Molybdenum Welded Tube

   Conventional nickel-based super-alloys, tantalum or niobium tubes are either softened by reaching a melting point or limited by being extremely expensive in ultra-high temperatures, high vacuum, or strong reductive protection (such as hydrogen) beyond 1100 °C to 1800 °C Industrial scale applications are limited.

    Our Engineered Welded Molybdenum Tubes & Pipes strictly use 100% high-quality high-purity Mo1 (purity ≥ 99. 95%) high-precision cold-rolled molybdenum plate as the base metal, combined with advanced fully automatic inert gas shielded tungsten arc welding (TIG/GTAW) or high vacuum electron beam welding (EBW) process. This series of products perfectly solves the processing pain points of the core components of large-diameter, ultra-thin-walled monocrystalline silicon and sapphire growth furnaces (such as molybdenum heat shields, feeding pipes, and heat-insulating liners), with the ultimate Creep Resistance comparable to seamless pipes Performance (Creep Resistance) and extremely high cost performance fully empower the global semiconductor and heat treatment supply chain.

I. Excellent core advantages (Elite Engineering Advantages)

    Ultra-Low Oxygen Weld Metallurgy: Molybdenum is a typical refractory metal with extremely high resistance to oxygen (O). If the oxygen content in the welding area exceeds the standard, it is very easy to precipitate microscopic oxides at the grain boundary, resulting in devastating cold brittle cracks in the weld. Through high-purity back-blown argon (purity ≥ 99. 999%) and a special fully isolated trailing protective cover, we implement zero-blind zone atmosphere blockade during the entire welding process to ensure that the content of gap elements (O, N, H) in the weld area is compressed to an extremely narrow window at the ppm level.

    Post-Weld Thermal mechanical Stress Relieving (Post-Weld Thermal mechanical Stress Relieving): In response to buyers' concerns about "grain coarsening and brittle fracture in the molybdenum weld zone", we implement full-system Stress Relief Annealing for pipes after welding (Stress Relief Annealing). By adjusting the recrystallization kinetics in a specific medium and high temperature range, not only the residual deformation stress is completely eliminated, but also the microstructure of the grain boundary in the weld and heat affected zone (HAZ) achieves a perfect plastic-toughness balance with the base metal.

    Geometric Freedom Breaking the Limits of Seamless Pipe Specifications & Cost Optimization: Seamless molybdenum pipes are subject to drawing and process, making it extremely difficult to manufacture large-diameter (outer diameter ≥ 100 mm) and ultra-thin-walled (wall thickness ≤ 2. 0mm) pipes. Through precision roll forming (Rolled & Welded), our welding process can easily customize various super-large diameter molybdenum slides, molybdenum sleeves and heat insulation cylinders, which greatly reduces the cutting loss of rare metal raw materials. Compared with seamless pipes, it can save customers 30%-50% of procurement costs.

II. Core Mechanical Properties and basic information parameters (Mechanical Properties & Technical Parameters)

    We carry out strict re-inspection on each batch of welded pipes before leaving the factory. At room temperature (20 °C), the physical and mechanical indicators of its welded deposited metal and substrate are excellent:

    Core grade (Material Grade): Mo1 (High Pure Molybdenum/Unalloyed Pure Molybdenum)

    Molybdenum Purity: ≥ 99.95% (no potential impurity volatilization pollution to semiconductor thermal field)

    Tensile Strength: ≥ 500 MPa-750 MPa (fine-tuned with wall thickness and work hardening rate)

    Yield Strength: ≥ 400 MPa

    Elongation: ≥ 5%-15% (after fine stress relief annealing, it presents excellent room temperature reprocessing and impact toughness)

    Operating Temperature (Max Operating Temperature): 1800 °C (in vacuum or perfectly inert gas)

    Melting Point: 2620 °C

III. Strict Technical Standards and chemical composition control (Technical Standards & Chemical Profile %)

    We implement stricter internal control on impurity elements that affect high-temperature creep life and weld density than international general norms, and fully benchmark ASTM B387 standards: Chemical Composition by Weight%:

    Mo (molybdenum purity): ≥ 99. 95%

    Fe (iron): ≤ 0.0030% Ni (nickel): ≤ 0.0020% Si (silicon): ≤ 0.0030%

    C (carbon): ≤ 0. 0050% O (oxygen): ≤ 0. 0030% (30 ppm) N (nitrogen) + H (hydrogen): ≤ 0. 0020%

IV. Product Specifications Range

    Implementation of Technical Standards: ASTM B387 (Industry General Requirements for Molybdenum and Molybdenum Alloy Rod and Bar Standard Specification for Molybdenum and Molybdenum Alloy Rod and Bar).

    Implementation of Technical Standards: ASTM B386 (Industry General Requirements for Molybdenum and Molybdenum Alloy Plate, Sheet, and Foil Standard Specification for Molybdenum and Molybdenum Alloy Plate, Sheet, and Foil).

    Outer Diameter range (Outer Diameter): φ 30 mm-φ 600 mm (from small feed pipes for high vacuum furnaces to super-large thermal field ring members)

    Wall Thickness: 1.0 mm-10.0 mm (excellent thin-wall control technology)

    Product Length (Length): The maximum Length of a single stick can reach 1000 mm-1500 mm, and supports precision end face numerical control flush and field drawing welding assembly on demand.

V. Lean Manufacturing Process and Surface Treatment

    Precision cutting and milling of cold-rolled molybdenum plates: high-quality Mo1 molybdenum plates that have been melted by vacuum self-consumption or electron beam for many times are selected, and are cold-rolled to the target wall thickness by high-precision, and V-shaped grooves are micro-machined on the butt edges by high-precision CNC milling machines to completely remove work-hardening burrs.

    Ultrasonic purification cleaning of the edge: The butt area undergoes extremely strict chemical degreasing and micro-pickling before welding, which completely removes the possible residual cold-rolled oil, fingerprint oil and oxide scale on the surface, and kills the source of welding Porosity from the physical level.

    Precision TIG/EB Welding: Place the formed tube blank in a high-precision fixture, and use high-current automatic TIG welding or vacuum cavity electron beam welding for longitudinal seam fusion.

    Surface Finish Options:

    Pickled/Pickled Finish: Shows a clean, uniform matte silver gray.

    Machined/Polished Finish: After cylindrical and mechanical grinding, the surface roughness can reach Ra ≤ 0.8 um, which is the feeding standard for semiconductor cavities with extreme particle pollution.

VI. Global Cutting-edge Applications (High-Value Market Applications)

    Semiconductor and Sapphire Long Single Crystal Furnace Thermal Field (Sapphire & Silicon Crystal Growth Furnaces): Used as high-temperature gas spray tubes, vacuum temperature measurement sleeves, and Thermal Shields (Thermal Shields) core support tubes inside single crystal drawing equipment, under white-hot loads close to 2000 °C, the material will not deform and pollute the silicon/Sapphire melt for a long time.

    High-end High-Vacuum Resistance Furnaces and vacuum heat treatment furnaces (High-Vacuum Resistance Furnaces): the high-temperature electrode insulation protective sleeve, molybdenum support frame and high-temperature gas circulation pipeline as the center of the vacuum chamber in the furnace.

    And Nuclear Thermoelectric Conversion (Aerospace & Advanced Nuclear Hardware): In the extreme high temperature airflow conduction pipeline of special space reactors (Space Nuclear Power) and forward missiles, it is used as a lightweight and ultra-high temperature resistant high-efficiency structural material.