CuNi3Si — C70320
CuNi3Si – UNS.C70320 Nickel Silicon Bronze Alloys, which is an age-hardening alloy, higher alloyed in comparison with CuNi2Si
CuNi3Si — C70320
CuNi3Si – UNS.C70320 Nickel Silicon Bronze Alloys, which is an age-hardening alloy, higher alloyed in comparison with CuNi2Si, has higher contents of nickel and silicon in order to be able to adjust a particularly higher strength. It has an a-structure with very fine precipitations and recommends itself both for lead frames which require a high rigidity of the pins and for connector with high demands on the electrical conductivity, strength and relaxation behavior.

Where C70320 Is Used
Typical end uses published by Vital for this grade.
Electrical
Resistance Welding Electrodes, Motor Rotor Bar, And Resistance Welding Tips.
Fastener
Fastener parts
Industrial
Brazing Rod, Welding Rod
Specifications And Material Data
| Ni | 2.50-3.50% |
|---|---|
| Si | 0.60-1.10% |
| Fe | 0.10% Max. |
| Zn | 0.50% Max. |
| Cu | Balance |
Copper plus additions equal 99.50% minimum.
| Specific Gravity | 8.80-8.90 g/cm3 |
|---|---|
| Coefficient of Thermal Expansion per °C | 17 x 10-6 /K (20-300°C) |
| Electrical Conductivity (% IACS) | 38 (22 Ms/m) |
| Thermal Conductivity (W/mk) | 190 |
| Modulus of Elasticity (10 3 MPA) | 135 |
1). the units are based upon US Customary. 2). the typical physical properties apply to age hardened products.
Sizes And Product Forms
Available Sizes
Custom Diameter & Sizes, Random Mill lengths
Available Products And Forms
Round bars, Flat bars, Square bars, Rectangular bars, Hexagon bars
Custom shapes are available upon request.
International Specification
| Rods/Bars/Plates/Sheets | UNS.C70320, RWMA Class 3 |
|---|---|
| European Standards | CuNi3Si, DIN 2.0855, CW112C to EN |
Unless otherwise specified, material will be produced to DIN & RWMA.
Abbreviations
- ASTM — American Society for Testing and Materials
- RWMA — Resistance Welder Manufacturers' Association
Tempers And Mechanical Data
The detailed Mechanical Properties will be available on request from customers.
Frequently Asked Questions
Answers drawn from the Vital technical data for this page.
What is the chemical composition of C70320?
C70320 is supplied to the following nominal composition:
- Ni: 2.50-3.50%
- Si: 0.60-1.10%
- Fe: 0.10% Max.
- Zn: 0.50% Max.
- Cu: Balance
What are the typical physical properties of C70320?
Typical values published by Vital for C70320:
- Specific Gravity: 8.80-8.90 g/cm3
- Coefficient of Thermal Expansion per °C: 17 x 10-6 /K (20-300°C)
- Electrical Conductivity (% IACS): 38 (22 Ms/m)
- Thermal Conductivity (W/mk): 190
- Modulus of Elasticity (10 3 MPA): 135
Which international specifications does C70320 meet?
- Rods/Bars/Plates/Sheets: UNS.C70320, RWMA Class 3
- European Standards: CuNi3Si, DIN 2.0855, CW112C to EN
Can you supply mechanical property data for C70320?
The detailed Mechanical Properties will be available on request from customers.
Which product forms and sizes are available?
Custom Diameter & Sizes, Random Mill lengths Round bars, Flat bars, Square bars, Rectangular bars, Hexagon bars Custom shapes are available upon request.
How do I request a quotation?
Email the grade, temper, dimensions and quantity to [email protected]. Unless otherwise specified, material is produced to ASTM.
Quote C70320 To Your Specification
Send grade, temper, dimensions and quantity. Custom shapes are available on request.






