Chromium Copper Alloy UNS C18400

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
     Cold Working
     Welding
     Forging
     Machinability
     Hot Working
Applications

Introduction

Copper alloys are available in more than 400 varieties. Each copper alloy variety has specific properties that suit a number of manufacturing processes, environments and applications. Some of the copper alloy forms include:

  • Beryllium copper
  • Nickel silver
  • Tin bronze
  • Brass
  • Phosphor bronze
  • Gunmetal
  • Aluminum bronze
  • Copper-nickel

UNS C18400 chromium copper alloys features moderately high elevated strength and conductivity 80% IACS. The datasheet below provides an overview of UNS C18400 chromium copper alloys.

Chemical Composition

The chemical composition of UNS C18400 chromium copper alloys is outlined in the following table.

Element Content (%)
Cu 99.2
Cr 0.8

Physical Properties

The following table shows the physical properties of UNS C18400 chromium copper alloys.

Properties Metric Imperial
Density 8.89 g/cc 0.321 lb/in³
Melting point 1070.0°C 1958°F

Mechanical Properties

The mechanical properties of UNS C18400 chromium copper alloys are displayed in the following table.

Properties Metric Imperial
Tensile strength 234-593 MPa 33900-86000 psi
Yield strength (depending on temper) 97.0-531 MPa 14100-77000 psi
Elongation at break (in 127 mm (2in.)) 40.00% 40.00%
Machinability (UNS C36000 (free-cutting brass) = 100) 20 20
Shear modulus 50.0 GPa 7250 ksi
Poisson's ratio 0.34 0.34
Elastic modulus 117 GPa 16969 ksi

Thermal Properties

The thermal properties of UNS C18400 chromium copper alloys are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@20-100°C/68-212°F) 17.6 µm/m°C 9.78 µin/in°F
Thermal conductivity (@20°C/68°F) 171 W/mK 1190 BTU in/hr.ft².°F

Other Designations

Equivalent materials to UNS C18400 chromium copper alloys are:

  • MIL C-19311
  • SAE J461
  • SAE J463

Fabrication and Heat Treatment

Cold Working

UNS C18400 alloys can be cold worked in an excellent manner.

Welding

UNS C18400 alloys can be welded using brazing, gas shielded arc welding, butt welding and soldering processes. Welding processes not recommended for these alloys include seam welding, oxyacetylene welding, spot welding and coated metal arc welding.

Forging

UNS C18400 alloys can be hot worked between 760 and 871°C (1400 and 1600°F). The hot forgeability rating of these alloys is 80.

Machinability

The machinability rating of UNS C18400 alloys is 20.

Hot Working

UNS C18400 alloys have good hot forming capacity.

Applications

UNS C18400 alloys are also used in mechanical and electrical power transmission devices, high-strength fasteners for elevated-temperature service and circuit breaker parts. They are also used in welding equipment components that include wheels, tips and clamps.

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