Polished Tantalum Welded Crucible

    In the ultra-high vacuum induction melting and strategic rare earth element (REE) extraction process of more than 1500 °C, the crucible is not only the carrying vessel, but also the key to determining the purity of the melt. Due to the extremely low utilization rate of raw materials, the procurement cost of the overall bar machined super-large pure tantalum crucible is extremely high.

    In 2026, we launched the Engineered Welded Tantalum Crucibles, which adopted 99.95% electronic grade high-purity tantalum plates, combined with fully automatic vacuum electron beam welding (EBW) and subsequent thermo-mechanical weld refinement technology (Post-Weld Grain Refinement), successfully controlled procurement costs while achieving high-temperature creep resistance and zero air leakage performance comparable to seamless crucibles.

I. Core Technology Advantages (Elite Engineering Advantages)

    Vacuum Electronic Beam Welding-Zero Defect: All of our welding tantalum crucibles are electron beam welded in an ultra-high vacuum cavity of 10-4Pa. Ultra-high energy density makes the butt edge instantly 100% fused without any welding, porosity, oxidation or slag inclusion. Each crucible has passed strict Helium Mass Spectrometer Leak Detection (Helium Mass Spectrometer Leak Detection) before leaving the factory, and the leakage rate is ≤ 10-10 Pa · m ³/s, ensuring that the vacuum is finished.

    Post-Weld Micro-structure Optimization: Aiming at the pain point of "weld is the dead spot" of welded parts, we carry out special local rolling and recrystallization annealing on the weld area after welding. This exclusive process completely breaks the Columnar Grains during welding and solidification, and converts them into fine and uniform Equiaxed Grains (Equiaxed Grains), so that the mechanical strength and tensile properties at the weld seam reach 95% of the base metal above.

    Super-sized manufacturing capacity and Cost-Effective Scale Optimization: Breaks through the size limit of large-diameter, ultra-thin-walled crucibles imposed by the integral bar hollowing machine. Through precise plate rolling arc forming and bottom welding, we can greatly save rare and precious metal raw materials (material loss up to 60%), and at the same time customize large-scale industrial smelting grade tantalum crucibles with a diameter of more than 500mm.

II. Basic Parameters and Technical Specifications (Technical Parameter Matrix)

III. Strict gas gap element control (Chemical Profile Weight%)

    In order to prevent the embrittlement of tantalum due to gas absorption at high temperature, we strictly limit the impurity content in the plate and welding from the source (in accordance with the ASTM B708 electronic grade low gap element standard):

    Ta (major element purity): ≥ 99. 95%

    O (oxygen): ≤ 0. 015% N (nitrogen): ≤ 0. 010% H (hydrogen): ≤ 0. 0015%

    C (carbon): ≤ 0. 010% Fe (iron): ≤ 0. 010% Nb (niobium impurity): ≤ 0. 050%

IV. Precision Welded Manufacturing

    Flow CNC blanking of high-precision plates and: ASTM B708 high-quality high-purity tantalum plates are selected, and the roundness tolerance of the cylinder body is guaranteed to be ≤ 0.5 mm through CNC blanking and precise arc rolling.

    Edge ultra-purification pickling: Before welding, the edge of the butt weld is subjected to harsh chemical oxidation removal film and ultrasonic de-greasing, and any trace impurities are strictly prohibited from entering the weld pool.

    High vacuum electron beam welding (EBW): One-sided welding and double-sided forming (Full Penetration) at one time under absolute vacuum without any shielding gas interference, ensuring absolute material purity.

    Thermo-mechanical modification and integral annealing of welds: The welds are hammered or rolled at high frequency, and then sent to a vacuum furnace for integral recrystallization annealing above 1200 °C to completely eliminate residual welding stresses.

V. Cross-border cutting-edge applications (High-Value Applications)

    Rare Earth Element Refining (Rare Earth Element Refining): Tantalum has extremely high resistance and corrosion resistance to molten rare earth metals such as lanthanum, cerium, neodymium, and praseodymium, and is the core of smelting ultra-high-purity special strategic rare earth alloys container.

    Vacuum coating and electron beam evaporation sources (PVD Coating Sources): In a high-power electron beam bombardment coating machine, it is used as a melting support for large-capacity metals (such as high-purity aluminum, copper, and silicon).

    Nuclear energy and high-temperature molten salt chemistry (Molten Salt Reactors): In nuclear reactors and thorium-based Molten Salt Reactors (TMSR) experiments, it is used as a chemical reaction reactor that can withstand the high-temperature corrosion of extreme fluoride salts and chlorinated salts.