If you’ve ever wondered how high temperature working mechanical parts can withstand extreme heat without melting, then this guide is for you. In most cases, the industrial applications of these parts require them to withstand such temperatures without losing their structural integrity and strength, while avoiding deformity. Industries such as aerospace, and power generation plants make use of these parts to avoid any failures as such malfunctions can result in catastrophic incidents. Well, there are several material options for such parts and they include, stainless steel, titanium, nickel alloys, and cobalt alloys.
Their individual unique properties make each metal fit for a specific purpose. such properties include anti-corrosion, heat conduction, and hardness. Let’s go deeper and further understand these mechanical parts. Shall we?
II. Metals for High-Temperature Working Mechanical Parts: Property Considerations
If you are a manufacturer of high temperature working mechanical parts, for things like mold manufacturing, then choosing the right material for you should be a given. High-temperature mechanical parts require careful consideration of several important properties, the most important ones of which are highlighted below.
- Melting point: This might seem obvious, but it’s crucial to choose a metal with a melting point higher than the temperature at which your part will be used. Otherwise, what you’ll have is a big melty mess. It is for this reason tungsten and titanium are recommended choices for such qualities. They boast of some of the highest melting points among all metals.
- Strength at high temperatures: Equally as important as the melting point is the strength at high temperatures. Some metals such as Aluminum lose their strength at certain temperatures. Therefore, you should consider metals that retain their strength at temperatures as high as 1000C. One such metal is nickel-based alloys.
- Resistance to oxidation and corrosion: Metals are quick to corrode when exposed to high temperatures. This is because they react with oxygen and become brittle.
However, for a long-lasting and durable metal that is neither susceptible to corrosion or oxidation, we advise that you opt for metal with high corrosion and oxidation resistance. This move most often will boost performance. One good example is stainless steel. It is high in chromium which creates an oxide layer that protects it from corrosion.
- Thermal conductivity: The ability to conduct heat is another paramount feature you should consider. A highly thermal metal helps distribute heat away from parts. Among the many high heat conducting metals copper is agreeably the most efficient metal for heat conduction purpose.
- Ductility and toughness: Ductility is the ability of a metal to withstand stress without breaking or bending. Toughness on the other hand is determined by how much energy absorption it can take without breakage. Therefore, a metal that can withstand fracture, cracks, or breakage is highly advised. Especially when dealing with high temperatures.
All the parameters highlighted above are high priority consideration for experts and engineering design professionals at the early stages like during mold design before going into mold manufacture. Acquainting yourself with these properties will help you choose the most suitable material that can withstand the heat of operations during its working life.
III. Metals Suitable for High-Temperature Working Mechanical Parts
When it comes to extreme heat working conditions, different metals possess different capacities and capabilities. The properties they possess determine their application. Therefore, we have highlighted each metal and the qualities they possess below.
- Stainless steel – First in line is stainless steel. A versatile and widely used alloy that contains chromium, iron, and other elements. putting these elements together to form a material that is highly corrosion-resistant known as stainless steel. Moreso, stainless steel is affordable, easy to maintain, and durable. It’s often used in high-temperature applications because it retains its strength even at high temperatures, and it resists scaling and oxidation. And this makes it an ideal choice for the aerospace and automotive industries to make exhaust systems and engine components.
- Titanium – Titanium is a metal that possesses qualities such as being lightweight, strong, and highly corrosion-resistant. It has excellent strength retention at high temperatures and is often used in aircraft engines, gas turbines, and other high-performance applications where heat resistance is critical. In addition to its high durability, titanium is also biocompatible, which makes it a great choice for medical implants.
- Nickel-based alloys – Nickel-based alloys are metals known for withstanding high-temperature capacities of up to 10000C. in addition to this feat, it is highly corrosion resistant and has increased thermal stability. Qualities like this make it suitable for aerospace engines, gas turbines, and other high-temperature applications. Nickel-based alloys are one of the elements present in stainless steel.
- Tungsten and molybdenum – Two of the most resistant materials with respect to extreme heat are the refractory metals known as tungsten and molybdenum. These refractory metals have melting points that exceed 10000C or more, making them ideal for high-temperature applications such as furnace components, electrical contacts, and rocket nozzles. Tungsten can also be used in manufacturing light bulb filaments. This is due to its lightness when not combined with any other element. While molybdenum is a pocket-friendly metal with the qualities of a high-temperature capacity part.
- Refractory metals (e.g., niobium, tantalum) – Niobium and tantalum are another set of refractory metals that are suitable for extreme heat use cases like for furnace materials. Properties such as high thermal conductivity, resistance to chemical exposures, a high melting point of up to 30000C, and low thermal expansion make them one of the best forms of metal in high-temperature working mechanical parts. Some other applications for these metals include in the manufacture of nuclear reactors, airplane engines, rocket nozzles, and turbines. Niobium, due to its lightweight and durability, is likewise applicable in the production of medical equipment.
IV. Comparison of Metals
The importance of appropriate metal selection in high-temperature working mechanical parts cannot be overemphasized. For this reason, each metal must be carefully understood for proper application. To specify any metal requires an understanding of its strength and weakness that makes it fit for specific purposes and unfit food for others. Let’s compare some of the most commonly used metals in this field.
The first metal on the list is titanium. properties that include strength, ant-corrosion, and low density are what makes titanium unique. Titanium can withstand temperatures of over 6000C, and it is applicable in the aerospace industry where it is used as part of a component. Some of its strengths account for its drawbacks in other areas including low machinability and expensive production processes making it unsuitable for applications like rapid prototyping.
Next is stainless steel. Highly resistant to corrosion and outstanding resilience to oxidation induced by high temperature situations all make stainless steel one of a kind manufacturing material.
Stainless steel can withstand a high temperature of 8000C and is commonly used in the construction of aircraft parts and gas turbines. However, stainless steel can become brittle at higher temperatures over what it can take. Additionally, in comparison with other metals, it is relatively low. Especially with metals such as tungsten and nickel-based alloys that can withstand higher temperatures of over 10000C, stainless steel is no match.
Next on our list of metals is nickel-based alloys. These metals, like its contemporary titanium, have immense strength and are highly resistant to corrosion and oxidation. As mentioned above, nickel-based alloys can withstand high temperatures above 10000C. But just like titanium, they are quite expensive and hard to work with. They are majorly used for heat exchangers and chemical processing equipment.
Tungsten is a metal that presents the highest melting point of any metal. It can cope with a high temperature of more than 30000C. Its brittle nature makes tungsten difficult to machine with methods like CNC machining despite its high strength as often observed with most hard materials. Tungsten is typically used for electrical contacts such as light bulb filaments, and heating elements. Furthermore, due to its capacity to withstand high temperatures without deforming, it serves as a rocket engine nozzle as well.
We also have molybdenum. Molybdenum also has quite similar properties to tungsten, and similar drawbacks as well. Molybdenum is a strong metal with high-temperature capacity. It is also applicable in electrical parts production, rocket engines, and high-temperature furnace components. And like tungsten, it is also brittle, and working with it can be laborious.
In conclusion, before the selection of the metal appropriate for your purpose is made, these considerations need to be factored in. It is safe to say the application of metal determines the choice of metal. However, the properties of such metal must be properly understood. The strength of the metal at high temperatures, thermal conductivity, resistance to corrosion and oxidation, melting point, and toughness it is highly recommended that these qualities are present in your preferred metal. Conclusively, whether it’s the high strength of nickel-based alloys or the high-temperature resistance of tungsten, understanding the properties of each metal is crucial for making the right choice for your application.