Composite auto pour ladles reduce scrap, improve service life.

Many metalcasting operations use auto pour ladles made up of a variety of materials, such as cast iron, steel, cast refractory and fiber laminate. But a new ladle using RFM technology can replace these traditional materials. Pyrotek Inc., Columbia City, Ind., developed the RFM auto pour ladles for use in casting operations.

Pyrotek worked with SPX Contech Corp., Portage, Mich., to replace its fiber laminate ladles with a custom design using RFM technology. Contech uses the ladles as a quality initiative in its squeeze cast operation. The finn found that RFM ladles were light enough to hold the 30-lb. pour weight plus the 14-lb. ladle weight while remaining under the weight rating of its automatic ladler--something it was unable to do with a cast refractory product.

The ladles are constructed from a light-density refractory composite material in a lamination process that produces a thinner base and walls. They also are both tough and tolerant in the face of mild mechanical abuse.

The RFM ladle material is hard-wearing and has better insulating characteristics in comparison to other materials used in this application. With a material density of 1,600 kg [m.sup.3] (100 lbs./[ft.sup.3]), RFM offers exceptional strength-to-density ratio. The ladles also come complete with a factory prepared finish of ZYP boron nitride. This coating offers non-wetting characteristics that enhance the in-use performance of the ladle.

The non-wetting characteristics enable metalcasting facilities to reduce oxide--induced scrap because less foil is generated. An automatic ladler can be programmed to invert the RFM ladle after each pour. allowing any skull that might be present to exit the ladle without the assistance of an air blast. This is possible because of the ladle's non-wetting surface characteristics and because the ladle-mounting bracket is attached to the side of the ladle spout and not extending across the ladle's body where it would block skull release.

If a ladle does not exhibit non-wetting surface characteristics, the skull either forms in the ladle, gradually reducing the ladle volume, or it returns to the clip well. Either way, it contaminates the melt anti future castings with oxides. When the skull returns to the clip well, future castings can be contaminated with oxides that may not be discovered until final inspection. This increases the potential for scrap and can cause tooling damage in machining. Also, when the ladle volume is decreased, the die cannot completely fill, which results in scrap. When the skull is returned to the dip well, it will build up and cause the melt level sensors to prematurely signal that the ladle is at the proper fill level, resulting in an inadequate fill and consequently more scrap due to a short pour.

The RFM ladles are fabricated over a mold, resulting in a consistent shape that produces repeatable pour volume and eliminates the need for an operator to program changes. When ladle shape is inconsistent, reprogramming the ladler fill and pour parameters is required to maintain proper die fill. The mounting hardware is embedded in the RFM ladle and is fixed to the mold during the manufacturing process, which allows for repeatable mounting of the ladle.

With RFM auto pour ladles, a four-month service life with 45,000 shots is not unusual. Intangible benefits with the ladles include reduced maintenance time, reduced oxide-induced scrap and improved repeatability from ladle to ladle.

Select No. 001 at www.moderncasting.com/info