In plastic extrusion and injection molding machines, the screw and barrel are the core components responsible for conveying, melting, and mixing plastic materials. The performance and lifespan of these components depend heavily on the materials used in manufacturing.
Choosing the right material for a screw barrel can significantly improve wear resistance, corrosion resistance, and overall machine efficiency. In this article, we introduce several commonly used materials for screw barrel manufacturing and explain which ones are best suited for different plastic processing applications.
1. 38CrMoAlA Alloy Steel
38CrMoAlA is one of the most widely used materials for screw barrel manufacturing.
This alloy steel is known for its excellent strength and its ability to undergo nitriding treatment, which significantly increases surface hardness and wear resistance.
Key Features
- High strength and durability
- Excellent nitriding performance
- Surface hardness up to HV900–1000 after nitriding
- Nitriding depth typically 0.5–0.8 mm
Applications
38CrMoAlA nitrided screw barrels are suitable for processing most standard plastic materials, such as:
- Polyethylene (PE)
- Polypropylene (PP)
- Polystyrene (PS)
- ABS
Due to its balanced performance and cost, it remains the most commonly used material in the plastics industry.
2. Bimetallic Alloy Barrel
For applications involving abrasive or corrosive materials, bimetallic barrels provide significantly better performance than standard nitrided barrels.
A bimetallic barrel contains a special wear-resistant alloy layer cast inside the barrel, often including tungsten carbide or other hard alloys.
Key Features
- Extremely high wear resistance
- Excellent corrosion resistance
- Alloy layer thickness typically 1.5–2.5 mm
- Much longer service life than standard barrels
Applications
Bimetallic barrels are recommended for processing:
- Recycled plastics
- Glass fiber reinforced materials
- Plastics with calcium carbonate fillers
- Engineering plastics
These materials can cause severe abrasion to standard nitrided barrels.
3. Tool Steels (H13, DC53)
For certain demanding applications, tool steels such as H13 or DC53 may be used in screw manufacturing.
These steels offer high strength, toughness, and resistance to deformation at high temperatures.
Key Features
- Excellent heat resistance
- High mechanical strength
- Good wear resistance
Applications
Tool steels are commonly used for:
- High-performance screws
- Processing engineering plastics
- Applications requiring high temperature stability
4. Chrome-Plated Screws
In some applications, the screw surface is treated with hard chrome plating to improve corrosion resistance and reduce friction.
Key Benefits
- Improved corrosion resistance
- Smoother surface finish
- Reduced material adhesion
Applications
Chrome-plated screws are often used for processing materials such as:
- PET
- PVC
- Certain engineering plastics
How to Choose the Best Material?
The best material for screw barrel manufacturing depends on several factors:
- Type of plastic material
- Presence of fillers or glass fiber
- Processing temperature
- Production volume and machine load
For standard plastics, 38CrMoAlA nitrided barrels provide an economical and reliable solution.
For abrasive or recycled materials, bimetallic barrels with wear-resistant alloys offer significantly longer service life.
Conclusion
Selecting the right material for screw barrel manufacturing is essential for achieving stable performance and long equipment lifespan. Materials such as 38CrMoAlA nitrided steel, bimetallic alloy barrels, and tool steels each have their own advantages depending on the processing conditions.
By choosing the correct material, manufacturers can improve production efficiency, reduce maintenance costs, and ensure consistent product quality.
Zhoushan Juyuan Machinery Co., Ltd. specializes in manufacturing high-quality screw barrels for plastic extrusion and injection molding machines. We provide customized solutions based on plastic materials, machine models, and production requirements.
Website: https://juyuan-machinery.com/
Email: cxj.job@gmail.com
WhatsApp / WeChat: +86 13905808474