In industries such as chemical processing, mining, power generation, seawater desalination, and oil transportation, Fiberglass Reinforced Plastic (FRP) pipes have been widely used due to their lightweight structure, corrosion resistance, and convenient installation.

However, as industrial operating conditions become increasingly demanding—especially under:

• High wear conditions;

• High-pressure transportation;

• Temperature fluctuations;

• Strong corrosive environments;

a common failure issue of FRP pipes has become increasingly noticeable:

Delamination.

Unlike traditional metal pipes, FRP pipes are composite structures made of resin and glass fiber reinforcement. Their performance depends heavily on the bonding quality between different layers. Once the bonding between layers fails, problems may occur, including:

• Internal layer separation;

• Reduced mechanical strength;

• Leakage or sudden pipe failure;

• Shortened service life.

For industrial pipeline systems requiring long-term stable operation, overall lifecycle reliability is more important than initial purchase cost.

Steel-Nylon Composite Pipe was developed to address the long-term operational challenges faced by traditional composite pipelines.

1. Why Does FRP Pipe Experience Delamination?

1.1 The Interface Between Resin and Glass Fiber Is a Potential Weak Point

FRP pipes are mainly composed of:

• Glass fiber (providing structural strength);

• Resin matrix (providing bonding and corrosion resistance).

In theory, these two materials form a high-performance composite structure. However, the interface between resin and glass fiber remains the most vulnerable area during long-term service.

When pipelines experience continuous:

• Internal pressure fluctuations;

• Temperature cycling;

• External vibration;

• Medium impact;

different expansion rates between materials generate internal stresses.

Over time, these stresses accumulate and cause:

Fiber-resin separation → Layer delamination.

2. High-Temperature Conditions Accelerate FRP Pipe Delamination

Many industrial applications do not operate under room temperature conditions.

Typical examples include:

• Chemical mother liquor transportation;

• Alkali solution pipelines;

• Salt chemical systems;

• Hot water circulation systems.

Operating temperatures can reach 60°C or higher.

Under long-term high-temperature exposure, resin materials may experience:

• Reduced mechanical strength;

• Accelerated aging;

• Lower toughness;

• Decreased interlayer bonding strength.

Especially under repeated heating and cooling cycles:

Heating → Material expansion
Cooling → Material contraction

Continuous thermal cycling creates fatigue stress inside the composite structure.

Eventually:

The pipe may appear normal externally while internal delamination has already started.

3. Abrasive Media Can Damage FRP Pipe Structures

FRP pipes are often used for transporting:

• Mining tailings;

• Slurry;

• Fly ash;

• Chemical slurry.

These media usually contain:

• Quartz particles;

• Solid particles;

• Salt crystals;

• Mineral materials.

During high-speed transportation, continuous erosion occurs on the inner pipe wall.

Although FRP pipes have good corrosion resistance, their wear resistance mainly relies on the protective resin layer.

Once the resin layer is worn away:

↓

Glass fibers become exposed

↓

Fibers suffer direct impact

↓

Layer structure gradually weakens

↓

Delamination or leakage may occur

Therefore, in highly abrasive applications, the service life of FRP pipes can be significantly affected.

4. Pipe Connection Areas Are High-Risk Locations for FRP Failures

FRP pipes are commonly connected by:

• Flange connections;

• Adhesive joints;

• Socket connections.

Due to the relatively rigid nature of FRP materials, installation factors such as:

• Uneven flange loading;

• Excessive bolt tightening force;

• Foundation settlement;

may create localized stress concentration.

For large-diameter pipeline systems:

such as DN800 and above,

connection areas experience more complex mechanical loads.

After long-term operation, problems may appear near joints:

• Micro cracks;

• Layer separation;

• Leakage.

5. Why Is FRP Pipe Delamination Difficult to Detect?

When steel pipes fail, problems are usually visible:

• Corrosion points;

• Wall thickness reduction;

• Leakage locations.

However, FRP pipe failures often occur internally.

The external surface may still appear intact while internal damage has already developed:

• Resin cracking;

• Fiber debonding;

• Multi-layer separation.

This makes it difficult for maintenance teams to identify risks early.

Once severe delamination occurs:

the entire pipe section may need replacement.

6. How Does Steel-Nylon Composite Pipe Solve Traditional Composite Pipe Problems?

To overcome the limitations of traditional pipeline materials, Steel-Nylon Composite Pipe adopts a unique structure:

Steel reinforcement layer + High-performance nylon lining

Unlike FRP pipes, which rely on multi-layer fiber reinforcement, Steel-Nylon Composite Pipe uses:

• Steel structure for mechanical strength;

• Nylon lining for corrosion resistance and wear protection.

6.1 Steel Structure Provides Reliable Pressure Resistance

The external steel layer carries the main structural load.

Advantages include:

• High pressure resistance;

• Excellent impact strength;

• Suitable for large-diameter applications;

• Stable performance in long-distance transportation.

Current product capability:

• Diameter range: DN100-DN2000+

• Pressure rating: 1.0-4.0 MPa

Meeting the requirements of large-scale industrial pipeline systems.

6.2 Nylon Lining Provides Excellent Corrosion and Wear Resistance

The nylon inner layer provides:

• Acid and alkali resistance;

• Salt resistance;

• Wear resistance;

• Non-metallic corrosion protection.

Compared with traditional materials:

• Carbon steel requires corrosion protection;

• Stainless steel has high cost;

• FRP may face delamination risks.

Steel-Nylon Composite Pipe achieves a balanced combination of:

Strength + Corrosion Resistance + Wear Resistance.

6.3 Integrated Structure Reduces Delamination Risks

The biggest challenge of traditional composite materials is:

Long-term bonding stability between different layers.

Steel-Nylon Composite Pipe adopts advanced manufacturing technology to achieve:

• Strong bonding between nylon lining and steel structure;

• No fiberglass layer separation mechanism;

• Reduced long-term delamination risk.

It is especially suitable for:

• Strong alkaline environments;

• Salt chemical industries;

• Mining slurry transportation;

• High-wear applications.

7. FRP Pipe vs Steel-Nylon Composite Pipe Comparison

Comparison	FRP Pipe	Steel-Nylon Composite Pipe
Structure	Multi-layer fiberglass and resin	Steel reinforcement + nylon lining
Delamination Risk	Possible layer separation	No fiberglass layer delamination
Wear Resistance	Moderate	Excellent
Impact Resistance	Limited	Strong
Large Diameter Application	Limited by manufacturing process	Available up to DN2000+
High Pressure Application	Relatively limited	Up to 4.0 MPa
Maintenance Cycle	Affected by wear and aging	Longer service life
Connection Method	Specialized installation required	Integrated flange connection available

8. Industries Where Steel-Nylon Composite Pipe Performs Best

8.1 Chemical Industry

Applications:

• Caustic soda transportation;

• Brine systems;

• Carbonate solutions;

• Chemical mother liquor pipelines.

Advantages:

Excellent corrosion resistance while reducing leakage risks caused by metal corrosion.

8.2 Mining Industry

Applications:

• Tailings transportation;

• Ore slurry pipelines;

• Backfilling systems.

Advantages:

Excellent abrasion resistance and longer maintenance intervals.

8.3 Power Generation Industry

Applications:

• Desulfurization slurry pipelines;

• Ash transportation;

• Cooling water systems.

Advantages:

Reduced pipeline replacement frequency and lower maintenance costs.

9. Conclusion: Pipeline Selection Should Focus on Lifecycle Value, Not Only Initial Cost

The delamination problem of FRP pipes is essentially a challenge related to the long-term stability of composite materials.

FRP pipes still have advantages in general corrosion environments.

However, for applications involving:

• High abrasion;

• High pressure;

• Large diameter;

• Long-distance transportation;

• Strong corrosive media;

pipeline materials must focus on:

Long-term reliability, maintenance costs, and total lifecycle value.

Steel-Nylon Composite Pipe combines:

• Steel strength for structural stability;

• Nylon performance for corrosion and wear resistance.

It provides a more reliable solution for demanding industrial transportation systems.

The future of industrial pipelines is not only about corrosion resistance, but about:

Longer service life, lower maintenance requirements, and safer operation.