Casting simulation
The use of numerical simulation during the casting of valve parts provides essential information that cannot otherwise be seen .
By Samuel Venel Simulation Engineer at Inoxyda
Numerical casting simulation technology provides information about physical and thermal phenomena that we cannot see in the actual casting process . The technology provides information on the filling and solidification phases and the heat exchanges that occur during the cooling . Inoxyda has been casting large-size aluminium bronze alloy pump and valve components using simulation for over twenty years to guarantee quality .
Main interest
The foundry simulation helps us to understand the material behaviour during every phase of the casting process , from the start of the pouring until the solidification and final cooling of the part . Its ’ use is a major asset in particular to :
• Improve quality
• Optimise production process
• Reduce manufacturing costs
• Predict significant defects
• Conduct experimental plans
Using simulation , we are able to visualise the proper filling of the part and avoid risks such as soundness , blister , pitting , air traps or sand defects . It also enables us to check the proper solidification of the part in order to avoid risks of shrinkage , hot spots , porosity , and mixed solidification , all of which lead to poor casting quality . Casting simulation helps us to monitor the manufacturing process from casting to cooling , including solidification .
Figure 1 . DN 2800 Disc - 5720 kg ‘ as cast ’ weight .
Figure 2 . Stand-alone thermal map of 108 ’’ disc .
Getting started
The simulation is based on the following three steps . Thermal evaluation : The first step is to make a thermal evaluation of the original part design without any feeder or cooling system . The aim is to visualise any possible solidification problems to target the areas that will need special attention to reach high-quality standards . During pre-processing , we set up the geometry and define and generate a mesh of the part , the material properties and the heat exchanges .
Calculation by iteration
The calculation is an iteration process , including several steps to reach an optimal mould design . This step includes the design and calculation of a proper feeding system and also a suitable cooling system . To do so , we use the results of the thermal evaluation to design and place the riser in areas poorly fed with alloy .
Figure 3 . 108 ” disc with feeding system .
We also design the cooling system to guide the solidification front towards the riser . Figure 3 shows the part with a proper feeding system . The result of the simulation will highlight porosity areas , as shown in Figure 4 , which highlights that at least one additional iteration will be necessary to reach the required quality level .
Final analysis and results
Simulating the mould filling phase will allow us to visualise different results such as :
• The temperature during filling , filling time , filling velocity ,
• The fraction solid / fraction liquid , π www . valve-world . net Valve World November 2022
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