Successfully designing steel castings. (Steel).

Of the four papers and panels by the Steel Div., two discussed improvements in casting design. In the panel "Software Tools to Aid Casting Design" (02-193), M. Samonds, UES Software, Inc., discussed the advantages of using Finite Element Mesh (FEM) for design. These benefits include:

* clear description of quality;

* detailed treatment of thin-walled sections and complex shapes;

* descriptive treatment of fluid flow;

* a small number of nodes (requiring less memory and disk space);

* stress calculations, including hot tearing, cracking, distortion and thermal fatigue.

With fluid flow in particular, FEM has the capacity to simulate trapped gas, filters and turbulence, according to Samonds. It has several advantages in mold filling and solid analysis because it shows the filling patterns and metal temperature at the end of the fill. It also optimizes the gating design.

S. Kuyucak, CANMET/MTL, presented "A Review of the Feeding Distances in Current Use for Steel Castings" (02-115). The presentation compared feeding rules for steel castings as documented by the Steel Founders' Society of America (SFSA) and compared them to recent work based on solidification simulation and Niyama's criterion.

Kuyucak explained that feeding rules for steel castings have been summarized in terms of the number of thicknesses that can be fed (NFD') vs. plate thickness and width-to-thickness ratio (W'). The old SFSA rules show a decreasing NFD' with increasing thickness, whereas the new rules show no such variation with thickness. Differences in W' values indicate that the old rules lead to conservative values in wide plates. For greater confidence in feeding rules, these differences must be reconciled, Kuyucak summarized.

In other presentations in the division, topics included heat treatment research and filtration troubleshooting.