Leaded Brasses - Wrought Alloys

Aug 6 2013

Topics Covered

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.