Zhuojin Pipe Fitting Co., LtdArc Surfacing and Special Alloy Electroplating Repair of Paper-Making Dryers and Steam Balls
Literature Overview
This 1999 paper by Liu Jifeng and Li Lin, published in the journal "Surface Technology" (表面技术), presents a hybrid repair technology combining arc surfacing with special alloy electroplating for paper-making dryers (烘缸) and steam balls (蒸球). The technology was implemented at Xinxiang No. 2 Paper Mill and validated through nearly five years of continuous service. The study addresses the unique corrosion and wear challenges faced by rotating drying cylinders in the paper industry, where the operating environment combines high temperature (60-100°C), moisture, and chemical attack from papermaking additives.
Technical Methodology
The repair process employs a two-stage approach:
Stage 1 – Arc Surfacing (打底与填充)
This stage establishes a thick, wear-resistant base layer on the damaged cylinder surface. The surfacing is performed using SMAW or GMAW with nickel-based or cobalt-based alloy electrodes. The surfacing layer serves as both a functional barrier and a substrate for the subsequent electroplating stage. Typical surfacing parameters include:
- Electrode type: Ni-20Cr-15Mo or Co-Cr-W alloy
- Preheat: 200-300°C (to manage thermal shock in the large cylindrical substrate)
- Interpass temperature: ≤250°C
- Number of passes: 3-5 depending on damage depth
- Final surfacing hardness: 40-50 HRC
Stage 2 – Special Alloy Electroplating (特种合金电刷镀)
The electroplating stage deposits a thin (0.05-0.3 mm) functional surface layer that provides corrosion resistance, surface smoothness, and final wear protection. The electroplating solution contains special alloy compositions optimized for the papermaking environment.
Repair Performance Comparison
| Performance Indicator | Before Repair (Baseline) | After Repair (Hybrid Technology) | Improvement |
|---|---|---|---|
| Surface hardness | 120-180 HB (base steel) | 500-650 HV (electroplated surface) | 3-5× increase |
| Corrosion resistance | Degraded, pitting observed | Excellent, no visible corrosion | Qualitative improvement |
| Surface brightness/luster | Dull, oxidized | High gloss, mirror-like finish | Significant improvement |
| Dryer service life | Baseline period | More than 2× extension | >100% extension |
| Paper quality impact | Sticking, surface defects | Clean release, uniform web | Improved product quality |
Metallurgical and Process Analysis
The hybrid approach is particularly effective because it addresses two distinct failure modes simultaneously. Arc surfacing provides bulk material restoration and a hard, wear-resistant transition zone. The electroplating then provides a corrosion-resistant, low-friction surface finish that prevents paper web adhesion and reduces mechanical wear from the felt blanket contact.
The bonding between the electroplated layer and the arc-surfaced substrate is achieved through proper surface preparation: the surfacing layer must be mechanically polished to a smooth, oxide-free surface before electroplating. The electroplating process then creates a metallurgical bond through cathodic deposition at the atomic level, producing a cohesive interface without intermetallic compound formation.
Application-Specific Considerations
Paper-making dryers present unique challenges that distinguish them from other surfacing applications:
- Large diameter – Typical dryer diameters range from 1.5 to 3.5 m, requiring specialized equipment for surface preparation and surfacing
- High operating temperature – Steam heating to 100-180°C creates thermal cycling that can weaken poorly bonded coatings
- Chemical environment – Papermaking effluents contain organic acids, alkalis, and bleaching agents (chlorine-based) that accelerate corrosion
- Surface quality requirements – The cylinder surface directly contacts the paper web; any surface irregularity above 5 μm Ra can cause paper defects
The five-year validation period at Xinxiang No. 2 Paper Mill provides strong evidence of long-term reliability. The technology has since been applied to steam balls (蒸球) used in the pulping process, where even more aggressive chemical conditions prevail.
Study Insights and Reflections
This paper illustrates the power of combining complementary surface engineering technologies to address complex, multi-mode degradation. The arc surfacing provides the structural foundation while the electroplating delivers the functional surface properties. This philosophy of layered surface engineering is applicable across many industrial repair scenarios. The five-year service validation is particularly valuable from a reliability engineering perspective, confirming that the repair technology provides not just initial improvement but sustained performance. For paper mills facing increasing environmental and economic pressures, such repair technologies offer a sustainable alternative to premature equipment replacement, reducing both capital expenditure and environmental impact from steel manufacturing and waste disposal.