CLADDING TECHNOLOGY SHANXI CO., LTDPowder Addition Welding Process and Wear-Resistant Clad Steel Plate Application
Literature Overview
This 1996 study from the Chinese Academy of Agricultural Mechanization Sciences (CAMAS), authored by Meng Zhaohong, Yan Zhixing, and Wang Shangxian, addresses the powder addition welding (PAW) process applied to the fabrication of wear-resistant clad steel plates for agricultural machinery components. The research was conducted during a period when China's agricultural mechanization sector was rapidly expanding, creating urgent demand for durable, cost-effective wear-resistant components such as plow shares, seed drill discs, and tillage tools. The authors investigated the feasibility of using flux-cored arc welding with external powder addition as a method to deposit hardfacing layers on carbon steel substrates, offering a practical alternative to more expensive processes such as plasma transferred arc welding or electric slag welding.
Core Technical Content
The powder addition welding process described in this work involves a submerged arc welding (SAW) configuration with supplemental alloy powder fed into the arc zone through a dedicated powder feeder. The base material is typically a low-carbon or low-alloy steel plate (e.g., Q235 or Q345), while the wear-resistant overlay is composed of high-carbon, high-chromium martensitic or austenitic compositions. The process parameters investigated include arc voltage, travel speed, wire feed rate, powder feed rate, and shielding flux composition.
| Parameter | Typical Range |
|---|---|
| Arc Voltage | 28–38 V |
| Travel Speed | 250–500 mm/min |
| Wire Diameter | 1.6–2.0 mm |
| Powder Feed Rate | 150–400 g/min |
| Powder-to-Wire Ratio | 1.5–3.0 |
| Preheat Temperature | 100–200 °C (for low-alloy steel) |
| Interpass Temperature | ≤ 250 °C |
The key metallurgical objective is to achieve a dilution ratio between 25% and 45%, ensuring that the overlay retains sufficient hardness (typically 45–55 HRC for martensitic compositions or 35–45 HRC for austenitic compositions) while maintaining adequate toughness at the weld-metal/base-metal interface. The authors emphasize that controlling the powder addition rate is critical: excessive powder leads to high dilution and softening of the overlay, while insufficient powder results in poor coverage and porosity.
Process Analysis and Metallurgical Considerations
The microstructure of the deposited overlay is strongly influenced by the cooling rate, which in turn depends on the travel speed and the number of passes. At higher travel speeds, the cooling rate increases, promoting finer martensitic structures and higher hardness but also increasing the risk of cracking. The authors note that the dilution behavior follows a predictable trend: the first pass exhibits the highest dilution (often 50–60%), while subsequent passes stabilize at lower dilution values (30–40%) as the deposited metal acts as a thermal sink.
A critical finding of this study is the relationship between powder composition and overlay performance. High-carbon high-chromium powders (e.g., Cr15C3 or Cr20C5 type compositions) produce overlays with carbide-rich microstructures consisting of M7C3 and M23C6 carbides dispersed in a martensitic matrix. These carbides provide excellent abrasion resistance against soil and rock particles encountered in agricultural applications. However, the authors caution that excessive carbon content can lead to retained austenite formation, which, while beneficial for impact resistance, may reduce hardness and promote temper embrittlement during service.
The interface between the overlay and the base plate was examined using metallographic techniques. The transition zone typically exhibits a gradient in carbon and chromium concentration, with a narrow region of mixed microstructure spanning approximately 0.1–0.3 mm. This transition zone is critical for bond strength, and the authors recommend maintaining interpass temperatures below 250 °C to avoid excessive grain coarsening and softening in the heat-affected zone (HAZ) of the base plate.
Engineering Practice and Application Implications
The agricultural machinery applications discussed in this paper include plow bodies, disc harrows, and conveyor components. The wear-resistant clad plates fabricated using this process demonstrated a significant improvement in service life compared to unclad carbon steel components. In field trials, the clad plow shares exhibited a service life 3–5 times longer than conventional high-carbon steel counterparts, translating to substantial cost savings in terms of replacement frequency and downtime.
From a manufacturing perspective, the powder addition SAW process offers several advantages over alternative cladding methods:
| Criterion | Powder Addition SAW | Strip Cladding | Laser Cladding |
|---|---|---|---|
| Equipment Cost | Low | Medium | High |
| Deposition Rate | High (2–5 kg/h) | Medium | Low (0.5–1.5 kg/h) |
| Overlay Thickness | 3–8 mm | 2–10 mm | 1–3 mm |
| Geometric Flexibility | High | Limited | High |
| Dilution Control | Moderate | Low dilution | Very low dilution |
| Surface Quality | Good | Excellent | Excellent |
The process is particularly well-suited for large-format plates where deposition rate is a priority, and where the surface finish requirements are moderate (machining can be applied afterward). The authors recommend a two-pass minimum for critical applications to ensure adequate overlay thickness and uniform hardness distribution.
Key Questions and Reflections
Several questions arise from studying this work that remain relevant to contemporary practice. First, the study does not extensively address the hydrogen-induced cracking (HIC) susceptibility of the base plate in the HAZ, which is a concern when using low-hydrogen fluxes with high deposition rates. Second, the long-term durability of the overlay under cyclic loading conditions typical of agricultural implements was not systematically evaluated. Third, the environmental and safety considerations associated with the powder handling and fume generation during the welding process deserve more attention in modern manufacturing contexts.
Despite these limitations, the study provides a solid foundation for understanding the fundamental metallurgy and process control of powder addition welding for wear-resistant applications. The principles of dilution control, interpass temperature management, and microstructure-hardness relationships established in this work remain directly applicable to contemporary powder addition welding practices.
Study Insights and Implications
The most valuable insight from this 1996 study is the demonstration that a relatively simple and economical welding process can produce high-performance wear-resistant clad plates suitable for demanding agricultural applications. The systematic investigation of process parameters and their effects on overlay properties provides a practical framework that can be adapted for other wear-resistant cladding applications. For modern engineers working on bimetal product manufacturing, this study serves as a reminder that process optimization must always balance metallurgical performance with economic feasibility and manufacturing scalability. The powder addition welding approach remains a viable option for large-format wear-resistant cladding where the cost-effectiveness of the process outweighs the slightly higher dilution compared to thermal spray or laser-based methods.