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Metal Casting Technologies : September 2005
The bank manager was such a nice bloke he said he would keep in regular touch to see how things were going. These days we don't hear from the bank manager very much, but regularly somebody from the bank credit department keeps asking when we will be putting money in. Anyhow, with the finances organised, we did the deal and bought ourselves a second hand 'lectric induction furnace. INSTALLATION AND OPERATING THE 'LECTRIC INDUCTION FURNACE The actual furnace itself was small compared to the other paraphernalia which went with it. The coke, limestone and Pig Iron bins had to be cleaned out to make way for the cooling tower unit, and a roof extension was necessary to cover the control unit. When we found out what Kw/Hr meant we got a rude shock after the Electricity Supply Authority advised that a small substation will be necessary to provide enough power to run the thing, and they didn't do that for nothing. Each new day we wondered what else we would find out what we hadn't been told about. It was interesting to calculate that the plumber and the electrician doing the installation were getting a higher hourly rate than we charge for our castings. Anyhow, our 'lectric induction furnace was installed and ready to go to work for us. The old reliable Cupola, looking forlorn, neglected, cobwebbed and forgotten still stood where it had for 45 years, waiting for the executioner to tap it on the shoulder. Old Charlie and Burt (see Figure 5) visited to see the new 'lectric induction furnace expecting to see an electric version of their Cupola. They couldn't understand how something so small that looked like a washing machine, painted green, could replace their big old reliable Cupola. Last seen they gave old reliable an affectionate farewell pat and were observed walking out the gate shaking their heads in bewilderment, like Bib and Bub wandering through fantasy land. FURNACE START UP -- A PAINFUL LEARNING CURVE Everything was done according to advice we received. The induction furnace certainly melts iron quickly, quietly and without much mucking around. HOWEVER, the iron it made was totally different to the stuff the Cupola made. Old Charlie used to say the Cupola iron was so good you could eat it. The induction made iron was giving us all sorts of problems. It was a real headache with hard castings, shrinks and draws the main casting defects occurring. Nothing was consistent except that the furnace was easy to use. Temperature control was a breeze compared to the cupola, where we had to increase the coke splits to get hotter metal. The main factors controlling the Cupola output and metal temperature were the ratio of metal to coke and the quantity of air blast. We battled on. It became obvious later on that induction iron from steel scrap was 'dead' iron. It didn't have the resident nuclei points inherent with the cupola iron trickling through the coke, with reactions creating nuclei points, like Manganese Sulphide etc, and picking up Carbon, Sulphur etc. being the reactions of the intimate contact between the metal and the chemically active coke bed, slag, air and cupola gasses. All the good stuff to make trouble free iron. It became obvious that the induction 'dead' iron would have to be 'doctored' or repaired in some way before it could be used. THE SALES REP FROM FANSCO ARRIVES As we battled on, sometimes chasing our tail, one day a sales rep from 'FANSCO' (Fantastic Foundry Products Supply Company) arrived and said he had products we should buy which were the answer to all our problems. The days of just melting the metal and pouring the moulds were over. The FANSCO rep was here so often Our Boat -- An unnecessary Asset 4 A new 'lectric Induction Furnace 2 Used Induction Furnace 3 Who's Who of Metals 2005/6 75