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Copper-Nickel-Tin Strip (GMX96/GMX215)
- Special Metals
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Overview

Widely used to form contact springs, GMX96/GMX215 are core NGK products available as plates or strips. They offer an ideal combination of properties such as tensile strength, fatigue strength, thermal stability, bending formability, and corrosion resistance.
Features
High Performance Conductive Spring Material GMX96
NGK Copper-Nickel-Tin alloy "GMX96" is an age hardening type copper alloy, using spinodal decomposition. GMX96 has excellent characteristics such as high strength and heat resistance comparable to beryllium copper alloy, and electrical conductivity equivalent to phosphor bronze. GMX96 is widely used as contact springs in various applications like connectors, switches, etc.
High Performance Heat resistance Material GMX215
NGK Copper-Nickel-Tin alloy "GMX215" is an age hardening type copper alloy, using spinodal decomposition. GMX215 is a high performance heat resistant spring material with high strength comparable to beryllium copper alloy, and the highest level of superior features such as corrosion resistance and heat resistance among conventional copper alloys. GMX215 is a high-performance spring material suitable for parts used in severe condition such as automobiles and industrial equipment.

Tensile Strength
GMX96 and GMX215 can achieve the strength of 1200 N/mm2 through age hardening (Spinodal decomposition) and can withstand very high bending stress.

Bending Formability
Age hardenable material can be formed into complicated shapes and heat treatment afterwards. Mill-hardened material, which does not require heat-treatment after stamping or forming, has well-balanced performance in strength and formability.

Thermal Stability
Due to less stress relaxation at elevated temperature, GMX96 can be used in a wide range of temperature with little loss of mechanical properties.

Corrosion Resistance
GMX96 and GMX215 has good corrosion resistance and can be used even under severe condition.

Heat Distortion
Due to less deformation (heat distortion) after age hardening treatment, dimensional dispersion after heat treatment is small.

Electrical Conductivity
GMX96 offers conductivity equivalent to that of phosphor bronze. GMX215 offers conductivity about twice that of stainless steel. They are ideal for a wide range of conductive spring applications.
Applications
Recommended Applications | |||||||
---|---|---|---|---|---|---|---|
Connectors | Switches | Motors | Thermostats | Motor brushes | Gears | ||
Market | PC/smartphones | ○ | ○ | - | - | - | - |
Automotive | - | - | ○ | ○ | ○ | ○ | |
Home appliances | - | - | ○ | ○ | - | - | |
Industrial equipment | ○ | - | ○ | ○ | ○ | - | |
Clocks | - | - | - | - | ○ | ○ |
Related Standards
GMX96
- CDA C72700
- JIS C7270
GMX215
- CDA C72950
Copper-Nickel-Tin Properties
Tensile Strength vs. Electrical Conductivity

Chemical Composition
Alloy | Ni | Sn | Mn | Fe | Cu |
---|---|---|---|---|---|
GMX96 | 8.5-9.5 | 5.5-6.5 | max. 0.5 | max. 0.5 | Bal. |
GMX215 | 20.0-22.0 | 4.5-5.7 | max. 0.5 | max. 0.5 | Bal. |
Physical Properties
Alloy | Melting Point (Solidus) (℃) |
Melting Point (Liquidus) (℃) |
Density (g/cm3) |
Specific Heat (J/(kg・K)) |
Electrical Conductivity (%IACS) |
Thermal Conductivity (/℃) |
Modulus of Elasticity (kN/mm2) |
---|---|---|---|---|---|---|---|
GMX96 | 960 | 1090 | 8.93 | 375 | 12 | 17.1×10-6 | 130 |
GMX215 | 1040 | 1160 | 8.93 | 385 | 6 | 16.5×10-6 | 150 |
* Only for reference, not guaranteed values.
Mechanical Properties
Alloy | Temper | Tensile Test1) | Hardness Test1) | Bending Formability, R/t( 90°W) | Heat Treatment (Age hardening) | ||
---|---|---|---|---|---|---|---|
Tensile Strength (N/mm2) |
Elongation (%) |
Vickers Hardness HV |
0° (Good way) |
90° (Bad way) |
|||
GMX96 Age Hardenable |
1/4H | 510 ‒ 620 | Min. 15 | 145 ‒ 220 | 1.0 | 1.0 | (Before H.T.) |
1/4HT | Min. 885 | Min. 5 | Min. 270 | - | - | 375℃×2h | |
1/2H | 590 ‒ 695 | Min. 10 | 180 ‒ 240 | 1.0 | 1.0 | (Before H.T.) | |
1/2HT | Min. 930 | Min. 5 | Min. 285 | - | - | 375℃×2h | |
H | 685 ‒ 835 | Min. 4 | 210 ‒ 270 | 1.0 | 1.5 | (Before H.T.) | |
HT | Min. 980 | Min. 2 | Min. 300 | - | - | 375℃×2h | |
GMX96 Mill Hardened |
HM | 835 ‒ 9802) | Min. 15 | Min. 250 | 1.5 | 1.5 | No need |
EHM | 930 ‒ 10802) | Min. 10 | Min. 280 | 2.5 | 2.5 | No need | |
XHM | Min. 1060 | Min. 3 | Min. 320 | 4.0 | 6.0 | No need | |
GMX215 Age Hardenable |
1/4H | 510 ‒ 620 | Min. 10 | 145 ‒ 220 | 1.0 | 1.0 | (Before H.T.) |
1/4HT | Min. 885 | Min. 2 | Min. 270 | - | - | 450℃×2h | |
1/2H | 590 ‒ 695 | Min. 4 | 180 ‒ 240 | 2.0 | 2.0 | (Before H.T.) | |
1/2HT | Min. 930 | Min. 2 | Min. 285 | - | - | 450℃×2h | |
H | 685 ‒ 835 | Min. 2 | 210 ‒ 270 | 3.0 | 3.0 | (Before H.T.) | |
HT | Min. 980 | - | Min. 300 | - | - | 450℃×2h | |
SH | 825 ‒ 950 | - | 250 ‒ 310 | - | - | (Before H.T.) | |
SHT | Min. 1080 | - | Min. 330 | - | - | 450℃×2h | |
GMX215 Mill Hardened |
HM | 835 ‒ 9802) | Min. 3 | Min. 250 | 3.0 | 5.0 | No need |
EHM | 960 ‒ 11102) | Min. 3 | Min. 280 | - | - | No need | |
XHM | Min. 1060 | Min. 3 | Min. 320 | - | - | No need |
1) Values are applicable to thickness 0.1 mm and over.
2) The upper limits of tensile strength of mill hardened material are for design guidance only.
* Contact us for purchase instructions, if you need a product other than above.
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- Properties (Chemical Composition, Physical Properties, Tensile Strength vs. Electrical Conductivity etc.)
- Technical data (Age Hardening Properties, Bending Formability, Fatigue Strength, Thermal Stability etc.)
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