Metallurgical specifications of all configurations of Bronze C90700

General Characteristics
C90700 Gear Bronze is a hard, strong alloy with good corrosion resistance, especially in seawater. As a bearing material it resists both wear and fatigue applications. It is moderately machinable. C 907 is widely used for gears and worm wheels, bearings, marine fittings, piston rings and pump components.
Typical Chemical Composition

Weight % Cu⁽¹⁾⁽²⁾ Sn Pb Zn Fe Sb Ni+Co S P⁽³⁾ Al Si Mn

minimum 88.0 10.0 — — — — — — — — — —

maximum 90.0 12.0 .50 .50 .15 .20 .50 .05 .30 .005 .005 —

(1)     Cu + sum of named elements, 99.4% min.

(2)     In determining Cu-min., Cu may be calculated as Cu + Ni.

(3)     For continuous castings, P shall be 1.5% max.

Weight %	Cu⁽¹⁾⁽²⁾	Sn	Pb	Zn	Fe	Sb	Ni+Co	S	P⁽³⁾	Al	Si	Mn
minimum	88.0	10.0	—	—	—	—	—	—	—	—	—	—
maximum	90.0	12.0	.50	.50	.15	.20	.50	.05	.30	.005	.005	—

Characteristics		English	Metric
Nominal density	20°C / 68°F	0.317 lbs/in³	8.77 g/cm³
Melting range	Liquidus	1830 °F	999 °C
Melting range	Solidus	1528 °F	831 °C
Specific heat	20°C / 68°F	0.09 BTU/lb – °F	377 J/KG- °K
Coefficient of thermal expansion	68°F – 392°F 20°C – 200°C	10.2 micro in/in- °F	18.4 micro m/m- °K
Thermal conductivity	20°C / 68°F	40.8 BTU/ft- hr – °F	70.6 W/m – °K
Electrical resistivity	20°C / 68°F	15 nΩ ∙ m
Electrical conductivity	Volumetric: 20°C / 68°F	10% IACS

Mechanical Properties

Temper Tensile Hardness

Ultimate Yield Elongation in 50 mm

(2 in.)
Rockwell B

KSI MPa KSI MPa %

As cast 303 44 152 22 20 47

Heat treated 379 55 207 30 16 65
Specifications

Centrifugal / Sand Castings Continuous Castings Ingot

ASTM – B427 ASTM – B504 ASTM – B30
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Bronze Alloy C90700