Miniaturization makes advanced aerospace technology more accessible to smaller organizations that previously couldn’t afford the equipment. This accessibility allows more people to innovate and advances the industry. The development of Stellite alloys greatly enhanced internal combustion engine exhaust valve poppet valve and valve seat manufacturing. It significantly lengthened the interval between maintenance and re-grinding of the valve seats.
Increased Safety
Unlike other metal alloys, handling Stellite parts in a well-ventilated area poses no safety hazards. However, machining and welding can produce dust, fumes, and small particles that are respiratory irritants for some people. When these materials are inhaled, they can cause bronchitis and lung damage. They can also irritate the skin. Using laser surface alloying instead of welding for this process offers even more benefits. It produces a better bond with the base metal and creates a more uniform overlay.
Additionally, the process has a smaller heat-affected zone and lower thermal distortion. It is also more cost-effective and allows for a faster turnaround than the alternative. Lastly, adding elements to the coating without increasing the risk of corrosion or wear is possible.
Reduced Maintenance
The cobalt-based stellite alloys are characterized by hard carbides in their matrix and are highly resistant to corrosion, galling, abrasion, and cavitation erosion. They also retain their strength at high temperatures. The material most often used for hard-facing valve internals is a cobalt-based Stellite 6 alloy with chromium, tungsten, and carbon. This alloy is highly resistant to erosion and galling. Typical applications include saw teeth, hardfacing, and acid-resistant machine parts.
A specialized form of this material, called Talonite, is manufactured by hot-rolling and hardening a combination of specific alloys and then grinding them together to create a uniform abrasion-resistant matrix. It is highly durable and has excellent machinability. Poppet valve and valve seat production for internal combustion engines has significantly improved. It reduces erosion from hot gases and increases the interval between maintenance and resharpening of the seats.
Increased Performance
Aerospace engineers are continually seeking ways to improve the performance of aircraft. It may be achieved through structural optimization that reduces weight without sacrificing strength or using materials with exceptional wear resistance. Stellite is a series of cobalt alloys designed for corrosion and wear resistance. It often contains tungsten and molybdenum. It is a hard material with good machinability and can resist galling, cavitation erosion, and metal-to-metal sliding wear. The abrasion resistance of stellite allows it to be used for components in gas turbines and compressors. It also has good oxidation resistance and heat tolerance, making it suitable for high-temperature applications. It is important to note that satellites cannot be used in nuclear power plants as minute amounts of the alloy will change to Cobalt-60, a radioisotope with a half-life of five years, and releases harmful gamma radiation.
Reduced Costs
Stellite parts’ high hardness, machinability, and durability reduce production costs. In the aerospace industry, production directly from CAD data removes tooling restraints and allows designers to build aircraft and rocket engines with fewer components. It saves time and money and reduces potential failure modes requiring joint welding. Stellite coatings can resurface flanges, sectors, and heat shields to reduce vibration in machinery that generates electricity.
They are combined with various heat, wear, and corrosion solutions.
