Research on Overlay Welding Temperature Field Simulation System Based on ANSYS and VB Integration

Literature Overview

This paper, published in the Journal of Hebei Agricultural University (2008, Vol. 31, No. 3, pp. 105-107), reports the development of a dedicated simulation system for overlay welding temperature field analysis. The system was built on the ANSYS finite element analysis platform and integrated with Visual Basic (VB) programming to create a user-friendly interface. The research was supported by the Hebei Provincial Natural Science Foundation (Project No. E2006000528) and conducted by researchers at the School of Mechanical and Electrical Engineering, Hebei Agricultural University.

The core objective of this work is to bridge the gap between the powerful but complex ANSYS software and the practical needs of welding engineers who require temperature field analysis for overlay welding processes but may lack extensive finite element modeling expertise. By encapsulating the ANSYS workflow within a VB-based graphical interface, the authors created a tool that allows users to input welding parameters directly and obtain temperature field results without navigating the full ANSYS command sequence.

Core Technical Approach

The system architecture follows a client-server pattern where VB serves as the front-end interface and ANSYS acts as the computational engine. The key technical workflow involves several stages:

Model Preprocessing Module

The user inputs geometric parameters of the workpiece (such as plate thickness, diameter for cylindrical substrates, and overlay layer dimensions), material properties (thermal conductivity, specific heat, density, emissivity), and welding parameters (current, voltage, travel speed, heat efficiency factor). The system automatically generates the finite element mesh and assigns boundary conditions.

Thermal Source Modeling

The moving heat source is modeled using either a double-elliptical or Gaussian distribution, depending on the welding process characteristics. The heat input rate Q is calculated from the welding parameters using the relationship Q = η × U × I, where η is the heat efficiency coefficient (typically 0.6-0.85 for arc welding processes), U is the arc voltage, and I is the welding current. The heat source moves along the weld path at the specified travel speed, creating a transient thermal analysis problem.

Result Visualization and Post-Processing

After the ANSYS solver completes the temperature field calculation, the VB interface retrieves the results and presents them through temperature contour maps, time-history temperature curves at critical points, and cooling rate distributions. These outputs are essential for predicting microstructure evolution in the overlay weld, estimating the depth of the heat-affected zone (HAZ), and determining appropriate post-weld heat treatment parameters.

Engineering Significance and Practical Application

For engineers working on overlay welding of critical components such as pump shafts, turbine blades, and pipeline fittings, the ability to rapidly simulate temperature fields is invaluable. The following table summarizes typical parameter ranges that such a system would handle:

In practice, this type of simulation tool enables engineers to perform parametric studies efficiently. For example, when designing an overlay weld for a high-pressure valve body made of austenitic stainless steel, one can systematically vary the travel speed and heat input to find the optimal combination that minimizes dilution while avoiding excessive cooling rates that could lead to cracking in the weld metal.

Study Insights and Critical Reflection

The integration approach demonstrated in this paper represents a pragmatic solution to the software accessibility problem in welding engineering. While modern commercial welding simulation software packages exist, many organizations still rely on general-purpose FEA tools like ANSYS for thermal analysis of welding processes. The VB-based wrapper significantly lowers the learning curve and reduces the risk of user error in setting up complex transient thermal models.

However, several limitations should be noted. The system described focuses solely on thermal analysis and does not couple the temperature field with solidification or phase transformation models. For a complete prediction of overlay weld microstructure and properties, the thermal results would need to be fed into a separate microstructure evolution model or used as input for a thermo-mechanical simulation that accounts for residual stress and distortion.

Furthermore, the accuracy of the simulation depends heavily on the boundary conditions and material property definitions. Overlay welding involves complex heat transfer at the interface between the base metal and the deposited layer, and the heat source model must accurately represent the actual arc characteristics for the specific process being simulated (such as GTAW, GMAW, or SAW). Engineers should validate the simulation results against experimental thermocouple measurements before relying on them for process design decisions.

The fundamental value of this work lies in demonstrating that even relatively simple software integration techniques can dramatically improve the usability of advanced analytical tools. For welding engineers in production environments who need to quickly assess the thermal consequences of parameter changes, such a system provides a practical and efficient means to support decision-making without requiring full-time computational resources.