Powder Feeding Surfacing Process and Wear-Resistant Composite Steel Plate Applications

Literature Overview

This technical paper by Meng Zhaohong, Yan Zhixing, and Wang Shangxian from the Chinese Academy of Agricultural Mechanization Sciences, published in Welding Technology (Vol. 25, No. 4, pp. 10–11, 1996), describes the powder feeding surfacing process and its application in manufacturing wear-resistant composite steel plates. Although published nearly three decades ago, the fundamental principles and engineering concepts remain highly relevant to modern surfacing technology.

Powder feeding surfacing (加粉堆焊) is a process variant in which a powdered alloy is fed into the welding arc zone in addition to or in place of a solid electrode, allowing the deposition of wear-resistant or corrosion-resistant overlays with controlled composition and microstructure.

Process Principles

Powder feeding surfacing operates on the principle of arc melting of a continuously fed metal powder, which is introduced into the weld pool through a nozzle system. The process can be configured in several ways:

Configuration	Electrode	Powder Source	Arc Type	Typical Application
Powder-only (no electrode)	None	Side-fed or central-fed	Transferred arc	Thick overlays, high deposition rates
Electrode + powder	Solid rod or wire	Side-fed	Transferred arc	Thin overlays, repair applications
Flux-cored variant	Flux-cored wire	None (powder in core)	Transferred arc	Automated production, consistent results

The key advantages of powder feeding surfacing include:

High deposition efficiency: Powder has a lower specific heat and faster melting rate than solid wire, resulting in higher metal deposition rates (typically 3–5 kg/h versus 1–2 kg/h for solid wire GMAW).
Low cost: Metal powders can be produced from recycled materials or economically from cast alloys, reducing consumable costs.
Composition control: Powder composition can be precisely controlled, allowing optimization of overlay properties independent of the base metal.
Versatility: The process can be adapted to various base materials and overlay compositions.

Wear-Resistant Composite Steel Plate Manufacturing

The paper describes the production of composite steel plates consisting of a structural steel base plate with a wear-resistant surfacing layer deposited on one or both surfaces. The manufacturing process involves:

Base plate preparation: Structural steel plates (typically Q235 or Q345 grade) are prepared with appropriate surface cleaning and preheating.
Substrate welding: If multi-layer construction is required, the base plate is built up to the required thickness.
Powder feeding surfacing: The wear-resistant overlay is deposited using the powder feeding process, with parameters optimized for maximum hardness and minimum dilution.
Post-processing: The composite plate may be stress-relieved and machined to final dimensions.

The resulting composite plate combines the weldability and formability of structural steel with the wear resistance of the overlay, providing a cost-effective alternative to solid wear-resistant steel plates.

Application Characteristics

The wear-resistant composite steel plates produced by this process exhibit the following characteristics:

Property	Structural Steel Base	Wear-Resistant Overlay
Tensile strength	370–520 MPa	500–800 MPa
Hardness	120–180 HV	500–800 HV
Weldability	Good	Limited (hardened)
Formability	Good	Poor
Machinability	Good	Difficult
Abrasion resistance	Low	High

A critical advantage highlighted in the paper is that the composite plates can be cut, formed, drilled, and welded after manufacture, unlike solid wear-resistant steel plates which are often difficult to machine and form. This is because the structural steel base retains its good mechanical properties, while the wear-resistant overlay is confined to the surface.

Process Parameters and Quality Control

Parameter	Typical Value	Quality Impact
Powder feed rate	200–500 g/min	Controls deposition rate and dilution
Arc current	200–400 A	Affects penetration and dilution
Travel speed	0.3–1.5 m/min	Controls bead width and height
Powder-to-wire ratio	1:1 to 3:1	Controls overlay composition
Shielding gas	Ar or Ar+CO₂	Affects arc stability and porosity
Preheat temperature	100–200°C	Reduces cracking susceptibility

Quality control considerations include:

Dilution monitoring: The dilution rate (base metal mixing into the overlay) should be measured periodically to ensure the overlay composition meets specifications.
Porosity inspection: Powder feeding processes are susceptible to porosity if the powder feed is inconsistent or the shielding is inadequate. Visual and radiographic inspection should be performed.
Bond strength testing: The interface between the overlay and base metal should be tested for adhesion, particularly for cyclic loading applications.
Hardness mapping: Cross-sectional hardness profiles should be measured to verify the hardness gradient and confirm adequate overlay thickness.

Engineering Significance and Modern Relevance

Although the paper dates from 1996, the powder feeding surfacing concept has evolved significantly and remains a cornerstone of modern wear-resistant surfacing technology. Modern variants include:

Cold wire transfer (CWT): Where a solid wire is fed through the arc without electrical contact, combining powder feeding with solid wire advantages.
Powder arc surfacing (PAS): Using a plasma or arc to melt pre-mixed powder blends, achieving precise composition control.
Wire-powder hybrid processes: Combining solid wire and powder feeds to optimize deposition rate, cost, and properties.

In the pipeline industry, powder feeding surfacing is used for:

Applying corrosion-resistant overlays to pipeline sections in aggressive environments
Building up worn pipeline components (valves, flanges, scraper assemblies)
Manufacturing composite pipeline components with wear-resistant internal surfaces for slurry service
Repairing pipeline sections with localized wear or erosion damage

The fundamental principle of combining a structural base with a functional surface layer through powder feeding remains an economical and effective strategy for extending the service life of pipeline and equipment components.

Summary

The powder feeding surfacing process described in this paper represents a foundational technology in the wear-resistant surfacing field. Its combination of high deposition efficiency, low cost, and compositional flexibility has made it a workhorse process in industrial manufacturing and repair applications. The concept of composite steel plates — combining structural and functional properties in a single component — continues to be widely applied in pipeline, mining, and agricultural equipment industries. Engineers working with modern surfacing technologies should appreciate the fundamental principles established in this early work, as they form the basis for contemporary powder arc surfacing and hybrid wire-powder processes that are now standard in industrial practice.

Overall Synthesis of the Five Topics

These five studies collectively address the critical aspects of surfacing technology that are directly relevant to pipeline and equipment manufacturing: process parameter optimization (Topics 1 and 4), microstructure-property relationships (Topics 2 and 3), and process-applicability integration (Topic 5). The common thread is that surfacing quality is governed by the interaction between process parameters, consumable chemistry, and thermal-mechanical history. Engineers should adopt a systems perspective that considers all three factors simultaneously when designing and specifying surfacing operations for pipeline and equipment applications. The quantitative models, experimental data, and process guidelines presented in these studies provide a solid technical foundation for making informed engineering decisions in surfacing technology selection and implementation.