The service life of a screw conveyor depends in part on the wear resistance of its screw flights. During operation, the flights are exposed to continuous contact with conveyed materials, which can cause abrasive wear, impact damage, and localized loading. Wear becomes more severe when the conveyor handles highly abrasive materials such as sand, mineral powders, and cement clinker.
Improving flight wear resistance requires selecting suitable materials and surface treatments based on the material properties, operating speed, and actual wear locations. Several methods can be used.
Select more wear-resistant materials
For screw conveyors handling highly abrasive materials, wear-resistant steel plates can be used to manufacture the screw flights. These materials provide better resistance to particle abrasion and surface cutting.
Common options include AR235, AR400, and AR500 wear-resistant steel plates, as well as other wear-resistant alloys. Chromium carbide overlay plates can also be considered for applications with severe abrasive wear.
Material selection should not be based on hardness alone. Toughness and impact resistance must also be considered. When the conveyed material contains large, hard particles, the screw flights may experience both continuous abrasion and particle impact. The selected material should therefore provide a suitable balance between wear resistance and impact resistance.
Apply hardfacing or surface treatments
Hardfacing is a common method of improving the wear resistance of screw flights. A layer of wear-resistant alloy is deposited onto the flight surface by welding, reducing direct abrasive contact with the base material.
Hardfacing is usually applied to the material-contacting surface of the screw flights. When the conveyed material is particularly abrasive, the back of the flights, outer edges, and external surface of the center pipe can also receive targeted treatment, depending on the actual wear pattern.
Other surface treatments, such as flame hardening and thermal spraying, can also be considered according to the base material and operating conditions. These processes differ in their effects on the substrate, coating adhesion, and resulting surface hardness. The appropriate method should be selected based on the material properties and working environment.
Install replaceable wear plates or polymer liners
Replaceable wear plates can be installed on screw flights where localized wear is particularly severe. These may be made of wear-resistant steel or reinforced polymer materials.
The additional wear layer protects the flight substrate from direct contact with the conveyed material. When the wear plate reaches its replacement limit, it can be removed and replaced separately. This avoids replacing the entire screw flight assembly and helps reduce maintenance costs.
Wear-resistant steel plates are more suitable for applications involving severe abrasive wear or impact loads. Polymer wear liners require careful consideration of operating temperature, material compatibility, fixing methods, and impact resistance. They are not suitable for every conveying application.
Apply wear-resistant coatings
Applying a wear-resistant coating to the screw flight surface is another way to improve its resistance to wear.
Depending on the working environment, coatings can be applied by brushing, spraying, or other suitable processes. Important selection factors include adhesion to the metal substrate, resistance to abrasive wear, operating temperature, and impact resistance.
In conveyors handling abrasive particles continuously, the coating must withstand long-term friction and particle impact. A coating with high hardness but insufficient toughness, or poor adhesion to the substrate, may crack or peel during operation. The coating material and application process should therefore be selected according to the actual operating conditions.
Adjust screw conveyor operating parameters
The operating parameters of a screw conveyor also affect the wear rate of its flights. Material selection and surface treatments alone may not be sufficient when the equipment operates under severe abrasive conditions.
Where the required conveying capacity allows, reducing screw speed and trough fill level can help limit relative friction between the material and flights, as well as particle impact. The screw diameter, flight thickness, and clearance between the flights and casing should also match the material properties to prevent local contact and abnormal wear.
During routine maintenance, the working surfaces, outer edges, and ends of the flights should be inspected regularly. When the flight thickness has decreased significantly, or when local deformation or damage to welded areas is found, the affected parts should be repaired or replaced. This helps prevent further wear from affecting conveying capacity and equipment operation.
Custom machining of screw flights and related components
Screw flights and other components vary in dimensions, structural design, and installation requirements depending on the conveyor specifications. For non-standard equipment, we can manufacture custom screw shafts, connecting parts, support housings, and other precision structural components according to customer drawings. Both single-piece and small-batch production are available.
Hansheng Automation also provides precision machining for components used in various industries. These include structural parts for yachts, precision components for RC racing cars, and functional parts for tobacco packaging and filling machinery. We manufacture custom components according to customer-supplied engineering drawings and dimensional requirements.
