Production Considerations for Aerospace Titanium
Aerospace titanium fills a vital role in aircraft production around the world, and that role continues to grow every year. In fact, nearly 40% of the F-22 Raptor aircraft structure is composed of titanium!
The impressive mechanical properties of titanium aerospace castings – including superb corrosion resistance, strength-to-weight ratio, and fatigue strength – explain its widespread use in the industry. The process of manufacturing aerospace titanium components and systems, however, can be complicated and meticulous. Properties such as chemical composition, strength, and hardness must be carefully controlled and tested in order to meet stringent aerospace industry requirements. Let us take a closer look at these requirements to fully understand the applications for aerospace titanium and its possible alloys.
Ti-6Al-4V – The Standard for Aerospace Titanium
Ti-6Al-4V – or Grade 5 Titanium alloy is the most used form of aerospace titanium, and represents approximately 50% of the entire titanium usage for all applications worldwide. The designation itself partially reveals the chemical composition that must be achieved to qualify as Grade 5 titanium. Aluminum (Al) and vanadium (V) account for approximately 6% and 4% of the alloy’s chemical composition respectively, along with iron and oxygen each composing less than 0.30% each.
The mechanical properties of titanium receive equally intensive scrutiny in aerospace. Just as the chemical composition must meet specified values, tensile strength, yield strength, and elongation must meet specified standards. A variety of quality standards – AMS, MIL, and ASTM for American Industry – govern the chemical composition, mechanical properties, and other quality requirements.
Naturally, the mechanical properties of aerospace titanium vary when produced using different material conversion procesess; for example: cast vs. forged vs. fully machined from bar stock. For this reason, mechanical and other properties are segmented to offer guidance for different material conversion processes. For example, AMS 4991, AMS 4992, and/or occasionally ASTM B367 establish the requirements for Grade 5 aerospace titanium castings. Forged Grade 5 titanium, however, typically follows ASTM B381 requirements. Aircraft Materials Ltd has put together a good table of Ti-6Al-4V specifications.
For an example of common Grade 5 titanium properties, consider castings exposed to Hot Isostatic Pressing (HIP). With post-cast HIP, typical values of 135ksi tensile strength, 120ksi yield strength, and 9% elongation can be achieved. These values are impressive, and hence properly processed titanium castings can add tremendous value to the aerospace industry. But there is always room for improvement.
FS2S – A Superior Titanium Alloy
Grade 5 titanium’s current position as the prominent aerospace titanium alloy does not necessarily indicate that it is the superior option. The specifications previously referenced indicate minimum strength and process requirements. FS Precision has developed a superior titanium alloy with our advanced FS2S titanium alloy.
While adhering strictly to general industry specifications applicable to a given program – as well as those additional requirements sometimes required by our customers – FS Precision has developed an aerospace titanium investment casting alloy which measurably outperforms standard Grade 5 mechanical properties. Our near-net cast FS2S aerospace titanium improves upon Grade 5 by approximately 10% with tensile and yield strengths of 148ksi and 135ksi respectively.
Fatigue strength and ductility are also bolstered with an elongation value of 12%. Overall, these values make our cast titanium comparable to wrought and annealed alloys which are typically stronger than conventional cast alloys.
The chart below illustrates Yield Strength as a function of temperature for FS Precision’s FS2S alloy compared to conventional Grade 5 titanium. For more details, download the FS2S Spec sheet.
FS Precision Tech’s FS2S alloy exceeds all conventional titanium alloy specifications, and is available to support the reliability and longevity of the next generation of aviation structural components.
If you’d like to learn more about our production processes, watch this investment casting video. Or if you’d like to explore how we can assist you with your needs for aerospace titanium, please click on the button below and send us your project details. In most cases we can respond within 1-2 business days with an estimate of cost and lead time to assist you in your program development process.
FS Precision is different from all of the others in the industry, because we go out of our way early in your process to help you and your development team to create an optimized solution.
FS Precision is the emerging global leader for structural investment castings for fixed wing, rotary wing, space launch, and defense systems. Our AS9100D certified investment casting foundries are located in the USA and Taiwan. Our USA factories are ITAR and FFL registered, and our Taiwan facilities actively support the fulfillment of customer offset obligations to Taiwan.