Titanium is an important metallic element with the chemical symbol Ti and atomic number 22 on the periodic table. It has a silver-white metallic luster and possesses excellent properties such as high melting point, low density, high strength, and strong ductility. Titanium is a crucial industrial material. If you want to learn more about titanium, please continue reading below!
The Another Term for Titanium
Titanium has many outstanding advantages, such as: low density, strong ductility, and strong corrosion resistance, so it is also known as “miracle metal”, “space metal”, or “marine metal”.
The History of Titanium
In 1791, titanium was discovered in England by amateur geologist William Gregor. In 1795, German chemist Klaproth, referencing the name of the Titan deities from Greek mythology, named this new element “Titanium”. It wasn’t until 1910 that American chemist Hunter first obtained 99.9% pure titanium metal by reducing TiCl with sodium. In 1940, Luxembourg scientist Kroll also produced pure titanium using the magnesium reduction method. Since then, both the magnesium reduction method and the sodium reduction method have become industrial processes for titanium production.
The Color of Titanium
Titanium metal has the appearance of steel, with a silver-white or silver-gray luster, and it is a transitional metal.
What is Titanium Made Of ?
Titanium is widely distributed, accounting for about 0.44% of the Earth’s crust, and is found in all rocks, sands, clays, and other soils. However, because titanium readily reacts with oxygen, pure titanium is not found in nature; it mainly exists in the form of titanium dioxide. Titanium ores mainly include ilmenite and rutile, and pure titanium can be obtained through purification of these minerals.
How is Titanium Made?
Titanium is usually produced using the Kroll process. Firstly, titanium ore is heated to produce liquid titanium tetrachloride (TiCl4). Next, purification is done using fractional distillation. After distillation, molten magnesium is added to reduce it to “sponge” form. The sponge is then melted to form ingots, which are further processed into various mechanical products such as rods, plates, sheets, and tubes. Finally, these mechanical products are further processed and shaped, and surface treatment is applied as needed to optimize the product.
What are the Main Types of Titanium?
Titanium has two types of polymorphic structures, namely the α phase and the β phase. Based on the polymorphic characteristics of titanium, titanium alloys can be divided into the following three major categories: α titanium alloys, β titanium alloys, and α+β titanium alloys.
Alpha Titanium Alloy
Alpha titanium alloys are further divided into full alpha alloys and near-alpha alloys. They are single-phase alloys composed of alpha phase solid solution. They exhibit good cold and hot working properties, stable structure, and strong oxidation resistance.
Beta Titanium Alloy
Beta titanium alloys are further divided into stable beta alloys, metastable beta alloys, and near-beta alloys. They are single-phase alloys composed of beta phase solid solution and exhibit excellent strength characteristics, achieving high levels of strength. They also possess strong corrosion resistance and weldability.
α+β (Alpha+Beta) Titanium Alloy
It is a two-phase alloy with good comprehensive properties, including stable structure, good toughness, good plasticity, and high-temperature deformation resistance. The alloy can be strengthened through processes such as hot pressing, quenching, and aging treatment.
What are the Common Grades of Titanium?
Grade 1
Grade 1 commercial pure titanium is the softest and most ductile type of titanium. It offers maximum formability, excellent corrosion resistance, and high impact toughness. It is the preferred material for applications requiring ease of forming and is commonly used in the aerospace, automotive, and power generation industries.
Grade 2
Grade 2 commercial pure titanium is the most commonly used commercial pure titanium, with moderate strength and excellent cold forming properties. Compared to other commercial pure titanium grades, Grade 2 titanium is slightly weaker than Grade 3 but stronger than Grade 1, while still offering corrosion resistance. Due to its corrosion resistance, it is commonly used in the marine, medical, power generation, and petroleum industries.
Grade 3
Grade 3 titanium is the least used among commercial pure titanium grades, but it does not diminish its value. It has high strength, good corrosion resistance, and weldability. Its strength is higher than Grade 1 and Grade 2, but its ductility is lower than the other two grades. It is commonly used in the marine industry, aerospace, and chemical processing industries.
Grade 4
Grade 4 titanium is considered the strongest among commercial pure titanium grades, known for its excellent corrosion resistance, good formability, and weldability. It is commonly used in aerospace, chemical processing, and medical industries for applications such as airframe structures, heat exchangers, surgical hardware, etc.
Grade 5 or Ti 6Al-4V
Grade 5 titanium, also known as Ti6Al-4V, is referred to as the “workhorse” of titanium alloys and is the most commonly used among all titanium alloys, accounting for 50% of the total global titanium usage. This alloy is characterized by its lightweight, extremely high strength, heat resistance, corrosion resistance, and formability. Therefore, it is highly favored in the aerospace industry for manufacturing engines, structural components, and fasteners.
Grade 6 or Ti 5Al-2.5Sn
Grade 6 titanium has extremely strong stability and maintains good weldability and strength even at high temperatures. It also exhibits excellent processing properties. It is commonly used for turbine engine casings, aircraft components, and chemical processing parts.
Grade 7
Grade 7 titanium is similar to Grade 2 titanium, except for the addition of the interstitial element palladium (in the range of 0.12% to 0.25%), which enhances its ability to resist crevice corrosion. Grade 7 also exhibits excellent weldability and is the most corrosion-resistant among all titanium alloys. It is commonly used in chemical manufacturing, seawater desalination, and power production.
Grade 11
Grade 11 titanium, also known as CP Ti-0.15Pd, is a commercial pure titanium similar to Grade 1 and Grade 2, with the addition of a small amount of palladium to enhance corrosion resistance. It can be used to prevent crevice corrosion and reduce acids in chloride environments. Grade 11 titanium also exhibits high ductility, cold formability, useful strength, impact toughness, and excellent weldability. It is commonly used in chemical processing and heat exchangers.
Grade 12 or Ti 0.3-Mo 0.8-Ni
Grade 12 titanium, also known as Ti 0.3 Mo 0.8 Ni, is a highly corrosion-resistant alloy containing small amounts of nickel and molybdenum. These elements enhance corrosion resistance and increase alloy strength. It is commonly used in applications such as ships or offshore drilling platforms.
Grade 23 or Ti 6AL-4V ELI
Grade 123 titanium, also known as Ti 6Al-4V ELI, is characterized by high ductility, high strength, lightweight, corrosion resistance, and high toughness. It is the preferred choice for dental and medical applications.
Which Grade of Titanium is Best?
Grade 5 (Ti 6Al-4V) titanium is known as the “workhorse” because it accounts for half of the demand for titanium. Due to its wide range of desirable properties, it has become the most commonly used titanium grade. Grade 5 titanium has high strength, high ductility, strong corrosion resistance, excellent thermal stability, and is easy to process and shape, making it widely used in industries such as aerospace and marine.
What is the Cost of Titanium?
The cost of commercial pure titanium is approximately $23-25 per kilogram, while the cost of titanium alloys is approximately $27-30 per kilogram.
Which is the Cheapest Titanium Grade?
Currently, Grade 1 titanium is relatively cheaper in price, mainly depending on specific application requirements and market supply conditions.
What Grade of Titanium is Used for Anodizing
Both Grade 2 and Grade 3 titanium can be used for anodizing treatment.
What are the Properties of Titanium?
Below are the physical and chemical properties of titanium:
Physical Properties
Density: 4.5 grams/cubic centimeter
Color: Silver-white metallic luster
Strength: The strength of titanium depends on the grade of titanium and the concentration of its alloying elements.
Abundance: Titanium is the ninth most abundant element in the Earth’s crust, almost present in all rocks and sediments.
Temperature Resistance: Titanium can withstand higher and lower temperatures compared to stainless steel and aluminum.
Ductility: The ductility of titanium ranges from 6% elongation (Ti-3Al-8V-6Cr-4Zr-4Mo) to 25% (commercially pure Grade 1).
Chemical Propertie
Oxidation: Due to its high oxidation potential, titanium does not exist in its pure form in nature but rather in the form of oxides in rocks and minerals.
Reactivity: It reacts with acids and halogens at high temperatures but does not react with alkalis at all.
Corrosion Resistance: Titanium has extremely strong corrosion resistance, resisting corrosion from acids, alkalis, and seawater, because oxygen molecules combine with titanium to form titanium oxide.
Machinability: It is easy to process into various shapes of products, such as rods, plates, pipes, etc.
Titanium Metal Fabrication Process
The Kroll process is used to convert crude titanium into titanium metal. The steps of this process include extraction, purification, sponge production, alloy manufacturing, as well as shaping and forming.
Extraction
High-grade concentrates are extracted from raw ores such as ilmenite and rutile and sent to factories for processing. After pre-treatment to remove iron content, ilmenite is placed into a fluidized bed reactor containing chlorine and carbon and heated to 900°C. During the chemical reaction, titanium tetrachloride is produced along with carbon monoxide. Titanium tetrachloride contains impurities that need to be removed to prepare titanium dioxide.
Purification
Titanium tetrachloride undergoes high-temperature vacuum distillation for purification. The metal produced during the extraction process is heated in large distillation tanks. The purification process uses fractional distillation and precipitation to separate impurities. Due to the different boiling points of various elements, during the distillation process, various elements are removed when they reach their boiling points. The removed impurities include vanadium, silicon, magnesium, zirconium, and iron.
Sponge Formation
With the formation of sponge, purified titanium tetrachloride is poured into stainless steel reaction vessels in liquid form. Magnesium is added, and the mixture is heated to 1100°C to react with chlorine to produce magnesium chloride. Argon gas is pumped in to remove air, preventing reactions with oxygen and nitrogen. The produced titanium is extracted through drilling and treated with a mixture of water and hydrochloric acid to remove excess magnesium and magnesium chloride. The resulting titanium is in sponge form.
Alloy Creation
Pure sponge titanium is mixed with various alloys and scrap metals to manufacture alloys. After melting and mixing the metals in appropriate proportions, the chunks are compacted and welded to form sponge electrodes. These are melted in a vacuum arc furnace to form ingots for further processing into various industrial and commercial products.
Shaping and Forming
Ingots are removed from the furnace, inspected, packaged, and transported for manufacturing titanium alloy products. The properties of each ingot are inspected to ensure they meet customer requirements. The ingots undergo different processes such as welding, shaping, casting, forging, and powder metallurgy during the product manufacturing process.
What are the Benefits of Titanium?
High Strength
Titanium possesses excellent strength, making it one of the strongest metals on the periodic table. Due to its low density, titanium is also very lightweight.
Corrosion Resistance
Titanium readily reacts with oxygen, forming a thin oxide layer on its surface, which provides natural corrosion resistance.
Biocompatibility
Titanium is non-toxic and biocompatible with both humans and animals. Therefore, titanium is frequently used in the medical and dental industries.
Low Thermal Expansion Coefficient
Titanium has a low thermal expansion coefficient, resulting in minimal expansion and contraction at extreme temperatures, leading to higher structural stability.
High Melting Point
Titanium has an extremely high melting point (approximately 1668°C), making it highly suitable for high-temperature applications such as foundries and turbine jet engines.
Excellent Manufacturing Possibilities
Despite being a very strong metal, titanium is also soft and ductile. This allows titanium components to be manufactured using various manufacturing processes.
What are the Limitations of Titanium?
Expensive
Titanium is considered a rare metal, and its purification is both expensive and complex.
Difficult to Shape
Advanced machinery and specialized equipment are required to shape it into useful forms.
Reacts at High Temperatures
This makes the manufacturing of pure titanium and titanium alloys cumbersome and highly controlled. Titanium production must be conducted in strictly controlled anaerobic environments.
Poor Thermal Conductivity
Titanium is a material with poor thermal conductivity, making it difficult to process.
What are the Applications of Titanium?
Aerospace
Titanium alloys are valued in the aerospace industry for their high strength-to-density ratio, corrosion resistance, and ability to withstand moderate temperatures without creep.
Automotive
Titanium is favored in the automotive industry due to its low density, high strength-to-weight ratio, corrosion resistance, and heat resistance.
Industrial
Titanium is widely used in industrial environments due to its high strength, corrosion resistance, lightweight, and durability. Its applications include heat exchangers, valves, pipes, and connecting rods.
Medical
Titanium is non-toxic and biocompatible with human bones, making it highly suitable for medical applications. It has inherent properties for bone integration and can be used for dental implants that can last for more than 30 years, which is also useful for orthopedic implant applications.
Health and Environmental Effects of Titanium Metal
Health Effects of Titanium
Titanium metal is a biocompatible material with excellent biocompatibility and is non-toxic. It is commonly used in medical instruments and implants and does not have harmful effects on the human body.
Environmental effects of titanium
Titanium does not release toxic substances, thereby avoiding adverse environmental impacts. However, during the production process of titanium, some waste or exhaust emissions may be generated. Nevertheless, with effective management and proactive treatment measures, the environmental impact can be minimized to the greatest extent possible.
FAQs
Is Titanium Rust Proof?
Yes, titanium alloys have excellent corrosion resistance and can withstand the erosion of many chemicals.
Is Titanium Magnetic?
Generally speaking, pure titanium is typically non-magnetic because the crystal structure of pure titanium does not support magnetism. However, certain titanium alloys may exhibit magnetism, depending on the types and concentrations of alloying elements.
Is Titanium Bulletproof?
Yes, titanium has bulletproof capabilities for handguns and hunting rifles, but for military-grade equipment, titanium is not bulletproof.
What Is the Difference Between Titanium and Aluminum?
Material Characteristics
Titanium has higher strength and corrosion resistance than aluminum, while also being lighter than aluminum, but it is more costly. Aluminum is a lightweight metal with good thermal and electrical conductivity and lower cost compared to titanium.
Applications
Titanium is commonly used in applications requiring high strength and corrosion resistance, such as aerospace and medical devices. Aluminum has a wider range of applications, including aerospace, automotive, construction, and electronics.
Processing Difficulty
Due to its higher strength and corrosion resistance, titanium is more difficult to process, requiring higher-level processing equipment and techniques. In contrast, aluminum is relatively easy to process and can be machined and formed using conventional methods.
What Grade of Titanium Is Used for 3D Printing?
Grade 5 titanium, also known as Ti-6Al-4V, is commonly used in 3D printing due to its excellent strength-to-weight ratio and biocompatibility.
Conclusion
This article introduces what titanium is, its developmental history, types of titanium, classification of titanium grades, basic information about its characteristics, etc. The formation process of titanium alloys is primarily explained using the Kroll method, along with the advantages and disadvantages of titanium and its application areas.
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