Simple Solutions That Work! Issue 12

12 However, this information approaches the subject from a mostly academic angle, concentrating on aspects such as: • Commercial advantages and disadvantages of the various processes • Best magnesium recovery rate • Optimum treatment process for particular mixes of alloys and choice of size of particles etc. All of which are obviously important. The design of the actual type of treatment ladle to be used also tends to follow this academic approach, listing what features a type of treatment ladle should have for the best results but they seldom look at the ladle design from a practical point of view—how these STEVE HARKER Technical Director ACETARC ENGINEERING CO. Ltd ARTICLE TAKEAWAYS: • Open Top, Teapot, Tun-dish advantages and disadvantages • All about Loose & Sliding Tun-dish Ladles • Benefits of Freeboard and detachable bases BACK TO BASICS: DUCTILE IRON TREATMENT LADLES features can be achieved and what impact they have on the overall ladle design. It is this aspect that I’d like to explore. Acetarc have been manufacturing treatment ladles, of all types, for decades and the following is based on my experience, and a mixture of what I’ve seen in foundries and the feedback received. It has been a long and evolving process and, over the years, we’ve adapted our ladle designs to make them better suited to their purpose. As always, feedback from the foundries has been critical in the ongoing design development. It’s not my position to say which process or choice of additives are the best, as there are others better qualified to give an opinion on this, T he in-ladle production of ductile (nodular) iron uses a number of long established processes and there is much information available on the subject. but I think I can point out some ladle features that might help a foundry to have a better treatment ladle. The best in-ladle treatment process is the one that works best for each foundry. If you are happy with it then it works for you. I’m going to cover the following treatment ladle designs; open top, for the over-pour or sandwich process, (Acetarc calls ‘deep treatment’) and the various tun-dish treatment ladles including the teapot spout type. These ladles often have different names but hopefully you will understand which type of ladle I’m discussing. The open top ladle is a good place to start as the main design features will also be found, to some extent, on the other types of treatment ladle. OPEN TOP/OVER POUR (SANDWICH) DEEP TREATMENT LADLE This ladle doesn’t have a cover. There is a pocket in the base that is charged with additives and a covering, usually a metal stamping but sometimes a thin cast plate is placed over the top. The metal is poured into the ladle and the covering is intended to delay the reaction long enough for the ladle to be filled with enough metal to fully cover the additives. It is the most basic type of treatment ladle and the least efficient but, possibly due to the ease of use is still popular. You will usually see it stated that the ladle should have a shell with a height to diameter ratio of 2:1 or greater. I’ve even seen articles that even suggest 3:1. While this is true from improving the treatment process efficiency,