In the paper industry, pulping, dewatering, and pressing processes place extremely high demands on equipment reliability and continuous operation. The paper mill screw press, as a critical core component, directly affects dewatering efficiency, energy consumption, and overall production stability. To address severe wear problems under heavy-duty operating conditions, PTA welding technology has become a widely recognized and effective wear protection solution in the paper industry.
Operating Conditions and Wear Mechanisms of Paper Mill Screw Press
Paper mill screw presses typically operate under high torque and high pressure while continuously processing high-consistency pulp. The pulp contains large amounts of fibers, fine sand, and other impurities, combined with moisture and chemically active media.
In actual operation, screw presses are mainly subjected to the following wear mechanisms:
• Abrasive wear caused by fibers and sand particles
• Erosive wear due to high-velocity pulp flow
• Corrosive wear resulting from moisture and chemical substances
The combined effect of these factors leads to thinning of screw flights, dimensional loss, reduced pressing efficiency, and, in severe cases, premature equipment replacement.
Limitations of Conventional Wear Protection Methods
Traditional paper mill screw presses are usually manufactured from high-strength steel or protected by conventional hardfacing methods. However, under continuous heavy-load operation, these approaches often show clear limitations:
• High dilution rate reduces actual wear resistance
• Non-uniform weld layers with risk of cracking or spalling
• Short service life and frequent maintenance
• High cost and long downtime for complete replacement
As a result, paper mills increasingly require a stable, long-lasting, and repairable wear protection technology.
PTA Welding Technology Principles and Process Characteristics
PTA welding (Plasma Transferred Arc hardfacing) is a high-precision surface engineering technology. It uses a plasma arc as a concentrated heat source to deposit wear-resistant alloy powder onto the base material, forming a dense hardfacing layer with strong metallurgical bonding.
Key characteristics of PTA welding include:
• Low dilution and stable alloy composition
• Small heat-affected zone and minimal distortion
• Dense, uniform microstructure
• High level of automation and repeatability
These advantages make PTA welding especially suitable for high-value, heavy-duty components such as paper mill screw presses.
Application of PTA Welding on Paper Mill Screw Press
In paper mill screw press applications, PTA welding is primarily applied to screw flights and other high-wear areas. Depending on pulp characteristics and operating conditions, different hardfacing alloys such as high-chromium alloys, nickel-based alloys, or customized wear-resistant materials can be selected.
After PTA welding treatment:
• Surface hardness and wear resistance of screw flights are significantly improved
• Resistance to abrasive and erosive wear is greatly enhanced
• Stable performance is maintained under high-consistency pulp conditions
This effectively ensures long-term reliable operation of the screw press.
Service Life Improvement of Screw Press with PTA Welding
Extensive field experience shows that paper mill screw presses treated with PTA hardfacing typically achieve a service life increase of 2 to 3 times or more. Maintenance intervals are extended, and unplanned shutdowns are significantly reduced.
This leads to lower spare parts consumption, reduced maintenance labor, and improved equipment availability for paper mills.
Advantages of PTA Welding in Screw Press Repair and Remanufacturing
In addition to new component protection, PTA welding is widely used for screw press repair and remanufacturing. Worn screw presses with sound base material can be rebuilt to original dimensions and further upgraded with enhanced wear resistance.
Compared with full replacement, PTA welding remanufacturing offers:
• Lower overall cost
• Shorter repair cycle
• Upgraded performance after repair
• Higher resource utilization
This approach aligns with the paper industry’s goals of sustainable manufacturing and cost optimization.
PTA Welding Supporting Efficient and Stable Paper Mill Operations
As paper mill equipment continues to move toward larger scale, higher speed, and continuous operation, performance requirements for critical wear components will continue to rise. PTA welding technology for paper mill screw press applications provides a proven and reliable technical solution to severe wear challenges.
With ongoing improvements in hardfacing alloy systems and automated PTA welding equipment, this technology will play an increasingly important role in extending equipment life, reducing total operating costs, and ensuring stable paper production.
Post time: Jan-15-2026