NXF UNS S304/ 1.4301/SUS304/Z7CN18-09 Diameter 10-2000mm Thickness 0.8-5mm Stainless Steel Hollow Ball

1. Raw material preparation

Select 304/316 stainless steel solid round billets. Inspect the material composition and ensure there are no cracks or sand holes on the surface. Cut the billets to the desired length, remove the burrs and oxide scale from the ends, and perform pre-treatment for perforation.

2. Hot perforation forming

After the billets are heated at high temperature, they are sent to the perforation unit. Through oblique rolling perforation, hollow rough tubes are formed, obtaining the basic hollow round shape; the wall thickness deviation of the rough tubes is large and the surface is severely oxidized, and they are only semi-finished products.

3. Cold drawing / Cold rolling finishing (core process)

The rough tubes are acid-washed to remove the oxide scale, and lubricating coatings are applied. Through multiple passes of cold drawing or cold rolling, the outer diameter is gradually reduced and the wall thickness is controlled; repeated rolling ensures smooth inner and outer walls and meets the dimensional tolerance requirements, achieving the precision bright tube accuracy.

4. Solution annealing and bright annealing

After cold processing, the pipe materials have internal stress. They are placed in a vacuum bright annealing furnace for high-temperature heat treatment to eliminate work hardening and restore metal toughness; the entire process is isolated from air to prevent the pipe from blackening and maintain a mirror-like / wire-wrapped bright surface.

5. Precision straightening and cutting

The annealed pipe materials are corrected for bending by the straightening machine, then cut to the customer's specified length, with both ends having flat flanges and burrs removed to ensure the pipe ends are flat and without deformation.

6. Cleaning, flaw detection, and inspection

Ultrasonic flaw detection is used to check for internal cracks and uneven wall thickness in the pipe walls; water pressure / air pressure tests are conducted to verify the pressure-bearing capacity; degreasing and cleaning remove oil stains, and the outer diameter, wall thickness, and surface finish are inspected after drying.

7. Identification, packaging, and storage

Qualified pipe materials are printed with material, specification, furnace batch number labels, wrapped with protective films, classified and bundled, packaged for moisture protection, and then stored and shipped.