PFA lining has low surface hardness and poor resistance to particle abrasion. When the pipeline medium carries solid particles, crystalline salts or impurity sediments to flow and rub against the coating surface for a long time, the fluoroplastic layer will be gradually scraped and thinned. Local areas are worn through to form through holes, corrosive liquid directly contacts the metal base pipe and triggers substrate corrosion. Abrasion wear mostly occurs at high-flow flushing positions, presenting uniform thinning or strip-shaped worn grooves on the coating surface, which is a common service failure of PFA lined heating tubes in solid-containing medium systems.
1. Abrasion Material Removal Mechanism
The surface of PFA coating is soft and smooth under static conditions. Hard suspended particles in the fluid continuously slide, roll and impact the lining surface with medium flow. Micro-cutting and ploughing effects strip tiny fragments from the polymer surface layer by layer. With prolonged operation, the coating thickness decreases uniformly. Once the lining is worn through, the protective barrier completely fails. Different from impact damage which is instantaneous concentrated force destruction, abrasion wear belongs to cumulative material loss caused by continuous micro friction. Temperature increase will soften PFA material and further accelerate the abrasion loss rate.
2. Typical Positions Prone to Abrasion Wear
Pump inlet and outlet straight pipe sections with the highest flow velocity and strongest particle scouring;
Outer arc surface of elbows where fluid turns and particles concentrate to strike and rub;
Tee joints, sudden diameter change sections with turbulent flow and intensified wall friction;
Bottom of horizontal pipelines where solid impurities settle and slide to grind the coating;
Heating tube inlet directly facing incoming medium jet flushing.
3. Key Factors Accelerating Abrasion Damage
Large quantity of sand, rust slag, crystal particles and other hard impurities in circulating medium;
Excessively high flow rate leading to strong kinetic energy of particles and severe scraping effect;
Insufficient designed coating thickness with no wear allowance reserved;
High operating temperature softening PFA and reducing surface anti-scouring ability;
No front-end filtering facilities to intercept particulate impurities at the source.
4. Whole-Link Prevention and Control Technical Measures
① Install precision filtration and deslagging equipment at the system front end
Filter out solid particles fundamentally to eliminate the source of abrasion.
② Optimize pipeline structure to reduce turbulent flushing
Adopt large-radius elbows and streamlined pipe fittings to avoid directional concentrated particle impact.
③ Appropriately reduce medium flow speed within production permissible range
Lower pump frequency to weaken particle impact and friction intensity.
④ Carry out local thickened lining treatment on vulnerable wear parts
Increase coating thickness on elbows and inlets to reserve sufficient wear margin.
⑤ Adopt wear-resistant modified PFA raw materials for harsh working conditions
Add inorganic wear-resistant fillers to improve surface hardness and anti-abrasion performance.
5. Prevention Effect Comparison Table
表格
| Medium & Lining Scheme | Abrasion Wear Risk | Application Suggestion |
|---|---|---|
| Unfiltered particle medium + standard thin PFA lining | Fast local penetration and substrate corrosion | Add filtration and thicken vulnerable positions immediately |
| Front-end impurity interception + structural optimization + local thickening | Effectively extend lining service life | Particle-containing medium standard configuration |
| Filler modified wear-resistant PFA + regular thickness inspection | Minimal cumulative abrasion loss tendency | Long-term solid mixed fluid preferred option |
Conclusion
PFA coating abrasion wear failure is caused by long-term continuous micro-cutting and scraping of solid particles against the soft fluoroplastic lining, resulting in gradual thinning and perforation of the anti-corrosion layer. Core control means include intercepting abrasive impurities at the source, optimizing flow field to reduce concentrated scouring, reserving wear allowance by thickening key areas, and upgrading wear-resistant modified lining materials. Closed-loop management of medium purification, pipeline design and lining process can effectively prevent lining failure caused by long-term frictional abrasion.
