finish and takes nickel, chrome or tin plating readily; not anodizable, so use lacquer or patina for decorative parts.
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).
How much does C69700 cost?
C69700 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.
C69700 — frequently asked
What is C69700 used for?
C69700 is typically used for machined plumbing components, valve parts and hardware fittings. In short: free-machining silicon brass; service to 200 °C; machines faster than C69430.
What is the yield strength of C69700?
C69700 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 485 MPa (70.3 ksi) — stronger than 52% of copper alloy grades. Strength varies by condition: see the 6 listed tempers.
Is C69700 easy to machine?
Yes — machinability is rated very good (72/100, better than 79% of copper alloy grades). Machines well for a silicon brass thanks to the lead: use sharp positive-rake carbide, high speed, light feeds and copious coolant; chips are shorter than lead-free silicon brass but longer than C36000.
Can C69700 be welded?
Not readily — weldability is rated poor (25/100). Not recommended for fusion welding — lead promotes hot cracking and porosity; join by soft soldering or silver brazing with low heat input, or use mechanical joints.
What surface finishes work on C69700?
Polishes to a bright golden finish and takes nickel, chrome or tin plating readily; not anodizable, so use lacquer or patina for decorative parts.
Can C69700 be formed, bent or molded?
Excellent hot workability (extrusion/forging around 650–780 °C); cold formability is only moderate, so anneal between heavy bending or heading operations.
What is the maximum service temperature of C69700?
C69700 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C69700-M20 and C69700-H04?
M20 is the default condition — standard stocked condition for extruded rod and bar destined for machining or forging. H04: maximum strength/wear resistance for stems and shafts; ductility and further forming are limited. Yield strength is 240 MPa in M20 versus 520 MPa in H04.
How much does C69700 cost?
C69700 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
- C69700 alloy datasheet (leaded silicon brass) — Copper Development Association (2023)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASTM B124 / B283 — Copper and copper-alloy forging rod, bar and shapes; die forgings — ASTM International (2020)
- ASM Handbook Vol.13B — Corrosion: Materials (copper alloys) — ASM International (2005)
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.