Plasma Powder Hardfacing for Plastic Extruder Screw: Improving Wear Resistance and Service Life

In plastic processing equipment, the screw is one of the most critical components responsible for material conveying, melting, and mixing during the extrusion process. However, due to continuous friction, high temperature, and corrosive plastic additives, screw components often experience significant wear.

To solve this problem, plasma powder hardfacing for plastic extruder screw has become an effective surface reinforcement technology. By applying plasma powder hardfacing for plastic extruder screw, wear-resistant alloy materials are metallurgically bonded to the screw surface, significantly improving durability and operational stability.

Through plasma powder hardfacing for plastic extruder screw reinforcement, manufacturers can extend the service life of extruder screws while reducing equipment downtime and maintenance costs.

Why Extruder Screws Wear Out Quickly

Plastic extrusion screws operate under demanding conditions involving continuous rotation, high pressure, and elevated temperatures. Over time, these working conditions can lead to severe wear on the screw surface.

Common causes of screw wear include:

• Abrasive fillers in plastic materials
• High-temperature processing environments
• Chemical corrosion from additives
• Mechanical friction between screw and barrel

Most extruder screws are manufactured from 38CrMoAl nitriding steel or 42CrMo alloy steel, which provide good mechanical properties and heat treatment performance. However, even these materials may experience significant wear after long periods of operation.

Using plasma powder hardfacing for plastic extruder screw repair allows manufacturers to restore worn screws and significantly improve their resistance to abrasion and corrosion.

Typical Repair Methods for Extruder Screws

When extruder screws are damaged or worn, several repair techniques can be used depending on the severity of wear.

1. Manufacturing New Screws for Broken Shafts

If a screw shaft is twisted or broken, the new screw must be manufactured based on the actual inner diameter of the barrel, ensuring the correct clearance between the screw and the barrel.

2. Thermal Spraying Tungsten Carbide

For worn screw diameters, the surface can be treated with thermal spraying of tungsten carbide alloys, followed by precision grinding to restore the required dimensions.

3. Tungsten Carbide Hardfacing

Another common method involves depositing 1–2 mm thick tungsten carbide alloy layers on worn thread sections, followed by machining to restore the screw geometry.

This alloy typically contains elements such as:

• Carbon (C)
• Chromium (Cr)
• Vanadium (V)
• Cobalt (Co)
• Tungsten (W)
• Boron (B)

These elements significantly improve wear resistance and corrosion resistance.

4. Hard Chrome Plating

Hard chromium plating can also be applied to the screw root diameter to increase surface hardness. However, chromium coatings may peel off under heavy wear conditions.

Compared with these traditional methods, plasma powder hardfacing for plastic extruder screw provides stronger bonding strength and longer service life.

Plasma Hardfacing Process for Extruder Screws

The plasma powder hardfacing for plastic extruder screw process uses a plasma arc heat source to melt alloy powder and the screw surface simultaneously, creating a dense and durable cladding layer.

Hardfacing Materials

Commonly used hardfacing materials include:

• Nickel-based alloy powders such as Ni60
• Nickel-based carbide alloys

These materials provide excellent resistance to wear, corrosion, and high temperature.

Powder Selection Requirements

When selecting alloy powders, several factors must be considered:

• The powder should match the performance requirements of the product, including wear resistance and corrosion resistance.
• The thermal expansion coefficient of the alloy powder should be close to that of the base material to avoid cracking caused by thermal stress.
• Self-fluxing powders with good flow properties are preferred for stable cladding results.

Typical powder parameters include:

• Powder feeding speed: 10–30 g/min
• Powder particle size: 80–120 mesh
• Gas flow rate: 1.0–2.0 L/min

These parameters help maintain stable cladding performance and uniform coating quality.

Screw Surface Preparation Requirements

Before performing plasma powder hardfacing for plastic extruder screw, the screw surface must be carefully prepared.

Key requirements include:

• The screw surface must be free of oil and grease
• Rust and oxidation layers must be removed
• The surface must be clean and free from major defects

Proper surface preparation ensures strong metallurgical bonding between the cladding layer and the base metal.

Advantages of Plasma Hardfacing Technology

Applying plasma powder hardfacing for plastic extruder screw reinforcement offers several advantages compared with conventional repair methods.

Strong Metallurgical Bond

The cladding layer is metallurgically bonded to the base metal, ensuring excellent adhesion and durability.

Superior Wear Resistance

The tungsten carbide and nickel alloy layers significantly increase surface hardness and wear resistance.

Improved Corrosion Protection

The alloy coating protects the screw from corrosive additives used in plastic processing.

Longer Service Life

With proper reinforcement, plasma powder hardfacing for plastic extruder screw can greatly extend the lifespan of plastic processing equipment.

Improving Plastic Machinery Reliability with Surface Engineering

As plastic processing technology continues to evolve, equipment durability has become increasingly important for manufacturers. Advanced surface engineering methods provide an efficient way to improve the performance of critical components.

Because of its excellent wear resistance, strong bonding strength, and cost-effective repair capability, plasma powder hardfacing for plastic extruder screw has become a preferred solution for extending the life of extruder screws in plastic machinery.

At FNS Pipeline Technology Co., Ltd., advanced cladding technologies are used to provide reliable wear-resistant solutions for industrial components operating in demanding environments.