Metals Codes - 7: Copper Alloy Codes
VMS Forum | Library | Start Page | Previous Page| Next Page
WARNING: Machine tools present a safety hazard. Improper operation can result in severe injury. These topics are for non-laboratory study only and are not to be used in conjunction with the operation of any tool or machine described herein. Never use a machine tool without the supervision of a qualified instructor.

Copper alloys are designated by UNS as CXXXXX as shown

Brass (left) is an alloy of Copper and Zinc (5 to 45%), it increases strength and hardness but is less resistant to stress corrosion cracking.

Bronze is an alloy of copper and tin . It is more expensive than brass but its corrosion resistance, strength, and fatigue resistance is better.

The UNS designation system is straightforward  The copper designator is the letter C followed by five digits.

The Key to the UNS Copper Numbering System

    • If the first digit is "1" as in C1xxxx then this designates pure wrought copper
      • If the second digit is "0" through "5" as in C10xxx through C15xxx then this designates pure wrought copper with no alloys
      • If the second digit is "6" through "9" as in C16xxx through C19xxx then this designates wrought copper with alloys in very small amounts
    • If the first digit is "2" as in C2xxxx then this designates yellow brass (heavy in zinc)
    • If the first digit is "3" as in C3xxxx then this designates leaded brass (zinc with lead)
    • If the first digit is "4" as in C4xxxx then this designates tin brass (mostly zinc with some tin)
    • If the first digit is "5" as in C5xxxx then
      • If the second digit is "0" through "2" as in C50xxx through C52xxx then this designates phosphor bronze (phosphor with tin)
      • If the second digit is "3" or "4" as in C53xxx or C54xxx then this designates leaded phosphor bronze (tin, lead, and phosphor)
    • If the first digit is "6" as in C6xxx then this designates aluminum bronze (aluminum and tin)
    There are many more brasses and bronzes but the above listed should serve the machinist's needs well enough. One important thing to remember is C2, C3, and C4 is brass. C5 and C6 is bronze.
    VMS Forum | Library | Start Page | Previous Page| Next Page

    label: standards, UNS, AISI,ASTM, ASE, coding, steel, stainless steel, tool steel, aluminum, copper, austenetic, martensitic, ferritic, precipitatin hardening