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Low Tin Phosphorus Bronze for Terminals and Connectors KLF™-5

CDA No. 50715
Good bend-formability, spring limit and electrical conductivity for Terminals and Connectors.

The KLF™-5 has small amount of iron, phosphorus and tin in chemical compositions, and is low tin Phosphorous Bronze produced with hot rolled process. Hardened by Fe2 precipitates in copper matrix and has good electrical conductivity in comparison to normal Phosphorous Bronze. KLF™-5 is the improvement low tin Phosphorous Bronze of low cost.

Good Points

  1. Has good softening resistance. It is 100 degree higher than phosphorous bronze in stress relaxation.
  2. Has good electrical and thermal conductivity. It is 40 to 50% higher than brass or phosphorous bronze.
  3. Has good strength and equipment of phosphorous bronze.
  4. Has good solderability and platability.
  5. Has good stress corrosion cracking resistance and is better than phosphorous bronze.

Nominal Compositions

Cu-2.0Sn-0.1Fe-0.03P (mass%)


Fig. Stress relaxation resistance of KLF-5.
Fig. Stress Relaxation Resistance of KLF™-5.

1. Physical Properties

Specific Gravity 8.9
Coefficient of Thermal Expansion
17.6 x 10-6/K
Thermal Conductivity (293K) 150 W/m.K
Electrical Resistivity (293K) 49.3 nΩ.m
Electrical Conductivity (293K) 35 %IACS
Modulus Elasticity (293K) 123 GPa

* The above are typical characteristics.

2. Mechanical Properties

Temper Tensile



MHv: 4.9N
1/2H 440~540 450 8 min 140~180
H 530~640 530 5 min 160~200

* Yield strength are nominal values.

* The above tensile strength and hardness are our standard specifications.
We will adjust these specifications by your requests.

3. 90°V-type Bend-formability (MBR)

Temper Good Way Bad Way
1/2H 0 0
H 0 0

* The above are typical characteristics.
The value slightly varies depending on the thickness of specimens.


Terminals and connectors for Automotive, Small terminals and connectors for Consumers etc.


Not used cadmium (Cd), lead (Pb), mercury (Hg), six value chrome (Cr+6), polybrominated biphenyl (PBB) , Polybrominated biphenyl ether (PBDE) restricted with RoHS etc.


Kobe Steel, Ltd. Advanced Materials Business

Copper Rolled Products Unit

Copper Flat Rolled Products Sales Department