Material selection, in any subsection of aerospace engineering, can determine if a flight is successful or if it is calamitously disastrous. These standards – AMS 6490 is one of them and to many people outside the industry, it is rather difficult to comprehend the significance of it.
What is AMS 6490?
AMS 6490 is an aerospace material specification for alloyed high strength steel. The vacuum melted 4340 type low alloy steel, is becoming increasingly used as a primary constituent for the structural components of aircraft. This steel specification has an exact chemistry, mechanical properties, and quality requirements that demand reliability in the most hostile environments.
As AMS 6490 represents material certification, it encompasses ‘am the rigor of engineering scrutiny’ which is the burden of every standard. The standard does not represent a mere set of figures and criteria for compliance annexes, it is the result of decades of refining steel, thorough experience, and metrological engineering.
Key Properties That Matter
The steel encompassed under this specification possesses a remarkable combination of properties which are:
• Tensile Strength Usually Obtained More Than 1860 Mpa (270 ksi)
• Ductility and toughness balance is good
• Ability to be toughened is remarkable
• Fatigue resistance is good
• To be hardened is strong
All these properties require stringent control of carbon, manganese, nickel, chromium, and molybdenum percentages with their associated heat treatment and vacuum melting processes. The melting procedure eliminates a host of inclusions and impurities which are destined to be the failure points during stress for some of the stronger HPCs.
Where You’ll Find AMS 6490 In Use
This specification is recognised across numerous industry verticals for different critical use cases.
Some of the most critical components of an Aircraft like the Landing gear must sustain and absorb an incredible amount of energy during landing while not contorting, getting deformed or bending. These conditions along with the extreme ductility steel absorb makes the bolstered landing gear steel perfect for these STEELS.
The structural parts of a cantilevered frame need enduring support of hundreds of kilograms. Steel AMS 6490 guarantees the sustainment of these powerplant zed components, being the core, with vibrational and thermal cycling induced torque, for thousands of flight hours.
The aircraft have an absolute requirement for critical support structural linkages that possess high bearing strengths but low mass – yet another battle which this specification excels in.
Challenges With Using High-Strength Steels
The problems presented with these materials are integrated to pose the greatest challenges. The challenge comes with processing because of the material’s value.
Heat Treatment is critical of all the operations. It is dangerously close to being feather-like brittle at the peak of strength and needing to be tempered. Balance proper quenching with providing the needed microstructure throughout parts. Obtaining tempered results is critical with no balance required at the standard.
Machining these steels requires the use of specialist cutting tools, along with knowledge in the field. Because the hardness must be dealt with, operations using standard mechanical methods post-heat treatment will not get sought-after results.
Hydrogen embrittlement is another equally concerning aspect. If one out of numerous, often overlooked, flaws must be treated carefully during processes, the protocols need to modify to avoid adding handles.
Why is High-Strength Steel Used in Aerospace?
High-strength aluminium and composite materials currently take the lead, but the reason steel and AMS 6490’s area of use remains relevant is due unmatched combinations of strength, impact resistance, and general physical assault.
New improvements being made to melting techniques in surface treatment and heat treatment increase the materials’ efficiency.
Both vacuum arc remelting and electroslag remelting increase material quality and enhance fatigue properties.
The specification continues to be relied upon due to its unparalleled performance, particularly in the aerospace sector, which has long relied on it for its unyielding performance.
Preferred industries serving the safety-sensitive sectors combine AMS 6490.
Although time can change a great many things, AMS 6490 will certainly outlast such advances in technology.