Leaded Brasses - Wrought Alloys

Topics Covered

Introduction
Overview
Composition

Introduction

Brass is a copper-zinc alloy, which is ductile and easy to shape. The amount of zinc in the brass alloy can be varied from 5 to 45% to form different alloys with unique properties.

Two major types of brasses include alpha brasses and alpha-beta/duplex alloys. Brasses containing less than 35% of zinc and one solid solution termed alpha brasses, which are suitable for cold working.

Brasses containing zinc of more than 35% are known as alpha-beta/duplex alloys, which can be hot worked. Brass alloys are available in various colors and thus they are preferred for applications which require aesthetic appeal.

Nearly 3% of lead is added to alpha-beta brasses to ensure free-machining properties of brasses. Wrought alpha brasses do not contain lead as the addition of lead results in damage in the absence of adequate beta phase during hot working. Lead can provide pressure tightness and improve machinability of brasses by covering the shrinkage pores.

Overview

Lead brasses offer high corrosion resistance, good strength and excellent machinability. Low, medium and high-leaded brasses are three major types of lead brasses with maximum of 3.5% lead content.

Lead brasses have similar microstructure as that of the unleaded brasses. This microstructure has discrete lead particles present in the inter-dendritic regions or grain boundaries, and is formed as a result of zinc content.

The wrought lead brasses are named as UNS C31200 to C38500, and the cast lead brasses are designated as C83600 to C97300.

The alloys containing less zinc content have single-phase solid solution alpha dendrites with lead particles scattered all through the inter-dendritic regions. The alloys containing higher zinc content have a beta microstructure and alpha and beta structures. These higher zinc content alloys have alpha and beta phase mixture and lead particles that are present as discrete particles in the microstructure.

Composition

The composition of leaded brasses is outlined in the following table.

Copper Alloy No. Previous Trade Name Cu Pb Fe Zn Other Named Elements Status Inactive Date
C31000 Copper Zinc Lead Alloy 89.0-91.0 .30-.7 .10 Rem. - Inactive 07/01/1974
C312001 - 87.5-90.5 .7-1.2 .10 Rem. .25Ni Active  
C314001 Leaded Commercial Bronze 87.5-90.5 1.3-2.5 .10 Rem. .7Ni Active  
C316001 Leaded Commercial Bronze (Nickel-Bearing) 87.5-90.5 1.3-2.5 .10 Rem. .7-1.2Ni .04-.10P Active  
C320001 Leaded Red Brass 83.5-86.5 1.5-2.2 .10 Rem. .25Ni Active  
C32500 Copper Zinc Lead Alloy 72.0-74.5 2.5-3.0 .10 Rem. - Inactive 07/01/1974
C32510 Leaded Brass 69.0-72.0 .30-.7 - Rem. .02-.06As Inactive 03/09/1992
C330001 Low Leaded Brass (Tube) 65.0-68.0 .25-.7 .07 Rem. - Active  
C33100 Leaded Brass 65.0-68.0 .8-1.5 .06 Rem. - Inactive 03/09/1992
C332001 High Leaded Brass (Tube) 65.0-68.0 1.5-2.5 .07 Rem. - Active  
C335001 Low-Leaded Brass 62.0-65.0 .25-.7 .15 Rem. - Active  
C33530 Leaded Brass 62.5-66.5 .30-.8 .10 Rem. .02-.06As Inactive 03/09/1992
C340001 Medium Leaded Brass, 64-1/2% 62.0-65.0 .8-1.5 .152 Rem. - Active  
C342001 High Leaded Brass, 64-1/2% 62.0-65.0 1.5-2.5 .152 Rem. - Active  
C34400 Leaded Brass 62.0-66.0 .50-1.0 .10 Rem. - Inactive 02/24/1981
C345001 - 62.0-65.0 1.5-2.5 .15 Rem. - Active  
C34700 Leaded Brass 62.5-64.5 1.0-1.8 .10 Rem. - Inactive 02/24/1981
C34800 Leaded Brass 61.5-63.5 .40-.8 .10 Rem. - Inactive 02/24/1981
C34900 Leaded Brass 61.0-64.0 .10-.50 .10 Rem. - Inactive 02/24/1982
C350001 Medium Leaded Brass, 62% 60.0-63.03 .8-2.0 .152 Rem. - Active  
C353004 High Leaded Brass, 62% 60.0-63.03 1.5-2.5 .152 Rem. - Active  
C353304 DZR Brass 59.5-64.0 1.5-3.55 - Rem. .02-.25As Active  
C35340 Leaded Brass 60.0-63.0 1.5-2.5 .10-.30 Rem. - Inactive 03/09/1992
C353504 Leaded Brass 61.0-63.0 2.0-4.5 .40 Rem. .05-.30Ni .05-.20P .30Sn Active  
C356004 Extra High Leaded Brass 60.0-63.0 2.0-3.0 .152 Rem. - Active  
C360004 Free-Cutting Brass 60.0-63.0 2.5-3.0 .35 Rem. - Active  
C360104 Leaded Brass 60.0-63.0 3.1-3.7 .35 Rem. - Active  
C36200 Leaded Brass 60.0-63.0 3.5-4.5 .15 Rem. - Inactive 03/09/1992
C36300 Copper-Zinc-Lead Alloy 61.0-63.04 .25-.7 .15 Rem. .04-.15P Active  
C365001 Leaded Muntz Metal, Uninhibited 58.0-61.0 .25-.7 .15 Rem. .25Sn Active  
C36600 Leaded Muntz Metal, Arsinical 58.0-61.0 .25-.7 .15 Rem. .02-.06As .25Sn Inactive 03/09/1992
C36700 Leaded Muntz Metal, Antimonial 58.0-61.0 .25-.7 .15 Rem. .02-.10Sb .25Sn Inactive 03/09/1992
C36800 Leaded Brass 58.0-61.0 .25-.7 .15 Rem. .02-.10P .25Sn Inactive 03/09/1992
C370001 Free-Cutting Muntz Metal 59.0-62.0 .8-1.5 .15 Rem. - Active  
C371001 - 58.0-62.0 .6-1.2 .15 Rem. - Active  
C377004 Forging Brass 58.0-61.0 1.5-2.5 .30 Rem. - Active  
C377104 - 56.5-60.0 1.0-3.0 .30 Rem. - Active  
C37800 Leaded Brass 56.0-59.0 1.5-2.5 .30 Rem. - Inactive 03/09/1992
C380004 Architectural Bronze, Low Leaded 55.0-60.0 1.5-2.5 .35 Rem. .50Al .30Sn Active  
C38010 Leaded Brass 55.0-60.0 1.5-3.0 .30 Rem. .10-.6Al Inactive 03/09/1992
C385004 Architectural Bronze 55.0-59.0 2.5-3.5 .35 Rem. - Active  
C38510 Leaded Brass 56.0-60.0 2.5-4.5 - Rem. - Inactive 03/09/1992
C38590 Leaded Brass 56.5-60.0 2.0-3.5 .35 Rem. - Inactive 03/09/1992
C38600 Leaded Brass 56.0-59.0 2.5-3.5 .35 Rem. .02Sb Inactive 02/16/1982

1Cu + sum of named elements, 99.6% min.
2For flat products, the iron shall be .10% max.
3Cu, 61.0% min. for rod.
4Cu + sum of named elements, 99.5% min.
5Pb may be reduced to 1.0% by agreement.

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