Simple Solutions That Work! Issue 12

16 FIXED Where the cover remains on the treatment ladle throughout the time the ladle is in operation, only being removed at the end of the working shift. The metal is poured into the ladle via the tun-dish box and back out of the tun-dish once the treatment process has taken place. Consequently, the tun-dish is shaped to form a spout and additives are introduced via a separate hatch. TEAPOT SPOUT TREATMENT LADLE The data sheets usually classify teapot sprout ladles as a variation of the fixed tun-dish ladle but most foundry men tend to refer to them as a separate process. The ladle has a fixed cover and the metal is poured into the ladle through a large teapot spout that is throated down as it enters the ladle body at the base. After the treatment the metal is then poured out through the teapot spout. Additives are introduced via a separate hatch in the cover. The fixed tun-dish and the teapot spout treatment ladle have several design similarities; the position of the trunnions must consider the tun- dish with one and the large teapot spout with the other. The design of the additives hatch is often very specific to each foundry, so we always try to make sure that what we offer meets with customer’s requirements. FIXED TUN-DISH AND TEAPOT SPOUT TREATMENT LADLE ADDITIVE HATCH There are two basic types of additives hatch; weighted and locked. The weighted one, as the name implies, relies on the weight of the hatch to keep it closed whereas the locked type has a locking mechanism to keep it shut. Both types of ladles can achieve a good seal and pressure can build up inside the ladle. There seems to be a difference of opinion as to whether this is good or bad. The weighted cover will act as a pressure vent. However, I know that several foundries prefer a locked down cover to maintain the pressure inside the ladle and have said that this gives a better Mg recovery rate. PRE-CAST LINERS The largest impact on ladle design is the increasing use of pre-cast linings, especially in regards to the teapot spout treatment ladle. Acetarc manufacture re-usable lining formers for all our ladle types and to be perfectly honest the lining formers for the teapot spout treatment ladles are a pain to manufacture (it’s the connecting part plus the spout forms that is challenging) and the whole kit is expensive. I understand that the actual lining of the ladle is not easy either. A pre-cast liner gets around these problems. I must admit I don’t know the cost of a pre-cast liner, but I am seeing more foundries make use of them. There a number a design considerations with regards to the ladle. Firstly, it’s easy for us to adjust the shell size to suit an existing pre- cast liner. Secondly, regarding the teapot spout, a significant part of the ladle shell is removed, so we must make sure that the rigidly of the lade shell is maintained. CONCLUSION The best type of in-ladle treatment process may not be the process that on paper gives the best results, but the one that can be best integrated into a foundry’s system. This can be evaluated by evaluating your foundry’s working practices, speaking to your additives supplier and speaking to your ladle supplier. Although sometimes there can be an inclination to use an existing casting ladle, buying a specifically designed treatment ladle is a relatively small capital investment, and it can offer significant advantages. Contact: STEVE HARKER steven.harker@acetarc.co.uk