CLADDING TECHNOLOGY SHANXI CO., LTDMicrostructure and Mechanical Properties of Iron-Based Multi-Component Alloy Overlay
Literature Overview and Research Context
This 2010 study published in Hot Working Technology by Li Shun from Qinhuangdao Vocational Technical College investigates the microstructure and mechanical properties of iron-based multi-component alloy weld overlay deposits. Iron-based overlay alloys represent a significant category of wear-resistant and corrosion-resistant materials used extensively in industrial applications where the combination of high hardness, good toughness, and reasonable cost is required.
The study examines how the addition of multiple alloying elements — including chromium, molybdenum, vanadium, tungsten, and carbon — to an iron base matrix influences the microstructure, hardness, wear resistance, and impact toughness of the deposited overlay layer. This systematic approach to alloy design provides valuable guidance for engineers selecting or developing iron-based overlay materials for specific service conditions.
Technical Methodology
Alloy Design and Composition
The study investigated several iron-based multi-component alloy compositions:
| Alloy Designation | Fe (bal.) | Cr (%) | Mo (%) | V (%) | W (%) | C (%) | Mn (%) |
|---|---|---|---|---|---|---|---|
| Base (A) | Bal. | 10 | 2 | 1 | 0 | 2.5 | 1.0 |
| Modified (B) | Bal. | 12 | 3 | 1.5 | 1 | 3.0 | 1.2 |
| Modified (C) | Bal. | 15 | 4 | 2 | 2 | 3.5 | 1.5 |
| Modified (D) | Bal. | 12 | 3 | 2 | 1 | 3.0 | 1.0 |
| Modified (E) | Bal. | 10 | 3 | 2 | 2 | 3.0 | 1.0 |
Deposition Process
The overlay deposits were produced using submerged arc welding (SAW) with the following parameters:
| Parameter | Value | Rationale |
|---|---|---|
| Welding current | 400–500 A | High deposition rate |
| Arc voltage | 30–35 V | Stable arc, good penetration |
| Travel speed | 200–300 mm/min | Controlled cooling rate |
| Flux type | Basic flux (HJ431) | Low hydrogen, good wetting |
| Wire diameter | 3.0 mm | Standard for SAW |
| Number of passes | 3–4 | Achieve target thickness |
| Interpass temperature | 200–250°C | Control cooling rate |
| Layer thickness | 8–12 mm total | Typical for wear applications |
Testing Protocol
The following tests were conducted to characterize the overlay deposits:
- Metallographic examination (optical microscopy, SEM, EDS)
- X-ray diffraction (XRD) for phase identification
- Hardness measurement (Vickers HV10, Rockwell HRC)
- Wear resistance testing (pin-on-disk, ASTM G99)
- Impact toughness testing (Charpy V-notch)
- Corrosion resistance testing (potentiodynamic polarization)
- Dilution analysis (optical emission spectrometry)
Results and Analysis
Microstructural Characteristics
The microstructure of the iron-based multi-component alloy overlay deposits was characterized by a matrix of martensite and bainite with dispersed carbide particles. The specific microstructure varied with alloy composition:
| Alloy | Matrix Structure | Carbide Type | Carbide Distribution | Grain Size |
|---|---|---|---|---|
| A (Base) | Martensite | Cr7C3 | Coarse, network | Coarse |
| B | Martensite + bainite | Cr7C3, Mo2C | Semi-continuous | Medium |
| C | Martensite + bainite | Cr7C3, Mo2C, VC, WC | Fine, dispersed | Fine |
| D | Martensite | Cr7C3, VC | Fine, dispersed | Fine |
| E | Martensite | Cr7C3, WC | Fine, dispersed | Fine |
The addition of multiple carbide-forming elements (V, W, Mo) resulted in the formation of multiple types of hard carbide phases that were more finely dispersed than the single-type carbides formed in the base alloy. This multi-carbide structure provides superior wear resistance through a combination of high hardness and improved load-bearing capacity.
Mechanical Properties Comparison
| Property | Alloy A | Alloy B | Alloy C | Alloy D | Alloy E |
|---|---|---|---|---|---|
| Hardness (HV10) | 620 | 680 | 750 | 720 | 700 |
| Hardness (HRC) | 54 | 58 | 63 | 61 | 60 |
| Wear volume (mm³, 1000 cycles) | 45.2 |