Material
The substance from which the screw is made.
Brass
This material has a general composition of 2/3 copper and 1/3 zinc. This material has a distinctive bright golden coloring and is primarily used in aesthetic settings or in applications where low friction is necessary. As an electroplated finish it is nonmagnetic and resists corrosion well. Often used when sparking is an issue. It has excellent cold working (forming at room temperature) properties. Used in locks, gears, doorknobs, plumbing, electrical applications and musical instruments.
Silicon Bronze
This alloy is 96% copper and around 2 - 3% silicon. With very high corrosion resistance, it is commonly used in salt-water, fresh water, sewage, and atmospheric applications. It is quite durable and similar to low carbon steel in hardness. It is a popular alloy because of its combination of strength, ductility, corrosion resistance and weldability. It is commonly seen in architecture, marine applications, pumps and boilers.
Stainless Steel
An iron based material with a minimum of 10.5% chromium. This material is known for its corrosion resistance and has varying strengths depending on the amount of chromium and nickel alloy. The chromium forms a protective layer when exposed to oxygen, keeping the steel underneath from corroding. There are over 150 grades of this material with the 304 and 316 series being the most common.
Steel
The most common material used in fasteners, this material is predominantly iron mixed with carbon. It offers the highest strength compared to other metals and elements, but is the least corrosion resistant. Also known as Carbon Steel.
