Hi I've been looking through the website on and off for last month, reading various posts on issues relating to crucibles applications and their performances, and thought I could be of help if anyone had any specific questions or needed to pointed in right direction on crucibles performance, application or problem solving. My background is foundry for last 40 + yrs. Working last 27 yrs for Morgan in business development, sales, technical support through Asia+Pacific, and up to recently as last 3 months held position as Global Applications role for Morgan Crucible (Morgan Molten Metal System). I've travelled extensively through Americas, Asia and parts of Europe, so seen a fair few furnaces, coal, gas, electric and induction, so they are all a little different. I'm happy to help where I can, however still working in full time position so don't pound me expecting answer within 5min Merry Xmas
Welcome bjf. Always a pleasure to have input from the pros. From a very satisifed Morgan customer..... Best, Kelly
bjf, Thanks for joining the forum and offering your considerable expertise. I melt iron in an A25 Super Salamander using diesel as my energy source. I use a typical atomizer nozzle and forced combustion air. I seem to get around twenty 90 to 100 minute melts per crucible. Is there a better crucible choice? Any tips on how to extend service of the crucible? Mine seem to thin mostly in an area from the level of molten metal to the rim with the lower portion of the crucible deteriorating significantly slower than the upper 2-3 inches. I generally melt about 60 to 65 pounds at a time as I find pouring a rim-full crucible a "hit and miss" proposition. Denis
Probably that the lower part which is immersed in the metal is protected against attack by slag. That is the reason using too much borax or other slag is detrimental for the crucible. And a rim-full crucible is an extra risk that the user spills over when moving the full crucible from the furnace to the mold.
melterskelter: excuse delay, need to turn on the push infor. button as didn't get notification of your question. can you advise how you heat the crucible up, or prepare it for melting, is the crucible preheated to required temp, and then you charge cast iron or steel and carbon/silicon to convert to iron ?. If you could post a few pic of the crucible showing top rim would be good so we are looking at the same issues, as sometimes we interpret different issues. a pic explains more If the charge is cast iron, then metal should be relatively clean, are you adding nay flux to clean, as shouldn't need it are you filling the crucible to 80% plus or running < 50% of the volume cheers Brett
Brett, No worries. I appreciate you taking the time. It's not a problem that has to be answered today though I was melting iron today finishing just before the hailstorm hit. I melt ductile iron returns but do not use magnesium to make ductile iron. The returns are very clean---bright and shiny. I simply cast the melt as grey iron. I use no flux. The brim-full capacity should be 75 pounds of iron but I typically melt 60 to 65 pounds. To begin a melt I pack the crucible with as much iron as I can get into it---usually about 34 pounds and up to 40 pounds (rarely). The crucible is then placed in my diesel-fired furnace and I start the fire running .19L/min and as hot as I can adjust the flame as guessed by appearance and experience. I think there is just a tad more fuel than the air can burn---a slightly reducing flame. After about 45 mins to 50 mins I add the rest of the charge to get to 60 to 65 pounds. A melt takes about 90 to 100 mins. I do add an ounce or so of FeSi a min or two prior to pouring. I do add some crushed charcoal and oyster shell to the empty crucible prior to the melt to ensure maximum carbon and to reduce sulfur in the iron. My iron is nice and uniformly soft with no tendency to form white iron. Here is a photo of a crucible that was pushed a long way---likely 25 melts. You can see the rim is disappearing. And you can also see about 3 inches below the rim a sort of "water mark" where the top of the iron pool usually rests. Below that level the crucible retains near full thickness but then tapers to thin at the rim above that level. As a side note, the crucible looks like it might be ready to collapse but I have never seen a hint of deformation as the wall thickness is well maintained from 3" down to the base. Your thoughts? Denis
Indeed, this picture shows clearly that the immersed part of the crucible is barely deteriorated, unlike above that. You add 1 ounce (31g) of FeSi to 65 pounds (30kg) cast iron ? That is 1:1000 which is a negligible amount. Is that correct ? Why not adding Magnesium ?
Correct ratio of FeSi as stated. Do not want or need ductile for the application if these castings. Denis
