Metal alloys are mixtures of metals, or a metal and another element blended together. Distinct from an impure metal, alloys are unique because the added impurities of another metal or element are usually desirable and typically beneficial.
It’s not always easy to decide which alloys represent the best materials for a fabrication project. Weighing out the pros and cons of an alloy may find that a more expensive alloy is the best choice because of its strength, weight, or workability versus a cheaper alloy that requires more man-hours to adapt to the particular application.
As raw metals, most elemental metallic forms are usually quite soft or brittle, making them incapable of withstanding the requirements of fabrication. The easiest and most practical solution is to mix them, creating an alloy that harnesses the desirable properties of multiple materials in one metal alloy.
For example, steel is one of the most commonly used alloys on earth. It’s made from adding non-metallic carbon to iron. Adding chromium to iron makes stainless steel that withstands the effects of corrosion.
Pros and Cons of 4 Different Fabrication Alloys
Carbon Steel
Iron alloyed with an interstitial, or impure, carbon usually in the range of 0.12-2%. When the amount of added carbon is increased the steel becomes harder and stronger through heat treatments. It also becomes less ductile, or malleable. Higher carbon content also will reduce the weldability of steel, and lower the melting point of the alloy. Mid-to high level carbon steel has applications in forging and automotive parts, high strength wire, springs, knives and swords. Carbon steel is typically a poor conductor of electricity.
Stainless Steel
Iron alloyed with a minimum of 10.5% chromium by mass. Stainless steel does not easily corrode, rust or stain with water as ordinary carbon steel does. When chromium at a level of 26% is added, the alloy is able to withstand corrosion in extreme environments. Like carbon steel, stainless is a poor conductor of electricity. Its familiar luster, and low maintenance make stainless steel an ideal material for a vast array of applications from kitchen/housewares, hardware, surgical instruments, auto and aerospace structural alloy and construction materials in large buildings like bridges, passenger railcars, airport roofing, and storage tanks.
Aluminum alloy
Aluminum in its elemental form is a fairly soft and lightweight metal and is commonly alloyed with copper, magnesium, tin or zinc to increase its strength, durability, mass and workability. About 85% of aluminum alloys are used for wrought products. Aluminum alloys are easily workable. Cast aluminum products are relatively low-cost due to its low melting point, however they do have lower tensile strength. Aluminum alloys are widely used in engineering applications and components where lightweight and resistance to corrosion is required. Aluminum alloys are used in aerospace projects, automotive engine components, shipbuilding and other saltwater sensitive applications. Aluminum alloys will warp at high temperatures and unlike steel, do not glow red before melting. Aluminum alloys also feature a lower fatigue limit than steel and will continually weaken with repeated stress. They are rarely used in fabrication applications that require high fatigue rates.
Titanium alloy
Features very high tensile strength and toughness. Titanium alloys are light in weight, have superior corrosion resistance properties and can withstand extreme temperatures. Most titanium alloys are alloyed with aluminum (6%) and vanadium (4%) by weight. Titanium alloys are heat-treated to increase their strength in terms of fracture toughness, fatigue strength and high temperature strength. It’s extremely high cost, both in raw materials and processing, have limited its common use to that of military, aerospace, medical devices, high stress components like connecting rods in engines and railway applications, as well as expensive sports cars.
Selecting the right alloy for your fabrication project is a critically important aspect of its construction. At Saskarc Fabrication, we know our materials inside and out, and can help your firm or company to select the correct material for the job.
