Silicon bronze are an alloy that contains copper as a primary metal, and also contains small amount of manganese and tin. Silicon bronze is used in marine environments because silicon bronze resist saltwater corrosion. Because silicon bronze does not create black stains in wooden structures like steel do, boatbuilders use silicon bronze to plank sailboats and dories.
Additionally, silicon bronze form a patina over time, which makes it suitable for architect who use it for decorative doors and building facades. Because silicon bronze is both ductile and weldable, it is often used for building docks and pier, or for restoration projects. Silicon bronze metal contain different strength levels depending upon the processing of the metal.
Silicon Bronze: Uses and Care
Annealed silicon bronze contain a tensile strength of 70,000 PSI, while cold-worked silicon bronze contain a tensile strength of 100,000 PSI. Silicon bronze is a non-magnetic and non-sparking material. Because silicon bronze is a non-sparking material, it is safe to utilize in fuel bays.
However, silicon bronze is a soft metal than steel. If a worker applies too much torque to a silicon bronze bolt, the head of the bolt will round off. To avoid rounding the head of a silicon bronze bolt, one must utilize a torque chart with the bolt to ensure the correct torque values for the silicon bronze material; utilizing the correct torque values will prevent twisting the silicon bronze into scrap metal.
The torque that must be utilized for silicon bronze metals change depending upon whether the silicon bronze bolts and threads are dry or lubricated. For a 3/8-inch UNC silicon bronze bolt, the dry torque for annealed silicon bronze is 17 foot-pound, while cold-worked silicon bronze bolts have a dry torque of 25 foot-pounds. For a 3/8-inch UNC silicon bronze bolt that is lubricated with a bronze-safe lubricant, the torque is 19 foot-pounds.
Using lubricant reduce the amount of torque that is required to achieve the desired torque for the silicon bronze metal by 20%. Graphite-based anti-seize lubricants should not be used for silicon bronze metals because they can cause galvanic corrosion between the silicon bronze and other metal in contact with the silicon bronze. Instead, one should use beeswax or paraffin.
Additionally, hand tools should be used to apply the necessary torque to silicon bronze bolts and screws because impact drivers can shear the heads of the silicon bronze bolts or screws. When using silicon bronze along with other metal, it is necessary to consider the galvanic series to ensure that there is no galvanic corrosion of the silicon bronze. Silicon bronze is compatible with metals like brass and copper due to there relation to the composition of silicon bronze.
Additionally, silicon bronze is compatible with 316 stainless steel, but only if the 316 stainless steel remains dry as it can suffer from crevice corrosion when expose to brine. Furthermore, silicon bronze should not be used in direct contact with aluminum as this will lead to the rapid corrosion of the aluminum. If the use of silicon bronze in contact with aluminum is necessary, then the metals should be isolated from one another using plastic washers.
Silicon bronze metal is different from metals like carbon steel and stainless steel. Carbon steel metal is stronger than silicon bronze and is less expensive to purchase, however, it will rust quick and can stain wood. Stainless steel metal is more resistant to salt than carbon steel, however it is prone to pitting as it trap moisture within the crevices of the metal.
Silicon bronze metal has a torque level of 60 to 70 percent of the torque level of Grade 5 steel, which is provided to the yield point of the silicon bronze metal. There are various type of silicon bronze metal fasteners available for different types of task. Hex bolts are used for machinery, carriage bolts are used for boat timbers, wood screws are used for hardwoods, and lag bolts are used for heavy metal frame.
Additionally, silicon bronze metal is available in various size. The larger the size of the silicon bronze metal fastener, the more higher the tensile strength of that fastener. Silicon bronze metal will change its appearance over time due to reaction with the environment.
New silicon bronze metal have a rose-gold color to it. After one month of exposure to the environment, the metal will turn to an amber color. After one year the metal will turn to a chocolate brown color.
After many decades of exposure to the environment the metal will turn to a verdigris green color, which act as a protective layer for the remaining silicon bronze metal. Additionally, there is no need to polish silicon bronze metal to maintain it, as it naturaly develops to these various color. To ensure that silicon bronze metal remains secure in the materials that it fastens, the holes must be prepared by drilling pilot holes to approximately 98 percent of the diameter of the shank of the silicon bronze metal fastener.
