Boring 1) First Borings 35â„…, Second pig iron 10%, Third MS 20% and last RR 35%. Borings are from our own machine shop. Melt rate, I can not say (as we have excess Melting capacity) 2) I have to check. These are our own machined shop Borings. They are well maintained 3) Dust maximum, we have to decide. As per procedure here: Fines passing though 70 mesh should not be more than 2%. These fines also, they check with magnet. Take 100 grams samples, pass it through 70 no mesh. 4) Here as per practice, not more than 1% 5) Further enquired: Bought out Borings Fines ( minus 70 mesh less than 5% ( in this non magnetic particles maximum 1%) 6) 1 mm sieve analysis & collect the fine impurities .it should not more than 5%.Collected fine impurities put in furnace & check for slag formation. But in any case impurities less than 5%.Other condition rusty, oily or no foreign particles. 7) Better arrive at slag formation by weighing of slag... 8) Only "in-house "boring "should be used. Bought out if used, should be of ROUGH CUT and from a known source. 9) How much maximum % boring is getting used for induction melting? How much heel metal to be kept? What is exact end to end cost benefit? If we use boring till it's coolant get vaporize, we can't increase power due to high flames. Melt rate decreases & power consumption gets increase .Also melting loss is high up to 8 to 10% for boring. Please give comments. 10) 80 %is also used. Please do not think of economics. 11) We have to introduce bare minimum standards of acceptance...We can't have anything and discuss of safety n economy.... 12) Did you not get the email of the results with 10% and 20% boring used in furnace shared by Sandeep Kulkarniji y'day night? Please go through, it is recent practical study by him 13) If quality of boring is good, you can add maximum to achieve your base metal requirement of Si%, 85 to 90% also can be. 13) Ignoring power consumption.... 14) Best way is weighing of slag for the sample in a given batch and deduct for the excess losses ....@ material+ power + productivity
15) yes doing this action as well as recording kw shall help anyone % use of boring and turning. pl see the balance on saving of material cost and extra power 16) Impurities in Boring Fines Oil Grinding powder Sand 17) Dr Prasad Rao and Mr Soley, A genuine machinability problem and no adverse results in spectrometer caused by bought out borings can only be explained by trace elements. Carbide forming elements like Cr, Mo, V etc can not be missed in spectrometer, other trace elements are to be considered. There is large amount of literature on effect of trace elements on micro and properties of grey iron. Boron more than 0.05%, Bismuth more tha n0.035%,Lead in smallest traces and Ti ore than 0.2% produce D E type flakes.Boron and Bismuth have been traced from use of enameled scrap and Ti from Pig iron. 18) Pb promots Widmanstatten.... 19) ✔✔Excellent. And one point to add for those who use bought out boring. Spectro shows everything as usual. Mc shop all of a sudden complains poor mcbility. Foundry gropes in the dark. Any takers for this?: (1) Bought out Borings are not uniform. Varying chemistry. Spectrometer is not calibrated for trace elements like Mo W,V etc at lower % levels. People can not afford to have standards for these elements. So spectrometer can not capture these. (2) Borings can replace RR, but not pig iron. 20) Widmansteten in the beginning and undercooled graphite too on increasing quantity 21) Undercooled graphite as a result of denucleation in normal circumstances. .unless alloys are traced.... 22) Induction melting denucleats the melt with every melt cycle... Spectral analysis backed up with cooling curve plotting is the best combination....wedge test a must.... 23) weight analysis to be done though it is length y process 24) detection of alloy element 25) It is not possible to analyse trace elements by wet analysis 26) Dr Rao For shop floor issues like machinability Vs bought out CI boring need a shop floor observations What all we can say generic Ex boring may be rusty Dry or wet borings Any mix up with Sg or MS To some extent Telemedicine is okay Beyond that patient to be seen Krk
27) Yes Mr Rao, Boring can replace RR but not pig iron surely. Also as rightly said spectro can show limited treace elements. Most important is in.consistency & non uniformity of boring which causes variations. 28) There fore good foundries take borings from known sources, never from market. Not only because of trace elements but excess melting loss due to oil, dirt and knowingly addition of mill scale etc