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Manufacturing Requirements for Miniature Tantalum Tubes for Aerospace Fuel Injection

In the fuel injection systems of aerospace engines, miniature Tantalum tubes play a crucial role in precisely delivering fuel to the combustion chamber. Their minimum inner diameter can reach 40 micrometers, with a wall thickness of only 4 micrometers. Their dimensional stability under extreme high temperature and pressure environments directly determines the engine's thrust and safety. To achieve such miniature size and adaptability to extreme environments, the manufacturing technology must meet "aerospace-grade" standards.

High-temperature strength is a core requirement for aerospace-grade Tantalum tubes, which relies on precise heat treatment processes. After forming, the tantalum tubes undergo vacuum annealing at 1200℃, with the holding time strictly controlled to 2 hours, ensuring uniform grain size of 5-10 micrometers, guaranteeing high-temperature strength while avoiding brittleness. Test data shows that Tantalum tubes treated with this process still maintain a tensile strength of 600 MPa at 1000℃, while Titanium alloy tubes only have a tensile strength of 300 MPa at the same temperature. Although nickel alloys can achieve a high-temperature strength of 1400 MPa, they cannot be processed into thin tubes with an inner diameter of 40 micrometers, and their density is 1.5 times that of tantalum, which is detrimental to weight reduction. Precision rolling is a key process for achieving the miniaturized dimensions of aerospace tantalum tubes. Utilizing three-roll planetary rolling technology, Tantalum tube blanks are progressively rolled from an initial diameter of 1.5 mm to a fine tube with an inner diameter of 40 micrometers. During the rolling process, the roll speed and feed rate are controlled in real time by computer, with speed fluctuations not exceeding 5 r/min and feed rate accuracy reaching 0.001 mm. This process ensures that the wall thickness uniformity error of the tantalum tube is less than ±0.3 micrometers, far superior to the traditional two-roll rolling process. In comparison, when stainless steel tubes are rolled using three-roll rolling, due to insufficient ductility, the minimum inner diameter can only reach 100 micrometers; titanium alloy tubes are prone to rolling cracks, resulting in a scrap rate of over 40%.

High-temperature oxidation resistance treatment is an essential process for aerospace Tantalum tubes. Through plasma spraying technology, a 5-micrometer-thick alumina coating is applied to the surface of the tantalum tube. The coating's bonding strength with the substrate exceeds 50 MPa, and it can operate continuously for 1000 hours at 1200℃ without peeling off. This coating effectively prevents tantalum from oxidizing at high temperatures, while uncoated tantalum tubes rapidly oxidize and fail above 800°C. In contrast, the oxide film on titanium alloy tubes cracks above 600°C, and stainless steel tubes exhibit intergranular corrosion at high temperatures, neither of which meets the long-term operational requirements of aerospace engines.

Strict dimensional and performance screening is the final hurdle before aerospace tantalum tubes leave the factory. The inner diameter accuracy is measured using a pneumatic gauge, with an error controlled within ±0.5 micrometers; after 100,000 cycles at 800°C, the dimensional change rate is less than 0.1% through high-temperature fatigue testing. Each aerospace-grade tantalum tube is individually numbered, allowing for full traceability of production data, with a defect rate controlled below 5%. This extreme process control makes miniature tantalum tubes a crucial guarantee for breakthroughs in high thrust and lightweight design for aerospace engines.

AlloyHit specializes in producing Tantalum Tubes, Tantalum Capillary in various specifications.