The excavator casting part known as the bucket tooth experiences extreme wear during excavation operations. To optimize performance, bimetallic composite casting combines high-chromium white iron (tip) with low-alloy steel (shank). The transition zone between these metals critically determines structural integrity. This study employs hydraulic simulation to analyze fluid interactions during sequential pouring, revealing key parameters controlling interface quality in excavator casting part production.
Experimental Methodology
Using a 1:1 acrylic mold replicating actual excavator casting part geometry, we simulated molten metal flow with viscosity-adjusted fluids. “Cast iron” phase analogs included:
| Simulation Fluid | Viscosity (mPa·s) | Real-World Equivalent |
|---|---|---|
| Water | 1.0 | Short interval pouring |
| 20% PAM solution | 3.0 | Medium interval |
| 50% PAM solution | 5.0 | Long interval |
Dye-enhanced water represented “steel” with viscosity fixed at 1.0 mPa·s. Pouring sequences followed the equation governing momentum transfer:
$$Re = \frac{\rho v L}{\mu}$$
where \(Re\) = Reynolds number, \(\rho\) = density, \(v\) = velocity, \(L\) = characteristic length, and \(\mu\) = dynamic viscosity. Flow patterns were recorded at two initial fill heights (Hhigh = 70mm, Hlow = 40mm) for each viscosity case.
Quantitative Analysis of Transition Zone Formation
Mixing depth (Md) directly correlates with transition zone width in actual excavator casting part production. Experimental measurements revealed:
| Iron Viscosity (mPa·s) | Fill Height | Mixing Depth (mm) | Flow Pattern |
|---|---|---|---|
| 1.0 | High | 60 | Clockwise |
| 1.0 | Low | 120 | Counter-clockwise |
| 3.0 | High | 50 | Clockwise |
| 3.0 | Low | 80 | Counter-clockwise |
| 5.0 | High | 40 | Clockwise |
| 5.0 | Low | 60 | Counter-clockwise |
The inverse relationship between viscosity and mixing follows the diffusion equation:
$$\frac{\partial C}{\partial t} = D\nabla^2 C – v\nabla C$$
where \(C\) = concentration, \(D\) = diffusion coefficient, and \(v\) = velocity vector. Higher viscosity reduces \(D\), narrowing the mixing zone in the excavator casting part.
Operational Guidelines for Excavator Casting Part Production
For optimal transition zone integrity in bimetallic excavator casting parts:
- Maintain initial fill height ≥70% of tip cavity depth to minimize velocity vectors perpendicular to the interface
- Control pouring intervals using the viscosity-temperature relationship:
$$\mu = \mu_0 e^{E/R(1/T-1/T_0)}$$
where \(E\) = activation energy, \(R\) = gas constant, \(T\) = temperature - Optimize interval time (t) to balance interface width and slag removal:
$$t_{opt} = \frac{k \cdot \Delta T^{1.5}}{\mu_0^{0.7}}$$
where \(k\) = mold constant, \(\Delta T\) = superheat
These parameters ensure metallurgical bonding while maintaining efficient production of high-performance excavator casting parts.