Copper Alloy (UNS C94700)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Welding
     Heat Treatment
Applications

Introduction

The copper family has around 400 different alloys. Copper is known to possess high thermal and electrical conductivity. Compared to most metals, copper can freely form alloys with several other elements.

The following datasheet gives an overview of UNS C94700 copper casting alloy.

Chemical Composition

The following table shows the chemical composition of UNS C94700 copper alloy.

Element Content (%)
Copper, Cu 88
Tin, Sn 5
Nickel, Ni 5
Zinc, Zn 2

Physical Properties

The physical properties of UNS C94700 copper alloy are tabulated below.

Properties Metric Imperial
Density 8.84 g/cm3 0.319 lb/in3

Mechanical Properties

The mechanical properties of UNS C94700 copper alloy are outlined in the following table.

Properties Metric Imperial
Tensile strength (as cast) 345 MPa 50000 psi
Yield strength (as cast) 159 MPa 23100 psi
Elongation at break (as cast) 35% 35%
Poisson's ratio 0.34 0.34
Elastic modulus 117 GPa 17000 ksi
Hardness, Brinell (500 kg) 85 85
Machinability (as cast; UNS C36000 (free-cutting brass) = 100) 30 30

Other Designations

Other designations that are equivalent to UNS C94700 copper alloy include:

  • ASTM B30
  • ASTM B505
  • ASTM B584
  • ASTM B763
  • QQ C390
  • SAE J461
  • SAE J462

Fabrication and Heat Treatment

Machinability

The machinability rate of UNS C94700 copper alloy is 20 at heat treated, and 30 as cast.

Welding

UNS C94700 copper alloy can be welded using brazing, soldering, gas shielded arc welding, oxyacetylene welding, and coated metal arc welding methods. Carbon arc welding method is not used for welding this alloy.

Heat Treatment

UNS C94700 copper alloy can be stress relieved at 260°C (500°F). The time taken for stress relieving is about 1 hr/in. of section thickness. It does not respond to heat treatment. Heat treating process can be performed at temperatures between 775 and 800°C (1425 and 1475°F). Time taken for heat treating is about 2 h/in. of section thickness. Water is used as a quenching medium. Air is used as a quenching medium for performing precipitation hardening process at temperatures ranging between 305 and 325°C (580 and 620°F). Time taken for performing this process is 5 h.

Applications

UNS C94700 copper alloy is mainly used in the following applications:

  • Wear guides
  • Feeding mechanisms
  • Nozzles
  • Valve stems and bodies
  • Shift forks
  • Circuit breaker parts
  • Piston cylinders
  • Gears

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