In demanding industrial environments, screw flights are continuously exposed to abrasion, corrosion, and impact. Over time, this leads to material loss, reduced efficiency, and costly downtime.
Instead of replacing worn components, PTA hardfacing (Plasma Transferred Arc welding) offers a cost-effective way to restore dimensions, improve wear resistance, and extend service life. This guide explains how PTA hardfacing works, where it applies, and how to choose the right solution for your equipment.
What Is PTA Hardfacing?
PTA (Plasma Transferred Arc) hardfacing is an advanced welding process that uses a high-temperature plasma arc to melt metal powder and deposit it onto a substrate. The result is a metallurgically bonded, high-density wear-resistant layer.
With temperatures reaching up to 23,000°F, PTA enables strong bonding, minimal dilution, and precise control. It is widely used for high-wear industrial components, especially screw flights requiring thick, durable coatings.
Why Apply PTA Hardfacing to Screw Flights?
Screw flights are essential in equipment such as screw conveyors, decanter centrifuges, and dewatering systems. These components face continuous abrasive and corrosive conditions, leading to rapid wear.
PTA hardfacing is widely used in industrial screw flight repair solutions to restore performance and extend lifespan.
PTA hardfacing allows you to:
- • Restoring original dimensions
- • Adding a high-hardness protective layer
- • Extending service life significantly
- • Reducing downtime and replacement costs
This makes it a “repair + performance upgrade” solution rather than just maintenance.
What Are the Common Wear Problems of Screw Flights?
Screw flights typically experience multiple wear mechanisms:
Abrasive wear
Hard particles (sand, minerals, fibers) erode the surface, reducing thickness and conveying efficiency.
Impact wear
Large or heavy materials cause edge chipping, cracks, and localized damage.
Corrosion and thermal damage
Chemical media and high temperatures reduce hardness and accelerate material degradation.
Deformation
Overload or uneven stress can cause bending or misalignment, affecting system stability.
Without timely repair, these issues lead to efficiency loss, higher energy consumption, and equipment failure.
What Advantages Does PTA Hardfacing Offer for Screw Flights?
PTA hardfacing delivers several key advantages:
Metallurgical bonding
Creates a strong bond with the base metal, outperforming coatings in durability and impact resistance.
Flexible material selection
- Nickel-based alloys: balanced wear resistance and toughness
- Cobalt-based alloys: high-temperature and impact resistance
- Tungsten carbide (WC/Ni): extreme wear resistance (up to 3–10× life improvement)
Thick coating with low distortion
Allows controlled deposition of thick layers while maintaining the original screw geometry.
Restoration + enhancement
Not only repairs worn screw flights but often improves performance beyond original specifications.
Cost efficiency
Typically 30–50% of replacement cost, with much shorter turnaround time.
Which Wear-Resistant Materials Are Suitable for PTA Hardfacing of Screw Flights?
Material selection depends on operating conditions:
Nickel-based alloys
Good all-around performance with wear resistance and crack resistance.
Cobalt-based alloys (Stellite type)
Ideal for high-temperature, high-impact environments.
Tungsten carbide (WC/Ni)
Extremely hard and wear-resistant, suitable for severe abrasive conditions.
Customized alloys
Tailored solutions (Ni-B, Fe-Cr systems, multilayer structures) for specific media and environments.
Engineering tip:
Combine hard layers + buffer layers to balance hardness and toughness, reducing cracking risk.
In Which Industries Is PTA Hardfacing for Screw Flights Used?
PTA hardfacing is widely used across industries where screw flights face wear:
- Plastic and rubber extrusion (extruder screws)
- Paper and pulp processing (dewatering screw flights)
- Chemical and pharmaceutical industries
- Mining and construction materials handling
- Food and feed processing
- Wastewater and sludge treatment systems
Any application involving abrasion, corrosion, or particle impact is a strong candidate for PTA hardfacing.
What Is the PTA Hardfacing Process for Repairing Screw Flights?
The repair process typically includes:
Inspection and evaluation
Assess wear level, dimensions, and material condition.
Surface preparation
Clean, grind, and correct deformation; apply a bonding layer if needed.
Automated PTA welding
Use CNC or robotic systems to deposit material along the helical path.
Typical layer thickness: 0.5–1.0 mm per pass, usually 1–3 layers.
Post-processing
Grinding, machining, and polishing to restore original geometry and surface quality.
Strict process control ensures consistent quality and precise dimensional recovery.
What Are the Advantages of PTA Hardfacing Compared with Other Repair Methods for Screw Flights?
Compared to traditional welding and thermal spraying:
Higher performance coatings
Denser, more wear-resistant, and better impact resistance.
Lower thermal impact
Minimal distortion and reduced risk of cracking.
Higher precision
Automated welding ensures uniform thickness and consistent quality.
Better cost-performance ratio
Faster processing and lower overall cost than replacement or laser cladding in many cases.
These advantages make PTA hardfacing a preferred solution for high-wear screw flight repair.
Contact and Consultation (CTA)
If you are looking for PTA hardfacing services for screw flights, our engineering team can support you with:
- Free wear analysis and repair evaluation
- Customized alloy selection
- Automated precision welding
- Long-term performance optimization
Contact: Shanghai Duomu Industrial Co., Ltd.
Technical Support: +86-15021996700 (WeChat / WhatsApp)
For more details, contact us for PTA hardfacing and get a customized solution.
We help you reduce maintenance costs, extend equipment life, and improve operational efficiency.
Frequently Asked Questions (FAQ)
Q1: What is PTA hardfacing?
A welding process that deposits wear-resistant alloy onto a surface using a plasma arc.
Q2: How much can service life be extended?
Typically 3–10 times longer in severe wear conditions.
Q3: Is special equipment required?
Yes, including PTA welding systems, powder feeders, and CNC/robotic controls.
Q4: PTA vs. laser cladding?
PTA allows thicker layers and lower cost, making it ideal for heavy wear applications.
Q5: What materials are suitable?
Carbon steel, alloy steel, and other weldable substrates.
Q6: Is machining required after welding?
Yes, for restoring precise dimensions and surface finish.
Q7: How long does repair take?
Usually a few days, depending on quantity and wear level.
Q8: Is PTA hardfacing expensive?
No—typically much cheaper than replacement, with better ROI.
Post time: Apr-23-2026