Properties of 651 Silicon Bronze

Fair Wind Fasteners - 651 Silicon Bronze

Silicon bronze is popular in boatbuilding and for the marine environment because it's so well suited to the task. But be careful when purchasing silicon bronze fasteners and other hardware for your boat building project. Many online retailers and suppliers will sell you what they call "Silicon Bronze" for a cheap price, but after multiple stripped heads and twisted shanks you'll soon find out why they were so cheap!

poor quality marine fasteners, 651 bronze, silicon bronze

The problem is rampant! Manufacturers will attempt to cut costs by using inferior alloys and inferior manufacturing techniques, then sell you their "Silicon Bronze" at what seems to be a discount price. The "discount" is quickly negated after 20% of the fasteners strip out, and even more negated if the alloy is so poor that the build you've put all that work in to starts popping off planks just a few years down the road. Benjamin Franklin's words couldn't be more apt.

At Fair Wind Fasteners, we NAME the alloy. When you order from us we guarantee the alloy that is used in our fasteners. Our wood screws, for example, are true 651 Silicon Bronze (also known as C65100 low-silicon bronze B) which is the tried and true absolute best for boat building, the marine environment, and a variety of other uses.

Our true, guaranteed 651 Silicon Bronze fasteners are made out of a superior alloy with the following properties:

Physical Properties Metric Imperial Notes
Density 8.75 g/cc 0.316 lb/in³ at 20°C (68°F)
Mechanical Properties
Hardness, Rockwell F 55 55
Tensile Strength, Ultimate 275 MPa 39900 psi
Tensile Strength, Yield 105 MPa 15200 psi 0.5% extension under load
Elongation at Break 50 % 50 % In 50 mm
Modulus of Elasticity 115 GPa 16700 ksi
Machinability 30 % 30 % UNS C36000 (free-cutting brass) = 100%
Shear Modulus 44 GPa 6380 ksi
Electrical Properties
Electrical Resistivity 1.44e-005 ohm-cm 1.44e-005 ohm-cm
Thermal Properties
CTE, linear 250°C 18 µm/m-°C 10 µin/in-°F from 20-300°C (68-570°F)
Heat Capacity 0.38 J/g-°C 0.0908 BTU/lb-°F
Thermal Conductivity 57 W/m-K 396 BTU-in/hr-ft²-°F at 20°C (68°F)
Melting Point 1030 – 1060 °C 1890 – 1940 °F
Solidus 1030 °C 1890 °F
Liquidus 1060 °C 1940 °F
Processing Properties
Annealing Temperature 475 – 675 °C 887 – 1250 °F
Hot-Working Temperature 700 – 875 °C 1290 – 1610 °F