Properties of 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!
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 | |