Introduction
Everyone in manufacturing knows that titanium is one of the most premium metals. Titanium has a host of excellent properties. It is lightweight but stronger than you’d expect. It has great durability, bio-compatibility, and corrosion resistance. The caveat is its cost. You see, it is quite expensive to work with titanium. The cost of machining a titanium workpiece can be three times that of aluminum! Why is titanium so costly to work with? Let us remove the curtain from this mystery for you.
Basic Properties and Applications of Titanium – High Demand, Low Supply
Titanium is employed in several important industries, such as aerospace, marine, and manufacturing. These industries require high-performing tools and devices, so they emphasize a material’s strength-to-weight ratio. Titanium is also chemically inert and non-toxic, making it suitable for medical equipment. On top of this, its supply is limited to a few countries, like China and Russia. All these factors lead to an increase in titanium cost.
Titanium Grades and Prices
Grades are a system of classifying the different chemical compositions in which titanium is available. Each grade has unique characteristics such as hardness, flexibility, corrosion resistance, etc. Let us discuss some common titanium alloys and their properties:
Grade 5 Titanium – Titanium 6Al-4V
Titanium grade 5 is an alloy containing 6% aluminum and 4% vanadium. It is widely available commercially and offers great strength and toughness. This metal finds application in aeronautical fields, marine settings, chemical plants, and healthcare.
Grade 6 Titanium – Titanium 5Al-2.5Sn
This titanium alloy offers good temperature coefficients due to its 5% aluminum and 2.5% tin composition. Manufacturers supply it in various shapes, such as wires, sheets for forging, bars, and plates. Titanium of grade 6 is often used in aviation and automotive sectors.
Grade 9 Titanium – Titanium 3Al-2.5V
This form of titanium has moderate strength and is mainly used in piping systems. Compared to other grades, it falls intermediate between grade 4 and grade 5. However, it is tougher and more corrosion-resistant. This titanium alloy has excellent temperature coefficients and can withstand more heat than grades 1 to 4. It is also better suited for cold rolling.
Titanium Alpha-Beta Alloys
Titanium alpha-beta alloys are formed by combining aluminum, vanadium, and tin traces. Ti-6Al-6V-2Sn is one such alloy offering good heat treatment and welding properties. They can have medium to high strength levels. They have limited cold forming but excellent hot forming qualities. These alloys are commonly used in aircraft turbine parts, marine equipment, chemical processing plants, etc.
The prices of these titanium alloys vary depending on their purity, alloy composition, and the complexity of the processing technology. Grade 5 (Ti-6Al-4V) is the most common α+β type titanium alloy. Its price is relatively moderate, about 35-45$/kg. Grade 6 (Ti-5Al-2.5Sn) is slightly more expensive than Grade 5. Grade 9 (Ti-3Al-2.5V) is a more economical α+β type titanium alloy with a relatively low price. Among them, the price of aviation grade is generally 20-30% higher than that of industrial grade. It is worth noting that the same grade of titanium alloy will also have significant price differences depending on its final use and processing technology.
If you want to learn more about the titanium alloys used in the CNC industry, head to our Custom Titanium CNC Service page.
Why is Titanium So Expensive?
1. Sourcing the Raw Material Titanium
The first difficulty is titanium procurement. Sure, it is the ninth most commonly found metal on Earth. However, it does not exist in a pure state. It is found in rutile and ilmenite, which are titanium ores.
Extracting titanium from its ores is more complex than you’d think. It cannot be done using carbon because the chemical reaction forms a brittle compound. Titanium also has a high melting point, making the process energy-intensive.
Mining titanium from its ores is a complex task. It is done using the Kroll Process. The metal is transformed into a porous shape called a titanium sponge. The titanium sponge is then slowly melted to produce metal ingots. The energy consumed in this process accounts for 30% of the total cost. A significant amount of titanium is lost during the refinement process. It is estimated that 11 kg of titanium ore on refinement produces about 1 kg of pure metal.
2. Tooling and Equipment Requirements for Titanium Processing
In terms of pure strength, high-quality steel is better than titanium. However, titanium’s prowess shines when subjected to temperature. Steel can only operate up to 1500 degrees Celsius. However, titanium can withstand temperatures up to 1800 degrees Celsius.
Titanium does not perform better than steel at just high temperatures. Steel is prone to shattering in sub-zero conditions, while titanium is not. However, titanium is better than steel when it comes to flexibility. It can flex and bow under the pressure of CNC machines.
Is titanium expensive due to these factors? Yes. Due to its hardness and abrasiveness, tools wear out faster. The adjustments needed to make titanium parts shine are crucial and complex. The tool selection process is also complicated. This adds to the expense of an already costly raw material.
3. Thermal Management and Machine Wear When Cutting Titanium Metal
Why is titanium so expensive? Another big reason is the heat generated during titanium cutting. Now, metals like iron and aluminum have great thermal conductivity. This means that the heat of the cutting tool gets dissipated. Titanium, however, has poor thermal conductivity. This causes the workpiece to heat up. Left unattended, this can cause damage to the machine.
Several techniques are employed to dissipate this heat in CNC machines. When dealing with titanium, machines operate at lower RPMs. Using a chip load is another alternative. When working with titanium, high-pressure coolants and lubricants are recommended. Naturally, these add to the cost of manufacturing.
4. Galling and Chemical Reactivity during Titanium Machining
During titanium operations, atmospheric gasses can react with the surface metal. The resulting oxidation may cause impurities in the metal. It can reduce component strength and make it prone to corrosion.
Additionally, cutting titanium is challenging due to its gummy nature. Due to its low elasticity, it can easily stick to the cutting tool. This can damage parts of the CNC machine. It is also susceptible to galling, which can threaten its outer finish.
5. Production Time of Titanium Parts
Titanium parts production consumes more time than other metals. Its hardness, strength, and low elasticity make it difficult to operate CNC machines at high speeds. This difficulty means the operator must spend more time overseeing the operation. This leads to longer machining times, increasing electricity and labor costs.
6. Post-Processing and Waste Management
Due to their distinctive physical and chemical properties, titanium parts must undergo significant post-processing. Additional work, such as surface finishing or heat treatment, may be required after production. This results in an increase in the manufacturing cost of titanium products.
Waste management and cleaning of tools after titanium production is also challenging. Titanium is a paramagnetic material. This characteristic means that it has weak magnetic properties. Therefore, its dust and filings cannot be cleaned using a magnetic device. This means other cleaning tools like mechanical brushes or water jets may be required. Head over to this article to learn more about titanium’s magnetic properties.
7. Certifications and Quality Assurance
Raw materials in critical industries such as aeronautics and healthcare require stringent quality norms. Manufacturers are required to maintain detailed specification sheets for their products. Titanium is widely used in many such industries. The need for certifications and licenses increases metal cost and procurement time.
If formally licensed raw material is not a concern, go for non-certified titanium. This kind of titanium has no specification sheet. It is available on an as-is basis. It is significantly cheaper than certified titanium. Some suppliers can also provide you with lab-certified titanium. This metal is verified by a third-party testing facility. It costs more than non-certified titanium but is still more affordable than certified titanium.
Frequently Asked Questions
Is CNC machining using titanium difficult?
Yes, CNC machining with titanium is challenging. Titanium is a hard metal with poor heat conductance, causing the workpiece to heat up during cutting and drilling. Due to a low modulus of elasticity, it can also stick to the cutting tool, causing further difficulties. However, working effectively with titanium with the right tools and procedures is possible.
What are the advantages of using titanium?
Titanium is hard and durable. It is 40% lighter than steel while offering comparable strength. Its corrosion resistance, biocompatibility, and temperature resistance make it immensely useful. Due to this, titanium is one of the most premium metals to make machine parts.
What are the grades of titanium?
Titanium grades are a method of categorizing the various chemical compositions in which titanium is available. Grades 1 through 4 are pure titanium forms. Grades 5 and above are titanium alloys with other metals like aluminum, vanadium, and tin. Each grade represents materials that have different properties. Depending upon your usage, availability, or rarity, the price of each grade may differ.
What are the factors that affect the price of titanium during CNC machining?
Factors such as metal grade, part complexity, machining time, and tool wear influence the price of titanium machining. Due to the potential for excessive heat generation, high-pressure coolant may be required. Additionally, the CNC machine must be operated at a lower RPM, increasing production time. Scrap collection and waste management are also challenging. All these things compound the price of titanium machining.
How can the expenses of titanium machining be decreased?
Efficient planning is the key to reducing costs while working with titanium. During pre-production, focus on optimal design. Reduce unnecessary geometrical features that may impact machining time. Choosing an appropriate titanium grade is also very important. Different grades have different properties like machinability and performance. Evaluate which suits you best according to the parts you need to produce.
Conclusion
Titanium is immensely useful for its strength, durability, corrosion resistance, and thermal tolerance. But like it’s said, all good things come with a price. Its immense demand, complex procurement, and difficult machining make it one of the most expensive materials to work. This does not mean that titanium production is not profitable. You can quickly begin producing premium titanium parts with proper planning and preparation. This will elevate your business and help you reach the status of a top-tier titanium manufacturer. For professional consultation on titanium-ready CNC machines, contact our team of professionals. We would be happy to help you.