Copper Alloy No. C91700

Nickel Gear Bronze

Chemical Composition % by weight

Element	Nominal	Minimum	Maximum
Aluminum	-	-	.005
Antimony	-	-	.20
Copper	86.5	84	87
Iron	-	-	.15
Lead	-	-	.25
Nickel	1.5	1.2	2
Phosphorus	-	-	.30
Silicon	-	-	.005
Sulfur	-	-	.05
Tin	12	11.3	12.5
Zinc	-	-	.25

Applications

Gears

Hardness*	Brinell Hardness (500 kg load)	106
Tensile Strength**	KSI	60
Yield Strength **	KSI (0.5% Ext. under load)	32
Elongation**	% in 2 inch	16

**Test values are nominal approximations and depend on specimen size and orientation.

Physical Properties

Thermal Conductivity	BTU/ (sq ft-ft-hr-F)	40.8
Specific Heat	BTU/lb/ºF @ 68F	.09
Thermal Expansion	Per °F from 68 F to 392 F	.0000100
Density	lb/cu in @ 68 F	.316
Electrical Conductivity	% IACS @ 68 F	10
Modulus of Elasticity	KSI	15,000

*Volume basis

Stress relieving temperature	500 F or 260 C
Time at temperature	1 hour per inch of section thickness
Responds to heat treatment	No
Machinability rating (Free Cutting Brass=100)	20
Suitability for being joined by:	Soldering/Excellent
	Brazing/Good*
	Oxyacetylene Welding/Fair
	Gas Shielded Arc Welding/Fair
	Coated Metal Arc Welding/Fair

*Since brazing is performed at temperatures within the hot-short range, strain must be avoided during the brazing and cooling of this alloy.

The values listed above represent reasonable approximations suitable for general engineering use. Due to commercial variations in composition and to manufacturing limitations, they should not be used for specification purposes. See applicable A.S.T.M. specification references.