I. Precise Matching Based on Usage Scenarios
Different operating conditions have significantly different core requirements, allowing for direct matching of solutions:
1. Ordinary Indoor Dry Environment: Phosphating + Rust-Inhibiting Oil Application – Low cost, meets short-term rust prevention and machining lubrication needs.
2. Outdoor/Damp Environment: Hot-Dip Galvanizing – Zinc layer thickness ≥85μm, salt spray life exceeding 500 hours, long-term corrosion resistance.
3. Highly Corrosive/High-Cleanliness Scenarios: Passivation Treatment – Suitable for stainless steel pipes, forming a dense protective film, resistant to chloride ion corrosion.
4. Food/Pharmaceutical/High-Purity Fluid Scenarios: Electrolytic Polishing – Surface roughness Ra≤0.1μm, residue-free and easy to clean, meeting sanitary standards.
5. Long-Distance Buried Pipelines: 3PE/TPEP Anti-Corrosion Coating – Strong coating adhesion, service life up to 50 years or more.
II. Avoiding Pipe Material Issues
Different materials have different characteristics, and choosing the wrong process can directly damage pipe performance:
1. Carbon steel pipes: Galvanizing and phosphating are preferred due to their higher cost-effectiveness, eliminating the need for expensive passivation.
2. Stainless steel pipes: Acid pickling and passivation followed by electrolytic polishing are preferred to avoid damaging the corrosion-resistant structure of stainless steel.
3. Alloy pipes: Hot-dip galvanizing at temperatures above 450℃ is prohibited to prevent the precipitation of alloying elements that could negatively impact mechanical properties. An epoxy zinc-rich primer + topcoat coating is recommended.
III. Considering Subsequent Processing Adaptability
If the pipes will undergo welding or cutting processes, acid pickling and shot blasting are preferred pretreatments to thoroughly remove surface oxide scale. This prevents oxide scale from causing weld porosity and accelerating tool wear by 3-5 times, ensuring processing accuracy and finished product quality.
