Manufacturing Process of Stainless Steel Pipes
The manufacturing process of stainless steel pipes is unique due to their exceptional corrosion resistance and high surface finish requirements. They are primarily categorized into seamless steel pipes and welded steel pipes.
Below is the complete production process flow and key technical points:
Manufacturing Process for Stainless Steel Seamless Pipes
Primarily used for small-diameter, thick-walled, or high-pressure applications.
a.Hot extrusion/hot rolling process (for thick-walled tubes)
b.Cold Drawing/Cold Rolling Process (Applicable to Precision Thin-Wall Tubes.
| Technical Key Points | |
| Cold Deformation | Prevent cracking. |
| Intermediate Annealing | Conducted in a protective atmosphere furnace to eliminate work hardening and restore plasticity. |
| Surface Treatment | After cold drawing, polishing or sandblasting is required to achieve the desired surface finish. |
Manufacturing Process for Stainless Steel Welded Pipes
High production efficiency and low cost, suitable for thin-walled, large-diameter pipes.
Comparison of Welding Methods:
|
Craftsmanship |
Features |
Applicable Steel Grades/Thicknesses |
Surface quality |
|
TIG welding |
Inert gas shielding ensures pure welds and high quality. |
All austenitic steels, thin-walled tubes |
Alright, no processing required or simple processing. |
|
Plasma welding |
Highly concentrated energy, strong penetrating power, and rapid speed |
Thick-walled pipe |
Better, with a smaller heat-affected zone |
|
Laser welding |
Ultra-high speed, high precision, minimal thermal deformation |
Precision Tubing |
Excellent, virtually seamless |
|
High-frequency welding |
High efficiency, low cost |
Conventional austenitic steel, thicker walls |
Both internal and external surface scraping required; weld seam treatment |
Special Treatment and Finishing
|
Craftsmanship |
Purpose |
Application Scenarios |
|
Pickling and Passivation |
Remove scale to form a chromium-rich passivation film, fundamentally enhancing corrosion resistance. |
Essential processes for all stainless steel pipes |
|
Electropolishing (EP) |
Achieve an ultra-smooth surface, reduce adhesion, and enhance corrosion resistance. |
Food, pharmaceutical, and semiconductor industries |
|
Mechanical polishing |
Achieve varying levels of brightness |
Decorative tubing, furniture tubing |
|
Sandblasting |
Form a uniform matte surface (with a consistent "hairline" pattern) |
Architectural decoration, electronic products |
Rigorous Quality Inspection
a. Non-Destructive Testing (NDT)
| Eddy Current Testing (ET) | Rapid detection of surface and near-surface defects. |
| Ultrasonic Testing (UT) | Detection of internal defects, used for thick-walled pipes. |
| Radiographic Testing (RT) | Assessment of weld quality. |
b. Corrosion Resistance Testing: Intergranular corrosion test.
c. Dimensional and Surface Inspection:
Laser diameter gauge, online eddy current thickness gauge.
Surface roughness tester, visual inspection
Summary of Process Selection
|
Demand |
Preferred Process |
Reason |
|
High pressure, high temperature |
Hot-extruded/hot-rolled seamless pipe |
Seamless construction ensures uniform pressure distribution and exceptional reliability. |
|
Precision Thin-Walled |
Cold-drawn/Cold-rolled Seamless Tubes |
High dimensional accuracy, smooth surface finish |
|
Large-diameter, cost-effective |
Welded pipe |
High efficiency, low cost, large diameter, easy to manufacture |
|
High surface finish requirements |
Welded pipe + Electrolytic polishing |
Achieve an ultra-smooth mirror finish on the inner walls. |
We are able to provide high quality Stainless Steel Pipe according to customers' needs and look forward to your purchase.
