An Engineer's Guide To Titanium

For engineers and designers, titanium offers a compelling alternative to materials such as steel, brass and engineering plastics. Its combination of high strength-to-weight ratio and corrosion resistance makes it a commonly specified material in demanding applications. In addition to its technical properties, it’s also widely valued for its premium associations and distinctive aesthetics.

Like other materials, such as stainless steel, titanium is available in different grades, and it can be difficult to ascertain at a glance which grade is most suitable for a given application. Understanding the differences between titanium grades is essential when selecting materials for engineering and fastener applications.

This practical, engineer-led guide explains the most common titanium grades, which applications each is best suited to, and provides a grade comparison table.

Contents

• Why Use Titanium Screws?
• What Are the Downsides of Using Titanium Components?
• Titanium Grades Explained
• What Are the Different Grades of Titanium?
• Titanium Grade Comparison
• Grade 2 Vs Grade 5 Titanium
• Titanium Vs Steel Fasteners
• Which Titanium Grade Should I Use?
• Wrapping up Titanium Grades
• FAQs

Why Use Titanium Screws?

Before discussing the pros and cons of different grades of titanium, it’s best to lay out a broad overview of why engineers and designers choose to use it.

The primary strength of titanium is just that: its strength, particularly regarding its relative weight. Titanium can offer comparable strength to many steels while being significantly lighter, making it valuable in weight-critical applications such as aerospace, motorsport and high-performance engineering, where its high strength-to-weight ratio makes it an ideal material.

Titanium is also highly resistant to corrosion. It naturally forms a protective and stable oxide layer on the surface of the metal. This helps make titanium highly resistant to rust and degradation from environmental factors, like marine engineering projects where saltwater is present and exposure to aggressive chemicals. 

In addition, titanium performs well at elevated temperatures, retaining structural stability where other materials may degrade or deform. Many titanium alloys respond very well to precipitation hardening, which imbues them with much higher strength and durability, as well as resistance to creep. Creep refers to the tendency of a material to deform under sustained load. Certain titanium alloys are specifically designed for long-term use in high-temperature environments.

Finally, titanium is biocompatible, making it an ideal material to use for prosthetics, implants and medical applications where it is vital that the human body doesn’t reject or react to the materials used.

In fastener applications, these advantages can translate into lighter assemblies, improved corrosion performance and reliable clamping in demanding environments.

What Are the Downsides of Using Titanium Components?

The primary drawback to using titanium is its cost. Due to how complex it is to produce and the different procedures used to strengthen the alloys of titanium, it can be considerably more expensive to utilise in an assembly or application than stainless steel screws, for example.

It’s also less widely available than steel as it requires more specialised mining and manufacturing, making it more challenging to source. Impurities introduced during these processes can be extremely difficult to remove, meaning it has to be carefully managed at every stage of the process.

It’s also more difficult as a material to work with than steel. Due to its high tensile strength and heat resistance, titanium is much harder to machine, cut and form than steel or other metals.

For titanium fasteners, these factors typically show up as higher unit cost, tighter installation requirements and longer machining times for custom parts. In practice, titanium is often specified only when its performance benefits outweigh higher material cost and manufacturing complexity.

Titanium Grades Explained

Titanium grades are used to denote how pure the titanium used in a product is, as well as what materials it has been alloyed with in order to enhance it or make it more appropriate for a specific application.

There are more than 30 different grades of titanium, though many of these are extremely rare and have highly specific properties and applications. The most commonly used grades of titanium are Grades 1 to 9, and even within this grouping, there are some that are much more common than others.

Grades 1 to 4 are known as Commercially Pure (CP) titanium. These grades contain minimal alloying elements, with oxygen being the primary variable. As oxygen content increases, strength rises while ductility decreases:

Grades 5 and above are titanium alloys, engineered to deliver enhanced strength, fatigue resistance or high-temperature performance. It’s also commonly assumed that, as you progress through the grades of titanium, they increase in strength, which is not the case.

For components and precision fasteners made from titanium, these differences in grade can significantly affect strength, thread durability, corrosion resistance and suitability for specific environments.

Now that it’s clear what a grade of titanium is, it’s time to go over in detail what the properties of Grades 1-9 titanium are and what they’re used for. 

What Are the Different Grades of Titanium?

The following sections outline the most commonly used titanium grades, focusing on their defining characteristics and typical engineering applications.

The figures below are typical values based on commonly published material standards. Actual properties may vary depending on product form, processing and heat treatment.

Grade 1 Titanium.

• Ultimate tensile strength: ~240–345 Megapascal (MPa)

• Yield strength: ~170–240 MPa

• Elongation at break: ~24–30%

• Density: ~4.51 g/cm³

• Typical operating temperature: Up to ~300°C

Grade 1 is the purest commercially available titanium grade. It offers excellent ductility and very high corrosion resistance, but relatively low mechanical strength.

Its formability makes it well-suited to cold working processes, including bending and drawing. Grade 1 titanium is commonly used in architectural features, marine environments and chemical equipment where corrosion resistance is the primary requirement. It is also used for formed components where strength demands are modest.

Fastener considerations: Rare in threaded fasteners on cost/performance grounds; where it does appear, it’s typically in cold‑formed titanium hardware (e.g., formed parts/rivets/washers) when maximum ductility and cold formability are required and titanium is already justified by environment or mass constraints.

Grade 2 Titanium.

• Ultimate tensile strength: ~345–450 MPa

• Yield strength: ~275–345 MPa

• Elongation at break: ~20–25%

• Density: ~4.51 g/cm³

• Typical operating temperature: Up to ~400°C

Grade 2 is the most widely used commercially pure titanium grade, offering a balanced combination of strength, formability and corrosion resistance.

Compared to Grade 1, it provides improved mechanical strength while retaining excellent resistance to corrosive environments. Grade 2 titanium is frequently specified for pressure vessels, piping systems, heat exchangers and tanks used in chemical processing and desalination.

Fastener considerations: Chosen for corrosion‑critical fastening in seawater/chloride service and process plant environments where higher strength is needed, without compromising on corrosion resistance.

Grade 3 Titanium.

• Ultimate tensile strength: ~450–550 MPa

• Yield strength: ~380–450 MPa

• Elongation at break: ~15–20%

• Density: ~4.51 g/cm³

• Typical operating temperature: Up to ~400°C

Grade 3 titanium offers higher strength than Grades 1 and 2, with a corresponding reduction in formability.

This makes it suitable for applications where increased mechanical performance is required without moving to alloyed titanium. Typical uses include aerospace structures, industrial components and piping systems subjected to higher loads.

Fastener considerations: Uncommon in fastener supply, it’s mainly a niche option if you need a higher-strength, commercially pure titanium grade than Grade 2 (without alloying), but many fastener designs jump to Grade 5 for higher clamp loads and easier sourcing.

Grade 4 Titanium.

• Ultimate tensile strength: ~550–680 MPa

• Yield strength: ~480–550 MPa

• Elongation at break: ~12–15%

• Density: ~4.51 g/cm³

• Typical operating temperature: Up to ~400°C

Grade 4 is the strongest of the commercially pure titanium grades and the least formable.

Its combination of high strength, corrosion resistance and biocompatibility makes it a common choice for medical and surgical applications, including implants. It is also used in industrial environments where higher strength is required, but alloyed grades are not necessary.

Fastener considerations: Most relevant where you want commercially pure titanium at the highest strength, such as dental/medical screw and implant applications, where small diameters benefit from the extra strength margin.

Grade 5 Titanium (Ti-6Al-4V).

• Ultimate tensile strength: ~900–1,000 MPa

• Yield strength: ~830–900 MPa

• Elongation at break: ~10–15%

• Density: ~4.43 g/cm³

• Typical operating temperature: Up to ~400–450°C

Grade 5 is the most commonly used titanium alloy and is often referred to as Ti-6Al (aluminium)-4V(vanadium), based on its aluminium and vanadium content.

This grade offers an excellent balance of strength, fatigue resistance and thermal stability, along with a high strength-to-weight ratio. While its corrosion resistance is slightly lower than that of pure titanium grades, it remains suitable for most environments. Grade 5 is widely used in aerospace, motorsport, medical devices and high-performance fasteners. Because of its frequent use in aerospace applications, it’s often referred to as aerospace-grade titanium.

Fastener considerations: The workhorse for high‑strength, weight‑critical bolts and screws (widely used across aerospace/structural applications), it supports high preload for its weight, but installation typically needs controlled torque practices and anti‑seize to reduce galling risk.

Grade 6 Titanium (Ti-5Al-2.5Sn).

• Ultimate tensile strength: ~850–1,000 MPa

• Yield strength: ~750–900 MPa

• Elongation at break: ~10–15%

• Density: ~4.48 g/cm³

• Typical operating temperature: Up to ~480°C

Grade 6 titanium is alloyed with aluminium and tin, providing good strength retention at elevated temperatures and favourable weldability.

It is primarily used in aerospace applications where components are exposed to sustained heat. Grade 6 is commonly specified for jet engine components and other high-temperature structural parts.

Fastener considerations: Selected when fasteners must retain strength under sustained heat (up to ~480 °C), making it a candidate for hot‑zone aerospace joints where preload retention at temperature matters most.

Grade 7 Titanium (Ti-0.15Pd).

• Ultimate tensile strength: ~345–450 MPa

• Yield strength: ~275–345 MPa

• Elongation at break: ~20–25%

• Density: ~4.51 g/cm³

• Typical operating temperature: Up to ~400°C

Grade 7 is similar in mechanical performance to Grade 2 but includes a small addition of palladium to significantly improve corrosion resistance.

This makes it particularly suitable for aggressive environments, including exposure to chlorides and low-pH acids. Grade 7 titanium is commonly used in chemical processing equipment and desalination systems.

Fastener considerations: Preferable to Grade 2 when the joint geometry creates conditions where crevices and corrosion can take place, such as under washers and within countersinks. Minor palladium additions are commonly and specifically used to reduce that susceptibility.

Grade 8 Titanium (Ti-8Al-1Mo-1V).

• Ultimate tensile strength: ~900–1,100 MPa

• Yield strength: ~830–1,000 MPa

• Elongation at break: ~8–12%

• Density: ~4.54 g/cm³

• Typical operating temperature: Up to ~480°C

Grade 8, also known as 8-1-1 titanium, is alloyed to provide high strength and improved resistance to creep at elevated temperatures.

It is typically used in aerospace applications where components are subjected to sustained loads and thermal stress, making it suitable for structural parts requiring long-term stability.

Fastener considerations: A specialist choice where creep and stress‑relaxation at elevated temperature can reduce clamp load over time.  Ti‑8‑1‑1 is valued for creep resistance up to ~450 °C but is primarily an engine‑environment alloy, not a generally used fastener grade.

Grade 9 Titanium (Ti-3Al-2.5V).

• Ultimate tensile strength: ~620–750 MPa

• Yield strength: ~480–620 MPa

• Elongation at break: ~15–20%

• Density: ~4.48 g/cm³

• Typical operating temperature: Up to ~400°C

Grade 9 offers a balance between commercially pure titanium and higher-strength alloy grades. It provides improved strength over pure grades while remaining more formable and easier to weld than Grade 5.

This combination makes Grade 9 popular in applications such as bicycle frames, sporting equipment and lightweight structural components, where both strength and manufacturability are important.

Fastener considerations: Useful when you need a better balance of strength and cold workability than Grade 5, for example rolled threads or rivets. 

Titanium Grade Comparison

The table below provides a relative overview of the most commonly used titanium grades. Rather than presenting only absolute material properties, each characteristic is also scored on a numeric scale from 1 to 10, where 1 represents the lowest relative performance and 10 the highest within this specific group of titanium grades. For relative cost and availability, higher scores indicate greater availability and lower relative material cost within the titanium grades shown.

The scores are intended to highlight how the grades compare to one another, not how titanium compares to other materials, nor to define absolute limits or guaranteed performance.

This scoring system has been used to make trade-offs and design considerations easier to identify at a glance. The values are based on typical, widely recognised behaviour of each grade in engineering use, taking into account factors such as alloy composition, manufacturing characteristics and common application data.

 

Grade 2 Vs Grade 5 Titanium

Accu offers a range of Grade 5 titanium screws and fasteners, whereas many other manufacturers use Grade 2 titanium.

Grade 5 is often selected for fasteners because of its very high tensile strength, hardness, and corrosion resistance. While it’s outclassed in terms of its corrosion resistance by Grade 2 titanium, Grade 5 represents an ideal material for high-performance fasteners due to its low formability. While it makes the process of production more challenging, once formed it ensures that components will have a higher degree of durability and will be more resistant to stress.

Because of its relative abundance compared to other grades of titanium, like Grade 2, it also helps to keep the cost down and the availability high. While its formability isn’t a primary concern for engineers and designers looking to make use of titanium components in their assemblies, it is an important consideration for manufacturing and another factor that helps to reduce component cost.

Titanium Vs Steel Fasteners

Titanium Vs Stainless Steel Fasteners

There are many more grades, types and finishes of stainless steel available than there are grades of titanium. However, rather than directly comparing each grade of both materials, we can deal with them in broad terms.

So, why pick stainless steel fasteners over titanium fasteners? There are many compelling reasons for using stainless steel fasteners:

• Cost: Stainless steel fasteners are cheaper than titanium and, depending on the grades used and quantity, this may add up to a considerable cost saving across larger applications.

• Ease of machining: Stainless steel is considerably easier to machine than titanium, which can be a valuable time and money-saving property if components need to be customised.

• Balance of properties: While not able to boast the same corrosion resistance as titanium, stainless steel still has more than enough corrosion resistance, creep resistance and thermal performance for most applications outside of specialist use cases.

• Strength: Stainless steel alloys, particularly those that have undergone precipitation hardening, can attain a degree of tensile strength that outperforms that of titanium. Stainless steel is also less vulnerable to abrasion and scratching. As a material, it’s also more rigid and roughly 50% less bendable than titanium.

• Widely available: Stainless steel is far more readily available than titanium, and so components made from it are much less complex and expensive to source.

Titanium Vs High-Tensile Steel Fasteners

Another alternative to titanium components are high-tensile steel fasteners. As mentioned above, titanium is substantially lighter than steel, typically around 45%. However, if weight reduction isn't a primary design concern and strength is the most important feature driving material selection, then high-tensile steel is a viable option. 

So, why pick high-tensile steel fasteners over titanium fasteners? There are several compelling reasons for using high-tensile steel fasteners:

• Superior strength: High-tensile steel grades, particularly 12.9 and above, deliver tensile strengths exceeding 1,200 MPa, which outperforms Grade 5 titanium. This makes high-tensile steel the choice for applications where maximum clamping force in minimal space is the primary design requirement.
• Cost: High-tensile steel fasteners are significantly cheaper than titanium. For large assemblies or high-volume production, the cost difference can be substantial, particularly when corrosion resistance is not a critical factor.
• Rigidity and stiffness: Steel is approximately 2.5 times stiffer than titanium (measured by Young's modulus). In applications where deflection under load must be minimised or where precise preload retention matters, this additional rigidity can be advantageous.
• Ease of sourcing: High-tensile steel fasteners are widely available off-the-shelf in a broad range of sizes, thread pitches and head styles. Lead times are shorter and supply chains are well-established compared to titanium.
• Better wear resistance: High-tensile steel, especially when surface-treated or hardened, is more resistant to thread wear, galling and surface damage than titanium. This makes it preferable in high-cycle or frequently serviced assemblies where threads may be repeatedly loaded and unloaded.
• Magnetic properties: Unlike titanium, steel is ferromagnetic, which can be useful in applications requiring magnetic fastening, detection or alignment systems.

Critical limitation: High-tensile steel offers minimal corrosion resistance unless treated, typically through zinc plating or applying a black oxide coating. In marine, chemical or high-humidity environments, it will corrode rapidly. Where both high strength and corrosion resistance are required, Grade 5 titanium or precipitation-hardened stainless steel (like A4 - Marine Grade) is typically a more appropriate choice.

Which Titanium Grade Should I Use?

Selecting the right titanium grade depends on what matters most in your application, whether that be strength, corrosion resistance, formability, or thermal performance. The table above provides a comparative overview, but the guidance below can help narrow your choice more quickly.

• For maximum corrosion resistance: Commercially pure grades such as Grade 1 and Grade 2 are often suitable, particularly in marine, chemical or desalination environments. Where exposure to aggressive media is a concern, Grade 7 is also commonly specified.

• For general-purpose engineering applications: Grade 2 titanium is widely used due to its balance of strength, corrosion resistance and formability, making it a practical choice when no single property dominates the design requirements.

• For high-strength, weight-critical engineering designs: Grade 5 is frequently selected for aerospace, motorsport and high-performance components, offering excellent strength and fatigue resistance at a relatively low weight.

• For elevated temperature applications: Titanium alloy grades such as Grade 6 and Grade 8 are typically used where components are exposed to sustained heat and mechanical stress, particularly in aerospace environments.

• For improved formability with higher strength than pure grades: Grade 9 provides a useful middle ground, combining better strength than commercially pure titanium with easier forming and welding than higher-strength alloys.

• For medical and biocompatible applications: Grade 4 and Grade 5 are commonly specified, depending on the required balance of strength, fatigue resistance and manufacturability.

Wrapping up Titanium Grades

Titanium, from an engineering perspective, has tremendous benefits for many different applications. While it comes at a higher cost than components made from materials like stainless steel, there are clear use cases which make titanium the superior choice

If you’re unsure whether titanium components are right for your project, then contact our team of engineers. They’re ready to give advice and insight to help you make the decision.

Related Articles:

• Stainless Steel: Types, Grades and Finishes.

• Why Engineers Choose Grade 5 Titanium Fasteners.

• Ultimate Screw Buying Guide: Types & Materials.

• Choosing the Right Precision Engineering Components.

FAQs:

Q: Which titanium grade is best for fasteners?

A: For most fastener applications, Grade 5 titanium (Ti 6Al-4V) is the most commonly specified choice. It offers a strong balance of mechanical strength, fatigue resistance and low weight, making it suitable for bolts, screws and studs used in aerospace, motorsport and high-performance mechanical assemblies.

Where corrosion resistance is prioritised over maximum strength, such as in marine or chemical environments, Grade 2 titanium is often used instead. While not as strong as Grade 5, it provides excellent resistance to environmental degradation and is easier to form.

If cost is a factor and titanium is not specifically required, marine-grade A4 stainless steel may be a suitable alternative option.

Q: Can titanium fasteners be used with stainless steel or aluminium components?

A: Yes, but galvanic corrosion must be considered. Titanium is relatively noble compared to aluminium and some stainless steels, meaning corrosion can occur in the less noble material when dissimilar metals are in electrical contact, particularly in wet or salty environments.

To mitigate this, engineers often use insulating washers or coatings, anti-seize compounds or compatible material pairings where possible. These measures help reduce the risk of long-term degradation in mixed-material assemblies.

Q: Do titanium fasteners require lubrication or anti-seize?

A: In many cases, yes. Titanium is prone to galling, especially when fasteners are threaded into other titanium components.

Applying a suitable anti-seize compound during installation helps to reduce friction during tightening, achieve more consistent preload and prevent thread seizure during assembly or disassembly.

This is particularly important in precision assemblies or applications requiring repeated maintenance.

Q: Is titanium always the best choice for lightweight assemblies?

A: Not necessarily. While titanium offers an excellent strength-to-weight ratio, it is not always the most efficient or cost-effective option.

For example:

• Aluminium may be preferable where loads are low and cost sensitivity is high.

• High-strength steel fasteners may provide greater clamping force and tensile strength.

• Engineering plastics may be sufficient in electrically insulating or non-structural applications.

Titanium is most effective where weight reduction, corrosion resistance and mechanical performance must be balanced, rather than optimised for a single factor.