This procedure applies to the operations of two 5000 lb. capacity furnaces with one 1250 kw variable frequency power unit to melt steel.

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1 PAGE: 1 of SCOPE This procedure applies to the operations of two 5000 lb. capacity furnaces with one 1250 kw variable frequency power unit to melt steel. 2.0 RESPONSIBILITY The melter is responsible for operating these furnaces, for producing and delivering liquid metal having specified final chemistry and pouring temperature as per manufacturing instruction for the castings. To fulfill this responsibility he/she must be thoroughly conversant with this operating procedure, as well as other documents listed under References. 3.0 CHARGE MATERIAL 3.1 Charging Material and Method The charge material for induction furnaces consists of the following: Purchased scrap Foundry returns Borings and turnings Ferro Alloys Carbon raisers, etc Use only dry, clean material, free from oil, grease, heavy rust and excessive amounts of sand Caution: Do not use charge material with water, ice, snow, oil or grease which may explode in the furnace, injuring people or damaging equipment Do not use sealed containers, tubes, gearboxes, etc. which may also explode in the furnace Do not use heavily rusted steel, when charged into liquid steel it may start a vigorous carbon boil which can be unsafe, depleting carbon,

2 PAGE: 2 of 10 silicon, manganese, etc. from the bath and cause excessive erosion of the furnace lining Dirty and oxidized materials produce excessive amounts of slag, which is difficult to handle and bad for the lining. 3.2 Preparation of Charge Material The maximum size of charge material is limited by crucible size and should not exceed 24 inches in any dimension. Charge material longer than 24 inches in only one dimension may be used with caution, if it is guided into the crucible during melting Do not let large pieces jam up the crucible, which may damage the furnace Break or cut all large pieces to the above limit Clean heavy adhering sand, dirt and rust from all gates and scraps by shot blasting, screening or shaking 3.3 Storage Purchased scrap and pig iron will be stored outdoors Steel turnings and foundry returns are to be stored indoors or under cover Alloys are to be stored indoors, near the furnace. 3.4 Identification of Charge Materials All materials to be charged in the furnace or added to the ladle must be recognizable by their source, name and chemistry All purchased scrap, Ferro-alloys, etc. are to be identified by their trade name and chemistry All foundry returns are to be tagged, identifying MSF material grade. 3.5 Charge Makeup

3 PAGE: 3 of Determine the furnace holding capacity. The crucible is designed for 5000 lbs. holding capacity, however, the capacity varies due to slag build up or erosion of the lining. 3.6 Drying and Pre-Heating 4.0 CHARGING Assure that charge materials are dry Wet material and materials with snow and ice should be brought indoors to dry out If needed, use a heating torch to dry and preheat the scraps Wet scrap may be used in an empty furnace, before the metal starts to melt Never use wet materials in the furnace with liquid metal in it. 4.1 Fill an empty furnace with clean charge materials. Axles, structural steel, plate scraps, steel wheels, foundry returns, machine shop turnings, etc. are ideal materials. 4.2 Keep filling as the metal starts melting. 4.3 If back charge consists of large pieces, use them when the previous charge is only partially melted. 4.4 Small dry pieces can be back charged in liquid bath. 4.5 Use chain or sling to charge large pieces and bucket or shovel for small pieces. 4.6 Do not drop heavy pieces from a height into the furnace. 5.0 MELTING 5.1 The melting unit consists of two 5000 lb. capacity crucible furnaces equipped with one 1250 kw power source. 5.2 Maximum melting rate of this furnace is 5000 lbs. of steel an hour. However, actual melting rate depends on the amount and duration of power used.

4 PAGE: 4 of After melt down, it take approximately minutes for a heat to slag off, take tests, control chemistry, adjust tapping temperature and tap the furnace. 5.4 If only one furnace is used, melting power can not be used during this time and consequently melting rate will be lower, approximately 3000 lbs. per hour. 5.5 To optimize production: Use both furnaces Minimize interruption on use of power. Use of power in one furnace while charging, slagging, sampling or tapping the other Use full power Prepare charge ahead of time and recharge furnace after tap without any delay Minimize analysis and correction time Reduce slagging time by regular use of flux, slag coagulant, etc. 5.6 Assuming heat loss of 130 kw per hour, per furnace and using both the furnaces the following melting rate is expected: Applied Power kw Minutes per Heat (5000 lbs.) No. of Heats per 8 Hours Melt down the charge following the charge make up instructions and the charging sequence outlined in Section 4.7 above. 5.8 As metal melts down, keep filling the furnace until the whole heat is melted. 5.9 Skim off slag using slag coagulant.

5 PAGE: 5 of Caution 6.0 COLD START Do not let the metal bridge the furnace or liquid slag freeze up on top. In either case, liquid metal below the frozen top will overheat and start melting the lining. Loss of lining can be dangerous In case of metal bridging, tilt the furnace so that liquid metal comes in contact with the solid bridge and gradually melt down the solid To prevent too much slag build up, use clean scrap and do not allow too much oxidation of the melt. Solid slag is easy to remove. If the slag is liquid and is more than one inch thick, either remove it by running it off or keep it liquid In case of frozen slag, make a whole and use flux through this hole to liquefy and remove slag. 6.1 A cold crucible after a shutdown normally cracks. The cracks will heal when the crucible is heated up. 6.2 In order to ensure that all cracks in the crucible are closed, the lining should be heated up slowly, at 400 F to above 1200 F before melting starts. If melting starts too early, before the cracks are healed, liquid metal may enter the cracks and will cause electrical short. 6.3 Use the following instructions for a cold start: 7.0 HOT START Fill the furnaces with dense charge, at least 1000 lbs. in each furnace Apply 500 kw of power, alternately for 10 minutes between furnaces. That is to say 10 minutes power on and 10 minutes power off to each furnace, for two to three hours At this time the lining should heat up and the cracks will heal Apply full power and start melting.

6 PAGE: 6 of Once the furnace lining is hot, full power can be applied to the charge and melt down can proceed immediately. 7.2 It is a good practice to keep the furnace lining hot during off shift hours. It not only prevents a cold start, but also increases furnace lining life. 8.0 HOLDING PROCEDURE 8.1 The furnace lining should be kept hot throughout the week. This should be done by keeping metal hot in the furnace, in solid state, during off shift hours, using holding power. 8.2 Holding Solid Charge at 1500 F to 2000 F After tapping the furnace, immediately charge back Apply power at the rate of 200 kw per ton of charge in the furnace to heat up, but do not melt Apply holding power at the rate of 130 kw per hour per furnace. 8.3 Holding Liquid Metal Liquid steel is very corrosive to the lining. The melt should be tapped as soon as possible. However, depending on the production requirement, liquid metal may be held in the furnace for a prolonged period In order to prevent carbon loss in the melt and excessive erosion of the lining, having carbon between 0.2% and 0.4%, hold carbon steel at a temperature between 2800 F and 2850 F. 9.0 SLAGGING AND SKIMMING METAL IN THE FURNACE 9.1 An excessive amount of slag is formed in the furnace due to: Dirty scrap and too much sand in the charge Too much rust or scale in charge material. etc.) Too low a temperature of the bath (oxidation of iron, manganese, silicon,

7 PAGE: 7 of Too high a temperature of the bath (Thermo-chemical reaction and melting of lining material) 9.2 All attempts should be made to prevent excessive slag formation. 9.3 Use slag coagulant to collect powdery, lumpy and liquid slag and remove the slag with skimmer. 9.4 If the slag is too thick, gummy and difficult to handle, increase the temperature of the bath to 3000 F and use flux to liquefy the slag. 9.5 At no time should the furnace temperature exceed 3200 F. 9.6 If the furnace temperature exceeds 3200 F, immediately shut off power. Add clean, dry foundry returns to cool down the liquid steel. Tap the metal as soon as possible. 9.7 Switch off furnace power at all times while slagging or sampling TESTING AND MELT QUALITY 10.1 Carbon Steel After melting down the charge, thoroughly slag off and take chemical test samples (QAI Chemical Analysis). Get test results by using ABS soft ware Raise metal to aim temperature as per the Heat Build-Up Card. The metal should start sparking at this time Skim the slag off using slag coagulant Add Ferro-silicon and Ferro-manganese in the furnace and thoroughly mix up Add other alloys as required Allow the ingredients to dissolve Thoroughly clean the metal surface

8 PAGE: 8 of Check the chemical analysis, if the chemistry is acceptable. If not, adjust chemistry (special grades) Superheat the metal according to aim ladle temperature as set out in Heat Build-Up Card, proceed to tap Tap the metal immediately into a preheated ladle Add specific amounts of de-oxidizers (Al) in the ladle, while tapping Take temperature and record on the Electric Furnace Log Sheet. (Form QAF ) The metal is now ready for pouring As soon as the metal is tapped, re-charge the furnace, put power on and start melting the next heat POURING 11.1 The metal should be poured quickly after skimming and recording temperature Heat loss is open top, preheated 2500 lb. and 5000lb ladles is estimated to be 20º F and 10º F per minute, respectively Pouring should be completed within 5 to 10 minutes after tapping Pour each mold as fast as possible Increase pouring speed immediately after pouring starts and keep the pouring cup full Slowly taper off near the end of a pour Too slow pouring will cause casting defects, resulting in either rejection or excessive repair and upgrading cost.

9 PAGE: 9 of FURNACE SHUT DOWN PROCEDURE 12.1 Thoroughly slag off the last heat before shut down and empty the furnace completely Turn off the melting and holding power, but keep the control power on to maintain supervision on the cooling system Allow the crucible to cool down completely with the cover either closed or open, but without any assistance from fan or water spray Use a chisel to separate the lining from the spout refractory before cooling down the crucible to prevent hang up of the lining, which may cause large horizontal cracks in the crucible The coil cooling water must continue to flow until the crucible lining is cooled down to 145 F or less INSPECTION OF LINING 13.1 The lining must be inspected visually after every heat and measured as required, for erosion and cracks The fail safe method is a plumb bob hung along the crucible axis and the distance (radius) to the crucible wall is measured to at least 4 points on the circumference at successive levels, 6 inches apart. See QAI Induction Furnace Lining Measurement Crucible contraction during cool down causes cracks up to 1/8 wide depending on the size of the crucible. Such cracks are expected to close up again during the following heat up of the crucible to 2000 F. Hence, such cracks should not be patched with any plastic material Larger cracks normally reach all the way back to the felt lining and are not expected to close. The furnace must be relined Measurement of the crucible radius is entered in a log sheet with date. The original reading of the new crucible prior to sintering (measuring from the center towards ramming form) is compared with following log sheets.

10 PAGE: 10 of 13.6 Based on comparison, life expectancy of the crucible may be predictable under normal use The furnace must be relined if the wear of the wall and bottom lining exceed 25% of the original dimensions An average reduction of the wall thickness by 25% will increase the kw input by approximately 15% to 25%. Such increases of power absorption may actuate the over-current protection and shut off the furnace. By no means should the furnace operation be continued at reduced power Hazards Fire, Heat, Sparks, Chemicals, Hot Molten Steel, Trip and Fall, Pinch Points, Struck By, Caught Between, Noise 15.0 PPE Helmet, Safety Glasses, Dark Shield, Safety Boots, Hearing Protection, Fire Retardant Clothing 16.0 REFERENCES 16.1 FORMS QAF Electric Furnace Log Sheet 16.2 PROCEDURES QAP Melting and Pouring 16.3 INSTRUCTIONS QAI Chemical Analysis QAI Lining Measurement, Induction Furnace QAI Sintering of Lining, Induction Furnace QAI Emergency and Safety, Induction Furnace QAI Daily Lining Maintenance, Induction Furnace