CNC machining operation
Steel and Titanium are the two most common CNC materials used in various machining projects. These two metals are well known for their outstanding mechanical strength and toughness. The comparison of Steel and Titanium CNC machining is a worthy discussion since these materials have many alloys and versatile properties.
We will discuss the differences between Titanium and Steel CNC machining based on their properties, machinability, advantages, disadvantages, applications, CNC machining conditions, and many more.
Steel vs Titanium: Common Alloys Machining
Several alloys of Titanium and steel are used in CNC machining projects. You can check the table below for a comparison of the machining of these two materials. You can also check our Steel Machining and Titanium Machining service page for more details.
| Materials | Applications | Alloys | Tolerances | Wall Thickness | Part Size | Strengths |
| Alloy Steel | The low-cost and high-strength parts for construction, automotive, defense maritime, tooling, and many more industries from 3 axis & 5 axis CNC machines) | Alloy Steel 4130 Alloy Steel 4340 Steel (4140 Alloy) Steel (1018 Low Carbon) Zinc-Galvanized Low-Carbon Steel Carbon Steel (1045)… |
Not lower than ±0.125mm (±0.005″) based on the drawing ( ISO 2768) | Minimum 0.75 mm (~0.03”); It might vary based on alloy type and size of the part) | 200 x 80 x 100 cm | High mechanical strength, toughness, resistance to wear and fatigue, and sturdiness |
| Titanium | Strength in Automotive, aerospace, and medical parts | Grade 1 Titanium Grade 2 Titanium Grade 5 Titanium（TC4, Ti6Al4v） |
Not lower than ±0.13mm (±0.005″) based on the drawing ( ISO 2768) | Minimum 0.75 mm (~0.03”); It might vary based on alloy type and size of the part) | 200 x 80 x 100 cm | 40% more strength-to-weight ratio than steel, Excellent corrosion resistance, low thermal expansion, and biologically inert |
Over 100 varieties of steel are available for CNC machining projects. However, these varieties come into four fundamental categories.
Steel Alloys
- Carbon steel
Carbon steel contains approximately 2-3% of carbon in the composition. The hardness depends on the carbon % and higher the hardness as carbon increases. It offers high machinability when it comes to processing with CNC technology, which decreases with the increasing amount of carbon content. Some popular grades under this category are 1010, 1018, 1030, 1040, and 1080.
- Alloy steel
As the name suggests, it is the combination of steel with other different alloying elements, such as nickel, manganese, copper, vanadium, chromium, tungsten, and other metals. The inclusion of these materials makes alloy steel highly corrosive resistance, wear-resistant, and maximizes strength and hardness. Some popular alloy steel grades include 4130, 4140, 4340, and 6150. It offers excellent accuracy and is simple to machine.
- Stainless steel
Stainless steel involves 10-20% chromium in the composition, which contributes to strength and provides a glossy silver appearance. It is more costly than earlier grades, has high corrosion resistance, and is less machinable. Some popular stainless steel grades include 303, 304, and 316.
- Tool steel
Tool steels are usually hardened and have the lowest machinability among the four classes of steel. The applications of this steel involve creating cutting, shaping, and other tools. There are six groups of tool steels, water-hardening, cold-work, shock-resisting, high-speed, hot-work, and particular purpose (Tool Steel | The Four Types of Steel, 2015).
Titanium Alloys
Titanium is a metal that is lightweight, robust, long-lasting, and remarkably resistant to corrosion. Different industries rely on titanium CNC machining for precise parts.
Titanium is a lightweight, strong, durable, and highly corrosion-resistant metal. It offers superior toughness and hardness along with a low coefficient of friction and wear resistance. Two primary alloys of Titanium used in CNC machining operations include Ti-6Al-4V and Ti-6Al-4VEli. The first is renowned for superior strength, and the second is for bio-compatibility.
Titanium is categorized into grades 1, 2, 3, 4, 7, and 11. The first four grades are considered the pure alloy grades, while the next three are alloy grades.
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Carbon steel vs. titanium
Carbon steel and titanium are two materials that are often compared due to their unique properties.
- Carbon steel is an alloy made from iron and carbon and is known for its durability and strength. It is often used in construction, engineering, and manufacturing due to its ability to withstand high stress and strain.
- Titanium, on the other hand, is a lightweight and corrosion-resistant metal that is often used in aerospace and medical applications. Unlike carbon steel, titanium is biocompatible, which makes it suitable for use in implant devices and other medical applications.
In terms of strength, titanium is stronger than carbon steel but is also more expensive. Carbon steel is more readily available and easier to work with, making it a more cost-effective choice for many applications. Both materials have their own advantages and disadvantages, and the choice between the two depends on the specific requirements of the project.
Which Has the Higher Machinability, Steel or Titanium?
CNC machining of steel
Machinability is a parameter of the subtractive manufacturing process that refers to how easily it can remove the material during machining operations, such as milling, turning, drilling, and others.
It is a crucial measurement to ensure the success of the CNC machining project for any particular material. The elastic properties play a significant role in machinability since the less elastic material quickly gets deforms. Additionally, hardness is another attribute that affects machinability.
Titanium is a hard metal and has low elasticity. Therefore, it is less machinable than steel. It requires several considerations and specialized machining tools to process with CNC machining. On the other hand, steel is more elastic than Titanium and offers better machinability.
Related:
Machinability of Material and Relation with CNC Machining
Comparison: Physical & Mechanical Properties
Both materials are popular in CNC machining projects because of their strength and toughness. Let’s compare the physical and mechanical properties.
Strength-to-weight ratio: Titanium has a high strength-to-weight ratio because of its low-density character. Comparing Titanium with steel, It provides the same strength as steel at 40% of its weight.
Corrosion resistance: Titanium offers more resistance to corrosion than steel and its alloys. Steel is more reactive towards acids, alkalis, and industrial chemicals, whereas Titanium is stable with these chemicals. However, it can be reactive to concentrated acids at high temperatures.
Electrical conductivity: Steel allows current flow more easily than Titanium because of its lower electrical resistance. The poor conductivity of Titanium makes it a fair electrical resistor.
Thermal conductivity:The thermal conductivity of steel is higher than that of Titanium and its alloys, and it will be wise to choose steel CNC machining for thermal applications. Steel can absorb and transfer heat better than Titanium.
Hardness: Hardness is the significant mechanical property of any engineering material. It determines the wear resistance, deformation, etching, and other aspects. Choosing the material for a CNC project requires consideration very carefully. The titanium oxide layer, which grows on Titanium, creates a rigid surface that can withstand the most penetrating forces. However, steel can match the hardness of Titanium with the heat treatment process.
Durability: Titanium is superior to steel when it comes to durability. It is nearly 2 to 4 times stronger than steel, depending on the alloy type. If CNC machined parts get care over scratching and a suitable surface finish, they can last for an extensive period.
Mechanical strength: You might think that Titanium is decisive regarding yield strength, but steel has more tensile strength. Although, Titanium is stronger based on per unit mass. It is better to choose steel for overall strength and Titanium for mass-per-unit strength. Similarly, steel offers high tensile and shear strength, but Titanium is a good choice for per-unit-mass strength.
Thermal stability: Titanium parts can work at high temperatures compared to steel. It is wise to choose for thermal applications. The melting of Titanium is 1668±10°C, whereas steel is converted to liquid at around 1370 °C (Hayes, 1956).
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Comparison of Applications
CNC machining of Titanium and steel both have a wide range of applications across several industries. Let’s compare them more closely.
| Steel CNC machining | Titanium CNC machining |
| Automotive: Springs, fuel tanks, chassis, wiper blades, bumpers, tailpipe, collector, floor, muffler, seat belt windshield, fasteners, and many more. | Aerospace: Engine blades, landing gear, shafts, interior structures, compressor wheels, connecting rods, engine compartments, and many more. |
| Architecture: tubes, plates, reinforcing bars, interior decoration, and more. | Medical: The biocompatibility of Titanium makes it ideal for Bone growth stimulators, spinal fusion devices, bone plates, orthodontics, and fake body parts. |
| Food processing: Cookware, commercial kitchen wares, brewing beer, meat processing, food dry systems, and more. | Marine: deck, shackles, snap hooks, pressure vessels, submarine probes, and more. |
| Medical: Lab equipment, surgical implants, and diagnosis devices. | Automotive: Frames, fasteners, mufflers, exhaust Pipes, engine valves, load-bearing springs, and many more parts. |
| Defense: Handguns, pistols, structures for military vehicles, and more. | Others: oil & gas, construction, architecture, jewelry, sports, and EV. |
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Comparison of CNC Machining Variables
| Steel CNC machining | Titanium CNC machining |
|
Hard steel and carbide tools Low Carbon Steel 120-170 ft. /min Medium Carbon Steel 100-120 ft. /min Alloy Steel 100-120 ft. /min |
Carbide tools with a diamond tip 200 m/min Source: (Troublesome Titanium – Tips on machining this tough material, 2014) |
Comparison of Surface Finishing Options
CNC machining of steel creates more smooth parts than Titanium. However, various surface finishing approaches can be applied to enhance the surface quality and control the roughness.
| Steel CNC machining | Titanium CNC machining |
|
· Passivation · Powder coating · Carburizing · Bead blasting · Grinding · Nickel plating |
· Polishing · Plasma Electrolytic Oxidation · Plasma Nitriding · Anodizing |
Learn more:
What Is Passivation of Stainless Steel: A Comprehensive Guide
How To Polish Titanium: Ultimate Guide to Titanium Finishing
Comparison of Advantages
| Steel CNC machining | Titanium CNC machining |
|
· Low-cot manufacturing · Parts with high mechanical strength · High machinability · Complex shapes · Dimensional accuracy · Predictable reaction · Sustainability |
· Biocompatible · Superior corrosion resistance · High strength-to-weight ratio · Complicated shapes · Precision · Ability to Withstand Extreme Temperatures · Non-toxic · Aesthetic appeal |
Comparison of Disadvantages
| Steel CNC machining | Titanium CNC machining |
|
· Buckling · Heat sensitivity · High maintenance · Aesthetic appearance · More risk of corrosion |
· High cost · Deformation & possibility of cracking · Build up the edge · Complicated processing · Possibility of wear on tools |
Conclusion
Steel and Titanium are two common CNC machining materials that apply to many industries. These two materials come in a wide variety of alloys with impressive properties. Almost every CNC machining operation can be employed on these alloys using suitable tools and machining parameters. Selection of the ideal steel and titanium alloy requires a thorough understanding of their properties, machining conditions, requirements for intended use, and many more attributes.
ProleanTech provides CNC machining services for 50+ material options, including Titanium and steel. Our engineers closely analyze the requirements and precision feasibility to create the parts for an extensive range of applications. We have an experienced team of engineers and cutting-edge CNC technology to convert your design into reality.
FAQ’s
Is titanium stronger than steel?
Titanium has a higher strength-to-weight ratio compared to steel, making it stronger on a per-unit basis. However, steel has a higher overall strength, so it can still be the preferred choice for applications that require high load-bearing capacity and resistance to deformation.
How does the weight of titanium compare to that of steel?
Titanium is approximately 60% lighter than steel, making it an ideal choice for applications where weight reduction is critical, such as aerospace, automotive, and medical industries.
How does machining titanium compare to machining stainless steel?
Machining titanium is generally more difficult than machining stainless steel due to its lower thermal conductivity, higher chemical reactivity, and work-hardening tendency. Titanium typically requires slower cutting speeds, lower feed rates, and specialized tooling to prevent excessive tool wear and ensure precision.
Which material is easy to process with CNC machining, Titanium or steel?
Steel alloys have more machinability than titanium alloys. However, it can be processed easily with the correct machining tools and CNC parameters.
What are the advantages of Steel CNC machining?
Steel CNC machining offers complex shapes, dimensional accuracy, sustainability, cost-effectiveness, quick lead time, and many more benefits.
What types of steel are commonly used for CNC machining?
Common types of steel used for CNC machining include low carbon steel, tool steel, and stainless steel (such as 304 and 316). Each type has its own advantages and applications, depending on factors like strength, corrosion resistance, and machinability.
Why is Titanium difficult for CNC machining?
Titanium is difficult for precise CNC machining because of its characteristics, including its hardness, limited heat conductivity, and high mechanical strength. It necessitates taking into account several operational factors.
What are the advantages of Titanium CNC machining?
Titanium CNC machining offers parts with superior corrosion resistance, complicated shapes, precision, aesthetic appeal, and many more advantages.
Which material is ideal for my CNC machining project?
Selection between steel and Titanium for your CNC machining projects depends on the specifications, requires features, precision, intended use, cost, and many other factors.
Bibliography
- Hayes, D. K. (1956). Melting Point Determination Of Hafnium, Zirconium, and Titanium. Springer Link.
- (2015). Tool Steel | The Four Types of Steel. from https://www.metalsupermarkets.com/.
- (2014). Troublesome Titanium – Tips on machining this tough material. SANDVIK Coromant, from https://www.sandvik.coromant.com/.
- (n.d.). Whitney Suggested Cutting Speeds. WHITNEY TOOLS, from https://www.suncoasttools.com/.
This article has provided a great comparison between the two materials for me. How does ProLean ensure the optimal selection of material for specific project needs?”
ProLean’s expertise in CNC machining ensures the optimal selection of materials like titanium and steel based on project-specific requirements. We consider factors such as strength-to-weight ratio, machinability, and intended application to guide material choice. Our approach combines technical knowledge with a deep understanding of each material’s properties, ensuring clients receive the most suitable and efficient solution for their CNC machining needs