Surface treatment of stainless steel pipes

Stainless steel pipes are widely used in the fields of construction, chemical industry, food, and medical treatment due to their excellent corrosion resistance, high strength, and aesthetics. Different use environments have different requirements for surface finish, corrosion resistance, and decorativeness, so appropriate surface treatment processes are required. The following are common surface treatment methods for stainless steel pipes and their characteristics:

1. Mechanical surface treatment

(1) Polishing

Process: Use mechanical or electrolytic polishing to remove surface scratches and improve finish.

Effect: Mirror, satin, brushed, etc.

Application: Decorative pipes, medical equipment, and food equipment.

(2) Sandblasting

Process: Use high-speed sand particles to impact the surface to form a uniform roughness.

Effect: Matt texture and enhanced coating adhesion.

Application: Architectural decoration, chemical equipment.

(3) Grinding

Process: Grind with a grinding wheel or abrasive belt to eliminate welds and burrs.

Effect: Smooth and flat, suitable for high-precision pipes.

Application: Mechanical structural parts, precision instruments.

2. Chemical surface treatment

(1) Pickling

Process: Use a mixture of nitric acid and hydrofluoric acid to remove oxide scale and weld spots.

Effect: Silver-white matte surface, improved corrosion resistance.

Application: Welded pipes, industrial pipelines.

(2) Passivation

Process: Use nitric acid or citric acid to remove free iron and form a chromium oxide protective film.

Effect: Enhance corrosion resistance and extend service life.

Application: Pipes for food, medicine, and marine environments.

(3) Electropolishing

Process: Apply electricity to dissolve the metal ions on the surface to obtain an ultra-smooth surface.

Effect: Mirror-level finish, reduced bacterial adhesion.

Application: Semiconductor, biopharmaceutical pipelines.

3. Coating and plating treatment
(1) PVD coating (physical vapor deposition)
Process: Titanium, chromium and other metal films are plated in a vacuum environment.

Effect: Gold, black and other colored surfaces, wear-resistant and corrosion-resistant.

Application: high-end decoration, bathroom hardware.

(2) Spray coating
Process: Spray epoxy resin, fluorocarbon paint, etc.

Effect: Anti-corrosion, enhanced weather resistance, customizable colors.

Application: Building curtain walls, outdoor facilities.

4. Special treatment process
(1) Laser etching
Process: Laser engraving text, patterns or anti-counterfeiting marks.

Effect: Permanent identification without damaging the substrate.

Application: Industrial signs, high-end decoration.

(2) Coloring
Process: Generate colored oxide films (such as titanium and rose gold) by chemical or electrolytic methods.

Effect: Beautiful and corrosion-resistant.

Application: architectural decoration, artwork.

5. Surface treatment selection recommendations
Application scenarios Recommended treatment processes
Food/medical Electrolytic polishing + passivation
Chemical/marine Pickling + sandblasting + passivation
Architectural decoration PVD coating/spraying/brushing
High-precision machinery Precision grinding + polishing
Summary
The surface treatment of stainless steel pipes directly affects their corrosion resistance, aesthetics and service life. According to the use environment (such as corrosiveness, cleanliness requirements) and functional requirements (such as decoration, wear resistance), choosing the right process combination can maximize the performance advantages of stainless steel pipes.