Product Description

Custom 304 Stainless Steel Tubing with Domed End Sealing, Diameter Changes, and Bending is a comprehensive fabrication service designed to create durable, one-piece tubular components with multiple integrated features. This process transforms straight lengths of 304 stainless steel tubing into complex parts by permanently sealing one end with a smooth, hemispherical dome (圆头), creating precise diameter transitions (变径) along the length, and forming accurate bends to achieve specific 3D geometries. The seamless integration of these operations results in robust, leak-resistant, and structurally sound parts ideal for fluid handling, structural frameworks, and specialized mechanical applications where hygiene, strength, and custom form are essential.

Product Processing

1. Material Selection & Cut-off: Annealed 304 stainless steel tubing of specified OD and wall thickness is selected, inspected, and cut to the required blank length.

2. End Doming/Sealing (圆头 forming): One end of the tube is sealed by a cold forming process:

   • Spinning or Swaging: The tube end is rotated and pressed against a forming die to create a smooth, hemispherical dome. This is a cold-working process that work-hardens the end, creating a strong, integral seal without welding.

3. Diameter Changing (变径 - Swaging/Reduction): Using rotary swaging machines, specific sections of the tube are radially compressed to create a reduced outer diameter. This can be a single-step reduction or a tapered transition. This step may be performed before or after doming, depending on the sequence that best maintains tolerances.

4. CNC Precision Bending: The tube, now with a sealed end and diameter changes, is loaded into a CNC tube bender. A mandrel is often inserted to prevent collapse or wrinkling, especially in the reduced diameter sections and through the bend radius. The machine executes programmed bends to achieve the desired angles and planes.

5. Heat Treatment (Stress Relief): After the cold working processes (doming, swaging, bending), the part undergoes a stress relief annealing treatment. This is critical for 304 stainless steel to relieve internal stresses, restore corrosion resistance in the worked areas, and prevent stress corrosion cracking.

6. Surface Finishing & Cleaning: The entire part is cleaned, and the surface finish is applied. This can include mechanical polishing (particularly of the domed end), electropolishing for a smooth, cleanable finish, or passivation to enhance corrosion resistance.

7. Final Inspection & Testing: Each part undergoes dimensional verification using CMMs or fixtures to check bend angles, reduced diameter dimensions, and dome geometry. The sealed domed end can be pressure tested or helium leak tested upon request.

Product Applications

• Food, Beverage & Pharmaceutical Processing: Custom dip tubes, vent tubes, or support legs for tanks and vessels where a smooth, sealed end prevents contamination, and bends navigate equipment layouts.

• Architectural & Furniture: Structural or decorative elements like railing posts, furniture legs, or display stands featuring a clean, domed foot, tapered sections, and artistic bends.

• Fluid & Pneumatic Systems: Custom manifolds, hydraulic lines, or gauge guards where a sealed end is needed, diameter changes accommodate different fitting sizes, and bends route around obstacles.

• Medical & Laboratory Equipment: Supports, frames, or handles for devices requiring a hygienic, sealed end, specific grip diameters, and ergonomic bends.

• Automotive & Marine: Fuel or fluid lines, push/pull rods, or custom exhaust components with formed ends and bends.

Product Technical Parameters (Detailed Table)