1.1 This specification establishes copper-tin alloy (phosphor bronze), copper-tin-lead alloy (leaded phosphor bronze), and copper-tin-lead-zinc alloy (bearing bronze), plate, sheet, strip, and rolled bar. The phosphor bronzes commonly are used for deep drawing into bellows and stamping and forming into spring devices and into terminals and connectors for electrical apparatus because they combine high strength with high elongation. The leaded phosphor bronzes are used where strength, corrosion resistance, and machinability are required. The bearing bronze is used in bushings, bearings, and load-bearing thrust washers. The following alloys are covered:

Copper Alloy UNS No.	Nominal Composition, %				Previously Used Designation
Copper Alloy UNS No.	Copper	Tin	Zinc	Lead	Previously Used Designation

C51000	95	5	. . .	. . .	A1
C51100	96	4	. . .	. . .	A
C51180	96	4	. . .	. . .	. . .
C51900	94	6	. . .	. . .
C52100^A	92	8	. . .	. . .	C
C52180	92	8	. . .	. . .	. . .
C52400	90	10	. . .	. . .	D
C53400	94	5	. . .	1	B1
C54400	88	4	4	4	B2
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^A SAE Specification CA 521 conforms to the requirements of UNS No. C52100.

Note 1 - All of the above alloys contain small amounts of phosphorus, used as a deoxidant in melting, and to enhance the mechanical properties.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.