Brass Alloys – Cast Alloys

Topics Covered

Introduction
Applications
Composition

Introduction

Brasses or copper zinc alloys have excellent corrosion resistance and strength. Brasses are easily cold worked and contain good ductility and strength. Copper zinc alloys with about 35% of zinc are known as single phase alloys that comprise a solid solution of alpha copper and zinc. Alpha alloys are identified by a change in color based on the increase in the content of zinc up to 35%. This increase in zinc results in the production of a stronger elastic brass alloy along with a decrease in corrosion resistance.

A two phase structure is found in brasses comprising zinc content between 32 and 39%. A beta structure is also available with more than 39% of zinc. The two phase brasses can be easily machined and hot worked. The beta phase is generally harder than the alpha phase.

The primary phase in cast alloys is alpha copper containing about 40% of zinc. The beta phase or the high zinc phase is present in areas between the alpha dendrites. The brasses have a microstructure with almost 40% zinc comprising alpha dendrites along with beta surrounding the dendrites. A Widmanstatten structure is formed when the material is cooled slowly resulting in the alpha precipitating out of the solution at the crystal boundaries.

Lead present in the brasses improves the machinability of brass alloys. Increase in the content of lead results in an increase in size and number of globular lead particles.

Applications

The applications of brasses include:

  • Piercing
  • Coining
  • Blanking
  • Drawing
  • Jewelry
  • Fire extinguishers
  • Springs
  • Lamp fixtures
  • Radiator cores
  • Flexible hose
  • Gold plate bases
  • Ammunition

The cast brasses are used in applications that include:

  • Fittings
  • Low pressure valves
  • Architectural trim
  • Decorative hardware
  • Plumbing fixtures
  • Bearings and gears

Composition

The composition of brass alloys is outlined in the following table.

Copper Alloy No. Cu Sn Pb Zn Fe Sb Ni Mn As S P Al Si Other Named Elements Status Inactive Date
C852001 70.0-74.02 .7-2.0 1.5-3.8 20.0-27.0 .6 .20 1.0 - - .05 .02 .005 .05 - Active
C85210 70.0-75.0 1.0-3.0 2.0-5.0 Rem. .8 - 1.0 - .02-.06 - - .005 .005 - Inactive
C853001 68.0-72.0 .50 .50 Rem. - - - - - - .50 - - - Inactive 08/09/1977
C85310 68.0-73.0 1.5 2.0-5.0 Rem. .8 - 1.0 - .02-.06 - - .01 - - Inactive 03/09/1992
C854004 65.0-70.0 .50-1.5 1.5-3.8 24.0-32.0 .7 - 1.03 - - - - .35 .05 - Active
C854505 60.0-64.0 .50-1.5 .09 Rem. .30-1.0 - 1.03 .6 - - - 1.0 - - Active
C855001 59.0-63.0 .20 .20 Rem. .20 - .203 .20 - - - - - - Active
*C855505 59.0-64.0 .30 .09 Rem. .15 - .206 - - - - .30 .30-1.0 - Active
C85600 59.0-63.0 .20 .20 Rem. - - .20 .20 - - - - - - Inactive 02/18/1982
C85610 63.0-66.0 1.2-2.0 1.0-2.0 Rem. .10-1.0 - 2.0 - - - - - - 1.0Be Inactive 05/19/1982
C857007 58.0-64.0 .50-1.5 .8-1.5 32.0-40.0 .7 - 1.03 - - - - .8 .05 - Active
C85710 58.0-63.0 1.0 1.0-2.5 Rem. .8 - 1.0 .50 - - - .20-.8 .05 - Inactive 03/09/1992
C858007 57.0min 1.5 1.5 31.0-41.0 .50 .05 .50 .25 .05 .05 .01 .55 .25 - Active
C859008 58.0-62.0 1.5 .09 31.0-41.0 .50 .20 1.53 .01 - .10-.65 .01 .10-.6 .25 .20B .20Zr Active
C859108 58.0-62.0 1.5 .09 31.0-41.0 .50 .20 1.53 .01-.20 - .10-.65 .01 .10-.6 .25 .20B .20Zr Active
C859208 58.0-62.0 1.5 .09 31.0-41.0 .50 .20 1.53 .20 - .1 .01 .10-.6 .25 .20B .10C .30Ti .20Zr Active
C859308 58.0-62.0 1.5 .09 31.0-41.0 .50 .10-1.5 1.53 .20 - .10-.65 .01 .10-.6 .25 .20B .10C .30Ti .20Zr Active

1Cu + Sum of named elements, 99.1% min.
2In determining Cu min., Cu may be calculated as Cu + Ni.
3Ni value includes Co.
4Cu + Sum of named elements, 98.9% min.
5Cu + Sum of named elements, 99.5% min.
6Includes Co.
7Cu + Sum of named elements, 98.7% min.
8Cu + Sum of named elements, 99.3% min.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit