Abstract
In the simulation of the sand casting process, the numerical calculation of the casting temperature field is the core part. The interfacial heat transfer coefficient (IHTC) is a necessary parameter for accurate calculation of the casting temperature field. This study focuses on the IHTC between the casting and the sand mold/core during the sand casting process.
1. Introduction
1.1 Research Background
Sand casting is widely used due to its low cost, simple production process, short production cycle, and wide application range. The IHTC between the casting and the mold/core significantly affects the temperature field during the solidification process, thereby influencing the final structure and properties of the casting.
Table 1: Comparison of Sand Casting and Metal Mold Casting
| Casting Type | Cost | Production Process | Production Cycle | Application Range |
|---|---|---|---|---|
| Sand Casting | Low | Simple | Short | Wide |
| Metal Mold Casting | High | Complex | Long | Limited |
1.2 Overview of Casting CAE Technology
Casting CAE technology has been actively researched since the 1980s, with numerous research results published. The simulation of the filling process also began to emerge during this period.
1.3 Research Status of Interfacial Heat Transfer Coefficient
Researchers have conducted extensive explorations on factors affecting the IHTC. Early scholars, such as Tillman and Berry, designed experiments to determine the IHTC. Subsequent researchers, like Jacobi, Ho, and Pehlke, further studied the IHTC using different methods and materials.
Table 2: Key Researchers and Their Contributions
| Researcher | Year | Main Contribution |
|---|---|---|
| Tillman and Berry | Early | Designed experiments to determine IHTC using graphite molds |
| Matsubara and Nishida | 1986 | Studied the effect of pressure on IHTC |
| Jacobi | Unknown | Conducted experiments in a vacuum furnace to study IHTC over time |
| Ho and Pehlke | Unknown | Used Beck’s inverse algorithm to study IHTC |
1.4 Main Research Content and Objectives
This study aims to investigate the IHTC between typical ring and plate castings and their corresponding sand molds/cores during solidification. The research contents include designing casting schemes, measuring temperature changes, establishing mathematical models, and verifying the accuracy of the calculated IHTC.
2. Experimental Design for Temperature Measurement
Table 3: Casting and Measurement Details
| Casting Type | Material | Dimensions | Pouring Temperature | Thermocouple Positions |
|---|---|---|---|---|
| Plate Casting | ZL101 | 50mm thick, 150mm×150mm | 705°C | 2mm from casting/mold interface |
| Ring Casting | ZL101 | Inner/Outer Radii: 30/80mm, 50/100mm, 70/120mm; Height: 150mm | 705°C | 2mm from casting/mold interface |
3. Establishment of the Inverse Calculation Program for IHTC
Based on the theory of heat transfer and the characteristics of the inverse heat transfer problem, mathematical models for temperature fields and IHTC were established for plate and ring castings. The models were programmed using MATLAB.
4. Analysis of Calculated IHTC
Table 4: Maximum IHTC Values for Different Casting Radii
| Inner Radius (mm) | Outer Radius (mm) | Maximum IHTC (W/m²·K) for Inner Sand Core | Maximum IHTC (W/m²·K) for Outer Sand Mold |
|---|---|---|---|
| 30 | 80 | 263 | 131 |
| 50 | 100 | 183 | 127 |
| 70 | 120 | 110 | 103 |
The IHTC for the inner sand core was higher than that for the outer sand mold for all ring castings. Additionally, the IHTC decreased as the inner and outer radii increased.
5. Simulation and Verification
The ProCAST simulation software was used to verify the calculated IHTC. The simulated temperature fields were compared with the measured data to assess the accuracy of the calculated IHTC.
Table 5: Simulation Parameters
| Parameter | Description | Value |
|---|---|---|
| Simulation Software | ProCAST | – |
| Geometry Discretization Method | Finite Element Method | – |
| Heat Transfer Models | Energy Equation, Continuity Equation, Momentum Equation | – |
| Boundary Conditions | Interface Heat Transfer, Convection, Radiation | – |
6. Conclusions
This study investigated the IHTC between ZL101 aluminum alloy ring and plate castings and their corresponding sand molds/cores during the sand casting process. The following conclusions were drawn:
- Mathematical models for temperature fields and IHTC were established using the law of conservation of energy and the implicit finite volume method.
- The IHTC was calculated using a MATLAB program and compared with experimental data.
- The IHTC for the inner sand core was higher than that for the outer sand mold and the plate casting.
- The simulated temperature fields using the calculated IHTC were in good agreement with the measured data.
This study provides a reliable method for determining the IHTC in sand casting processes, which can improve the accuracy of casting simulations.