Alloys 101

An alloy is a combination of a base metal with additional materials, either metal or nonmetal. Alloys are typically created by melting the materials, mixing them together, and allowing them to cool and solidify. Metal alloys are a popular choice due to their enhanced chemical and mechanical properties. Depending on the intended application, different alloying materials can be added to improve strength, machinability, hardness, corrosion resistance, and more.

There are a wide array of metal alloys available, each with its own unique properties and ideal applications.

Titanium Alloy
Titanium alloys offer an immense amount of strength and corrosion resistance while maintaining malleability. Their versatility and excellent strength-to-weight ratio make titanium alloys a popular option for military and aerospace applications such as missiles and engines. Other industries utilizing this alloy include automotive, medical, telecommunications, and more.

Common grades of titanium alloys include:

• Ti 6Al-4V (Grade 5). This is the most popular titanium alloy, often found in marine, medical, and chemical processing applications.
• Ti 6AL-4V ELI (Grade 23). Its biocompatibility makes Grade 23 an ideal option for medical applications, particularly surgical. Grade 23 titanium alloy is also highly malleable.
• Ti 3Al 2.5 (Grade 12). This alloy is an excellent choice for manufacturing applications thanks to its weldability, corrosion resistance, and similarity to stainless steel.
• Ti 5Al-2.5Sn (Grade 6). This option is often found in aircraft due to its strength and high-temperature stability.
• Ti 3Al-2.5V (Grade 9). Grade 9 titanium offers medium strength, great corrosion resistance, and the ability to withstand higher temperatures. These properties make it a popular choice in various industrial and aerospace applications.

Nickel Alloy

Nickel alloys feature high resistance to pressure and extreme temperatures, making them an ideal option for applications in harsh environments, such as deep sea mining, steam turbines, and jet engine blades. Nickel alloys are non-ferrous and are highly resistant to corrosion. They also provide high levels of strength and toughness.

Common nickel alloys include:

• Nickel Alloy 20. This alloy includes copper and molybdenum, and it offers great resistance to pitting, corrosion, and crevice corrosion. Its ability to withstand harsh chemicals makes it a popular choice for the production of pharmaceuticals, explosives, solvents, gasoline, and food.
• Nickel Alloy 155. Combining nickel with chromium and cobalt, this alloy is often utilized in applications requiring oxidation resistance, the ability to withstand high temperatures and strength.
• Nickel Alloy 200. This 99.6% pure alloy offers resistance to corrosive and caustic environments, high thermal and electrical conductivity, and unique magnetic properties. It is ideal for industries that need to maintain the purity of their products such as food handling, synthetic fiber manufacturing, and more.
• Nickel Alloy 201. This grade is similar to grade 200 but with a higher carbon content. This means it can be utilized in higher-temperature applications. This alloy offers various benefits including resistance to various reducing chemicals, high electrical and thermal conductivity, and more.
• Nickel Alloy 255. This alloy combines nickel, chromium, and iron to create a material with great corrosion and erosion resistance. Its excellent corrosion resistance makes grade 255 ideal for chemical processing applications.
• Nickel Alloy 400. Grade 400 offers high strength, corrosion resistance, and the ability to work in a range of temperatures. Its anti-corrosive properties and toughness make it suitable for heavy-duty applications like transfer piping used in oil refineries.
• Nickel Alloy 600. This nickel-chromium alloy is well-known for its oxidation resistance at higher temperatures. This makes grade 600 suitable for everything from cryogenics to applications requiring resistance to temperatures up to 2000°F.
• Nickel Alloy 601. This engineering material is ideal for applications requiring resistance to heat and corrosion, high mechanical strength, and good metallurgical strength.
• Nickel Alloy 625. Alloy 625 offers high strength, ease of fabrication, and outstanding thermal fatigue strength. It is commonly used by industries such as nuclear power production, aerospace, marine, and more.
• Nickel Alloy 718. This high-strength nickel-chromium alloy offers great corrosion resistance, oxidation resistance, and ability to withstand a wide temperature range. Due to its unique properties, it is used for applications such as jet engines, cryogenic storage tanks, and more.
• Nickel Alloy X-750. This cost-effective alloy provides high strength at temperatures up to 1500°F, excellent workability, and resistance to various corrosive materials. It is often used for aircraft structures, pressure vessels, jet engine parts, and more.
• Nickel Alloy 800H. This nickel-iron-chromium alloy provides resistance to high-temperature corrosion, oxidation, sulfidation, and carburization. Its ability to withstand prolonged exposure to high temperatures makes it ideal for petrochemical and chemical processing, heat treatment equipment, and more.
• Nickel Alloy 825. The combination of molybdenum, copper, and titanium gives this alloy enhanced corrosion resistance in harsh environments. This makes it suitable for industries such as chemical processing, oil & gas, marine, pollution control, and acid production.
• Nickel Alloy C22. This alloy offers resistance to stress corrosion cracking, intergranular attacks, crevice corrosion, pitting, and corrosion. It is frequently used in industries like chemical processing, pulp and paper processing, pollution control, and oil & gas.
• Nickel Alloy C276. This nickel-molybdenum-chromium wrought alloy is ideal for use in applications requiring protection from aggressive corrosion and localized corrosion attack.

Alloy Steel

The most desirable properties of alloy steels are corrosion resistance, machinability, hardness, and strength. Manufacturers can enhance specific properties by combining carbon steel with alloying elements, which may include silicon, cobalt, titanium, manganese, and more. These alloying elements comprise approximately 5% of the finished alloy steel. Alloy steel is often found in pipes, as well as in heating elements for many household appliances.

Common grades of alloy steel include:

• Grade 4140 — Chromium Molybdenum Steel
• Grade 4340 — Nickel-Chromium-Molybdenum Steel
• Grade 6150 — Chromium Vanadium Steel
• Grade 8620 — HSLA -Nickel-Chromium-Molybdenum Steel

Stainless Steel Alloy

Any steel containing more than 10% chromium is classified as stainless steel. Properties of stainless steel alloys include good formability, corrosion resistance, and weldability. The versatility of these alloys makes them popular across a wide range of applications, from surgical instruments and industrial equipment to everyday cookware.

Common grades of stainless steel alloy include:

• Type 304. This popular grade is durable and resistant to chemicals and corrosion. Common applications include architecture and food processing.
• Type 316. This grade contains molybdenum, giving it a higher resistance to corrosion and different types of deterioration.
• Type 410. Although it does not have the same levels of corrosion resistance as other grades, Type 410 offers high levels of strength at an affordable price point. It is also heat treatable.
• Type 430. This type of stainless steel is popular for aesthetic applications due to its corrosion resistance.

Aluminum Alloy

Manufacturers may add a number of different alloying elements to aluminum, including copper, magnesium, iron, and zinc. The primary property of aluminum alloy is its strength, although various other properties, such as thermal conductivity and corrosion resistance, can be enhanced through the use of certain alloying elements. Common applications for this material include storage tanks, home appliances, and utensils. It is also found in a range of applications within the architecture and construction industries.

Common grades of aluminum alloy include:

• 5052. This grade of aluminum alloy is highly resistant to corrosion from saltwater, making it an ideal choice for marine applications. It also offers high levels of strength and weldability.
• 6061. Unlike type 5052, this aluminum alloy is heat treatable. It provides high levels of weldability and workability, making it popular throughout the construction and architecture industries.
• 6063. Popular for aluminum extrusions, this grade is highly favored within the architectural industry thanks to its high tensile strength.
• 5086. This alloy offers high strength, corrosion resistance, and electrical conductivity. Popular applications include shipyards, cryogenics, tank cars, missile components, and drilling rigs.
• 7075. This high-strength aluminum alloy offers good stress-corrosion cracking resistance. Its toughness and strength-to-weight ratio make it a popular choice for aerospace applications.

Copper, Brass, and Bronze Alloys

Due to their color, bronze, brass, and copper are all known as red metals. Although brass and bronze are both alloys, copper itself is a pure metal that can be combined with other materials. Bronze combines copper and tin, while brass combines copper and zinc.

Copper is highly durable, conductive, and resistant to bacteria, corrosion, and impacts. Brass and bronze are similar to copper but also have very high melting points and slight brittleness. These materials are the optimal choice for a wide range of applications, including pipes, electrical systems, and musical instruments.

Copper

Grades of copper include:

• Alloy 101. This is a popular choice for applications requiring ductility and conductivity, as it contains no oxygen.
• Alloy 110. This grade of copper offers malleability, ductility, and incredibly high conductivity.
• Alloy 122. Although it offers many of the same properties as Alloy 110, Alloy 122 also provides high levels of weldability and formability.
• Alloy 145. Also known as tellurium copper, Alloy 145 is very machinable and highly conductive.

Brass

There is a wide range of brass grades available, including:

• Alloy 260. Known for its cold working properties, this alloy is often found in hardware and automobiles.
• Alloy 272. This alloy contains 33% zinc and is most often utilized in architectural and industrial applications.
• Alloy 330. With its low lead content, Alloy 330 is highly machinable and provides good cold working properties.
• Alloy 353. Sometimes known as clock brass, this alloy offers high levels of machinability and is ideal for precision parts.

Bronze

Common grades of bronze include:

• Alloy 932. This option contains high levels of lead and is often found in non-pressure components and washers.
• Alloy 954. This versatile aluminum bronze alloy is utilized across a wide range of industrial equipment.

When manufacturing a product, selecting the appropriate alloy is imperative. There are a wide array of factors to consider when choosing the appropriate material, including:

• Desired physical properties
• Desired mechanical properties
• Cost
• Service
• Fabrication
• Desired surface properties

With so many options to choose from, it is possible to find an alloy with properties that perfectly suit the needs of your project. Working with a metal alloy professional eases the decision-making process, narrowing down the options and ensuring that you select the optimal metal alloy.