CLADDING TECHNOLOGY SHANXI CO., LTDTubular Wire Overlay Welding in the Non-Woven Fabric Industry
Literature Overview
This 1998 paper by Pang Ming and Fu Wenlong, published in the journal Industrial Textiles, examines the application of flux-cored wire (tubular wire) overlay welding in the non-woven fabric manufacturing industry. The study addresses a specific industrial need: the production of wear-resistant and corrosion-resistant components used in textile processing machinery, where overlay welding provides a cost-effective means of applying specialized surface layers to carbon steel substrates.
Industry Context and Technical Requirements
The non-woven fabric industry relies on a variety of metal components including guide rollers, feed rollers, heated plates, and forming drums. These components are exposed to abrasive fiber particles, chemical additives, and elevated temperatures. Traditional approaches involved either using expensive specialty alloy materials for the entire component or applying post-fabrication coatings. Overlay welding with flux-cored wire offered a middle ground: a carbon steel base component with a wear- and corrosion-resistant overlay layer applied during or after fabrication.
Process Characteristics of Flux-Cored Wire Overlay
Flux-cored arc welding (FCAW) uses a tubular wire containing flux powder inside a metal sheath. When the arc is struck, the flux powder melts to form a slag layer and shielding gas, protecting the molten weld pool. This self-shielding characteristic makes FCAW suitable for outdoor and field applications without external gas protection. In overlay welding applications, the wire composition is tailored to deposit the desired surface properties.
| Parameter | Typical Value for Overlay Application |
|---|---|
| Wire type | Self-shielded or gas-shielded flux-cored wire |
| Wire diameter | 1.2–1.6 mm |
| Voltage | 22–30 V |
| Current | 150–280 A |
| Travel speed | 200–500 mm/min |
| Layer thickness per pass | 1.5–3.0 mm |
| Shielding gas (if gas-shielded) | CO2 or Ar + CO2 mixture |
Application Scenarios in Textile Machinery
The study identified several key application scenarios:
- Roller surface hardening: Guide rollers and feed rollers in non-woven fabric lines experience continuous sliding contact with fabric webs. Overlay layers of hardfacing material extend roller life significantly.
- Corrosion-resistant heating surfaces: Heated forming plates and drums are exposed to moisture and chemical vapors. Overlay layers of stainless steel or nickel-based alloys provide corrosion protection.
- Wear-resistant guide components: Metal guides and deflectors that direct fabric webs are subject to abrasion from fibers and particles. Overlay welding extends their service interval.
Performance Evaluation
The study evaluated overlay layers deposited with different flux-cored wire compositions, including high-carbon hardfacing wires, stainless steel wires, and nickel-based alloy wires. The evaluation criteria included hardness, wear resistance, corrosion resistance, and bond strength to the carbon steel base.
| Wire Type | Hardness (HV) | Wear Index | Corrosion Resistance | Bond Strength |
|---|---|---|---|---|
| High-carbon hardfacing | 450–600 | High | Moderate | Good |
| Stainless steel (308L equivalent) | 200–280 | Moderate | Good | Good |
| Nickel-based alloy | 250–350 | High | Excellent | Good |
The study found that the choice of wire composition must be matched to the specific service condition. For purely abrasive wear, high-carbon hardfacing wires provided the best wear resistance. For combined wear and corrosion conditions, nickel-based alloy wires offered the best overall performance. Stainless steel wires were suitable where corrosion resistance was the primary concern but wear was moderate.
Process Optimization and Defect Control
The study discussed several process optimization strategies:
- Preheating: Base metal preheating to 100–150°C reduces residual stresses and minimizes cracking risk, particularly for high-alloy overlay wires.
- Interpass temperature control: Maintaining interpass temperature below 250°C prevents excessive grain growth and maintains the beneficial microstructure of the overlay layer.
- Layer sequencing: For thick overlay layers, a graded layer approach was recommended, with a transition layer between the base metal and the final hardfacing layer to reduce dilution effects.
- Travel pattern: Overlapping stringer beads with 50–70% overlap ensures uniform coverage and minimizes undercutting.
Common defects identified included undercutting at bead edges, porosity in the overlay layer, and cracking at the overlay-base interface. The study recommended adjusting wire feed speed, travel speed, and voltage to minimize these defects, and emphasized the importance of base metal cleanliness before overlay welding.
Engineering Practice Implications
This study is notable for its industry-specific focus, bridging the gap between general welding technology and a specific manufacturing sector. The non-woven fabric industry has particular requirements that differ from those of pressure vessels or structural components. The study demonstrates that overlay welding can be adapted to serve diverse industrial needs, provided the process parameters and wire selection are properly matched to the service conditions.
For today's practitioners, the study's recommendations remain relevant. The use of flux-cored wire for overlay welding is still common in many industries, and the principles of wire selection, process optimization, and defect control have not changed. The study also highlights the value of industry-specific research: understanding the specific wear and corrosion mechanisms in a given application is essential for selecting the appropriate overlay material and process.