High-Temperature Wear-Resistant Clad Pipes for DRI/HBI Conveying: A Solution for 650–850°C Service
Direct Reduced Iron (DRI) and Hot Briquetted Iron (HBI) conveying is one of the most demanding applications in modern metallurgical plants. With material temperatures reaching approximately 650–850°C, combined with hard, angular particles and continuous high-velocity abrasion, conventional heat-resistant steel pipes can suffer rapid wall thinning, leakage and unplanned shutdowns. High-temperature wear-resistant clad pipes provide a more durable approach by combining a heat-resistant steel substrate with a metallurgically bonded wear-resistant alloy layer engineered for severe conveying conditions.
For DRI/HBI systems, the challenge is not simply finding a material that can tolerate high temperature. The internal surface must also withstand abrasive particle impact, sliding wear, thermal cycling and prolonged exposure to a hot, aggressive process stream. This makes material selection, cladding metallurgy and manufacturing consistency critical to long-term pipeline reliability.
Why DRI and HBI Conveying Is So Abrasive
DRI is produced at elevated temperatures and is transported through pipes, elbows, chutes and transfer sections under demanding operating conditions. The particles can have sharp edges and considerable hardness, creating several simultaneous wear mechanisms:
Abrasive wear: hard particles continuously remove material from the pipe wall.
Impact wear: particles strike the internal surface at changes in direction and flow velocity.
Sliding wear: continuous particle movement gradually cuts and polishes the surface.
Thermal cycling: repeated heating and cooling creates thermal stresses within the pipe.
Localized erosion: elbows and other flow-direction changes can experience significantly higher wear rates than straight pipe sections.
A conventional heat-resistant pipe may survive the temperature but still lose wall thickness rapidly because its surface hardness and wear resistance are insufficient for the conveying medium.
This is why a high-temperature conveying line should be evaluated as a combined thermal-and-wear problem, rather than a simple high-temperature piping application.
Why High-Temperature Wear-Resistant Clad Pipes Are Different
The basic concept behind a clad pipe is straightforward: use a heat-resistant structural material for the pipe body and apply a specially selected alloy to the internal surface where severe wear occurs.
For demanding DRI/HBI applications, FNS develops high-temperature wear-resistant clad pipes using a heat-resistant stainless steel substrate, such as 310S, combined with a wear-resistant multi-alloy cladding system.
The substrate provides the required structural and thermal performance, while the internal cladding is designed to withstand aggressive particle abrasion.
More importantly, the cladding is metallurgically bonded to the substrate. This creates a fundamentally different failure mechanism from mechanically attached liners or bonded ceramic components.
Metallurgical Bonding Matters
A properly deposited cladding layer forms a metallurgical interface with the base metal rather than simply sitting on top of it.
This offers several advantages:
- Reduced risk of delamination
- Better resistance to thermal cycling
- Strong interface integrity
- Stable performance under impact
- Ability to machine the deposited layer when required
- More reliable long-term operation than loosely attached wear liners
For high-temperature DRI conveying, this distinction can be critical. A wear layer that performs well at room temperature may not remain reliable when exposed to repeated thermal expansion, contraction and particle impact.
High temperature wear resistant clad pipe for DRI conveying
FNS Multi-Alloy Wear Cladding for High-Temperature Service
FNS Pipeline Technology Co., Ltd. focuses on surface engineering solutions for demanding industrial components and pipeline applications.
For high-temperature wear applications, the cladding composition can be engineered around the actual operating environment. A multi-alloy system incorporating elements such as chromium, molybdenum, niobium, tungsten and vanadium can be selected to improve the combination of hardness, wear resistance and high-temperature stability.
The objective is not simply to maximize hardness.
An effective wear layer must maintain an appropriate balance between:
- Hardness
- Toughness
- High-temperature stability
- Resistance to abrasive cutting
- Resistance to impact
- Metallurgical bonding
- Thermal compatibility with the substrate
This balance is particularly important in DRI/HBI conveying systems, where excessive brittleness can create a different failure problem.
FNS Manufacturing Approach
The performance of a clad pipe depends not only on the alloy chemistry but also on how consistently the cladding is deposited.
A typical FNS manufacturing route includes several controlled stages.
1. Substrate Selection
The pipe substrate is selected according to the operating temperature, pressure, geometry and mechanical requirements.
For high-temperature conveying applications, heat-resistant stainless steels such as 310S may be considered where appropriate.
2. Internal Surface Preparation
Before cladding, the internal surface must be properly prepared.
Contamination such as oil, rust, scale and other surface defects can compromise bonding quality. The surface preparation process therefore aims to establish a clean and suitable metallurgical surface.
3. Controlled Internal Cladding
The wear-resistant alloy is deposited onto the internal bore using controlled automated cladding equipment.
Process parameters are adjusted according to:
- Pipe diameter
- Wall thickness
- Cladding alloy
- Required deposition thickness
- Heat input
- Travel speed
- Powder or wire characteristics
- Final machining allowance
Automated deposition helps maintain more consistent layer thickness and surface quality across the working area.
4. Cooling and Stress Control
Thermal management is particularly important when cladding high-temperature components.
Excessive heat input can increase distortion and residual stress, while insufficient fusion can compromise bonding. The manufacturing process therefore needs to balance deposition efficiency with metallurgical quality.
5. Inspection and Machining
After deposition, the cladding layer can be inspected and, where required, machined to the specified dimensions.
Depending on the project requirements, inspection may include dimensional checks, visual inspection, hardness testing and suitable non-destructive examination.
The final product is therefore not simply a coated pipe—it is an engineered wear-resistant internal surface designed around the customer’s operating conditions.
Why Clad Pipes Can Outperform Ceramic Liners
Ceramic liners have been used extensively in abrasive conveying systems because of their excellent hardness. However, high-temperature DRI/HBI service creates additional challenges.
Ceramic components can be vulnerable to:
- Mechanical impact
- Thermal shock
- Localized cracking
- Joint failure
- Delamination or detachment
- Complicated replacement work
A metallurgically bonded alloy cladding system approaches the problem differently.
Instead of relying on a separate liner attached to the pipe, the wear-resistant layer becomes an integral part of the pipe’s internal surface.
For systems exposed to thermal cycling and mechanical impact, this can provide a significant reliability advantage.
DRI/HBI Pipe Sections Need Different Wear Strategies
Not every part of a conveying system experiences the same wear rate.
Straight pipe sections may primarily experience sliding and abrasive wear, while elbows and transfer sections can experience much more severe localized erosion.
Therefore, simply specifying the same cladding thickness everywhere may not always be the most economical engineering solution.
A more effective approach is to evaluate:
Material temperature → particle characteristics → conveying velocity → impact angle → pipe geometry → expected wear rate → required service life
FNS can use this type of application-based assessment to help determine an appropriate cladding solution for individual pipeline sections.
FNS UAE Project: More Than 12 Months of Stable Operation
A practical example comes from an FNS customer in the United Arab Emirates operating equipment exposed to high-temperature DRI conveying conditions.
The customer had experienced severe wear problems with conventional pipe sections. Rapid internal wear created concerns over wall thinning, leakage and repeated maintenance requirements.
FNS supplied high-temperature wear-resistant clad pipe based on a heat-resistant stainless steel substrate with an internally deposited multi-alloy wear-resistant layer.
Following installation, the FNS clad pipe reportedly achieved more than 12 months of continuous stable operation, with the pipe body remaining in good condition and no reported unplanned shutdown caused by the replaced pipe section during the stated operating period.
The significance of this project was not simply the longer service period. The result demonstrated the value of combining:
heat-resistant substrate + metallurgical cladding + controlled manufacturing + application-specific alloy selection.
For plants where maintenance access is difficult and every shutdown affects production, extending the replacement interval can have a direct impact on operating costs.
Where High-Temperature Wear-Resistant Clad Pipes Can Be Used
Beyond DRI/HBI conveying, similar surface-engineering principles can be applied to other high-temperature abrasive environments.
Potential applications include:
Metallurgical Plants
- DRI conveying pipelines
- Hot material transfer lines
- Furnace material handling systems
- High-temperature chutes
- Abrasive gas-solid conveying equipment
Cement and Mineral Processing
- High-temperature material transfer
- Abrasive powder conveying
- Cyclone-related components
- Chutes and elbows
- Wear-prone transfer sections
Power and Energy
- High-temperature ash handling
- Abrasive particulate conveying
- Boiler-related material handling components
Mining and Heavy Industry
- Abrasive slurry and particulate systems
- Wear elbows
- Transfer pipes
- High-impact conveying components
The correct alloy and substrate should always be selected according to the actual operating environment.
How to Choose a High-Temperature Clad Pipe
Before placing an order, engineers should provide more than pipe diameter and length.
A useful technical specification should include:
| Parameter | Why It Matters |
| Operating temperature | Determines substrate and cladding requirements |
| Maximum temperature | Helps evaluate thermal stability |
| Particle size | Influences impact and abrasive wear |
| Material hardness | Indicates abrasive severity |
| Conveying velocity | Strongly affects erosion rate |
| Pipe diameter | Determines cladding and deposition strategy |
| Elbow radius | Affects localized impact |
| Required service life | Determines wear-layer design |
| Existing failure mode | Helps identify the correct solution |
| Dimensional tolerance | Determines machining requirements |
This information allows the wear-resistant pipe to be engineered around the actual duty instead of using a generic material specification.
Why FNS for High-Temperature Wear Protection?
FNS Pipeline Technology Co., Ltd. combines pipeline engineering with surface-engineering technology to address severe wear and corrosion problems.
Our approach is centered on the principle that the right wear solution begins with the operating condition, not with a generic alloy name.
For high-temperature conveying applications, FNS can provide solutions involving:
- Internal wear-resistant cladding
- High-temperature alloy cladding
- Pipeline component surface engineering
- Wear-resistant elbows and pipe sections
- Customized cladding thickness
- Application-specific alloy selection
- Repair and remanufacturing solutions
The goal is straightforward: reduce premature wear, extend component service life and reduce the frequency of costly shutdowns.
DRI/HBI conveying places extraordinary demands on pipeline components. High temperature alone can challenge conventional materials, while the combination of heat, hard particles, impact and continuous abrasion can accelerate failure dramatically.
High-temperature wear-resistant clad pipes offer an integrated solution by combining a heat-resistant structural substrate with a metallurgically bonded wear-resistant internal layer. Instead of choosing between thermal resistance and wear resistance, the design uses different materials where each performs its most important function.
For plants handling hot DRI, HBI or similarly abrasive materials, the most important question is not simply “How hard is the pipe?” It is:
Can the complete pipe system maintain its mechanical integrity, cladding bond and wear resistance throughout the actual operating cycle?
That is where application-specific cladding engineering can make the difference.
Frequently Asked Questions
1. What is a high-temperature wear-resistant clad pipe?
It is a pipe that combines a heat-resistant substrate with a wear-resistant alloy layer deposited on the internal surface. The two materials are metallurgically bonded to provide improved resistance to high temperature and abrasive wear.
2. Why is clad pipe suitable for DRI/HBI conveying?
DRI and HBI systems can combine high material temperature with severe particle abrasion. A properly engineered clad pipe can address both requirements by using a heat-resistant substrate and a dedicated internal wear layer.
3. What substrate can be used for high-temperature clad pipes?
The substrate depends on the actual operating temperature and mechanical requirements. Heat-resistant stainless steels such as 310S may be suitable for certain high-temperature applications, subject to engineering review.
4. How thick is the wear-resistant cladding?
There is no universal thickness. The required thickness should be determined from operating temperature, particle characteristics, conveying velocity, expected wear rate and required service life.
5. Can FNS manufacture clad elbows?
Yes. Wear is often particularly severe at elbows because the conveying material changes direction. FNS can develop internally clad pipeline components according to the required geometry and service conditions.
6. Is metallurgical bonding better than a ceramic liner?
Neither solution is universally better. Ceramic liners offer excellent hardness, while metallurgically bonded cladding can provide strong interface integrity and better tolerance of certain impact and thermal-cycling conditions. The correct choice depends on the application.
7. Can FNS provide customized alloy compositions?
FNS can evaluate the operating environment and recommend an appropriate alloy system based on wear mechanism, temperature and process conditions rather than applying one material to every application.
8. How can I select the right clad pipe for my DRI system?
Provide FNS with pipe size, operating temperature, material temperature, conveying velocity, particle size, material characteristics, elbow geometry and current failure history. These parameters allow a more meaningful engineering recommendation.
