February 2024 Volume 6

MATERIALS

The New Practical Method for Flow Visualization The starting point for the new practical flow visualization method is to take a series of workpieces, such as the 100Cr6 (Ovako grade 803) sample shown in Figure 5. Then a series of holes are drilled right through the samples, from top to bottom. Into these holes are inserted closely-fitting rods manufactured from a lower grade of steel, such as C9D. Because there is a clear visual contrast between the two steel grades, these rods act as very effective “markers” for indicating how the material has flowed. The next step is to subject the samples with the marker rods inserted to each of the hot-working process stages. At various points the process is halted, so that the sample can be removed for examination in the laboratory. The patterns that emerge after sectioning, polishing and etching make it possible to build a clear picture of the material flow at each stage.

Figure 3: 3D model of billet with rods introduced before upsetting.

Figure 5: Inserting metal rods into holes drilled in a sample billet provides a practical approach to flow visualization. The Upsetting Stage In Figure 6 we can see that the behavior of the inserted metal rods in the FORGE simulation compares well with the practical test.

Figure 4: From top to bottom, the upsetting, piercing and ring rolling setup in the FORGE software.

Figure 6: Sample after upsetting showing the material flow of the rods from the practical industrial trial (top row) and from the FORGE simulation (bottom row).

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