Document DDDdD297YDrmzRMM6qQJDxDxa

-^7HOT TOP TESTING PROCEDURES N. D. Wilcox September, 1975 7' tds The following information may be old hat to some, elementary to oibers. But, in this competitive age, to get a competitive edge, proper care must be exercised. Therefore, at the risk of boring you, here it is. In any test, it behooves the people or person involved to maximize the con ditions to insure the best possible results. Hot Top testing is no different. It is especially important in these days of heavy price competition that we attempt to offer to the customer, results that competition cannot duplicate, making a higher priced system cost efficient or more valuable in use than competitive price leaders. BY RESULTS, I AM SPEAKING OF THREE BASIC ELEMENTS: 1. Better yield 2. Better segregation characteristics 3. Improved reliability HOW DO WE OFFER RESULTS THAT COMPETITION CANNOT DUPLICATE? 1. Be designing a top that contains the least feasible volume at the maxi mum ingot weight. 2. By designing reliability features such * as a tapered top. 3. By insuring that our PROFAX/PROFLEX recipe and quality of that recipe are the f best available.* 4. By making sure the manufacture of the ^Tt^**^**^**"* system is to print. . 5. By insuring that the best possible topping f<*+ compound is used at the right time and in right quantity. **" THERE ARE FOUR BASIC STAGES THAT MUST BE FOLLOWED CLOSELY IN TESTING, pft*co<.v 1 * ortutex 4 X. Setting Z J2T. Pouring 2250 Holding PLAINTIFFS continued Hot Top Testing Procedures N. D. Wilcox September, 1975 Page 2 of 5 1. SETTING 4. Charging 5. Rolling (m* CwtfVf Big End Down A. Make sure the boards fit properly. If the boards are held away from the mold due to bad top manufacture, scrap on the mold wall or any other reason, molten metal will penetrate behind the boards and cause a boiling reaction which, in turn, causes bad surface and board entrapment in the hot top area. In many cases the board breaks away, causing a floater. If the mold is corrugated, check the fit extra carefully to insure that the corrugations of the sideboard match those of die mold. B. To help maximize the setting,- proper hardware should be designed with consideration to type and size of the mold. The hardware used must be applied at the proper place, which in most cases, is approx imately 1/3 of the way from the bottom of the board. Boards that are not fastened tightly and/or at the wrong location will also tend to float. Bear in mind that a floater, in most cases, means the ingot involved will either be diverted (downgraded) or scrapped, making it necessary to re-melt, which is very costly. C. In the case of variable settings, (setting the board at various heights in the mold to vary ingot weight), make sure that the boards are set at the desired height for the particular heat. Most mills measure down from the top. Some have devices that measure from the bottom and mark the mold with chalk. D. After setting, make note of anytime the tops are exposed to rain or any kind of water. Wet or damp boards will boil. Re-check the boards after the molds have been transferred to the pouring area to make sure that the movement did not shake anything loose. Big End Up A. The Big End Up hot top casting is nothing more than a mold extention to hold the insert and ring. Care should be taken to see that the tops are set properly, fit is good and material is manufactured to specifi. cations. 2251 continued Hot Top Testing Procedures N. D. Wilcox September, 1975 Page 3 of 5 B. Inspect the mold tops prior to setting the castings on the molds. Vv* /* Scrap on top of, or a defective mold top (cracked, chipped, etc.) can cause the metal to leak. The ingot will then be diverted or // scrapped. . W C. When placing the castings on the molds, make sure the rings are not damaged by impact with the mold. If any axe, have the crane man return the casting to the stand and replace the ring. Check to see that the castings are centered properly. An off center casting will cause a leak between the ring and mold. Again, the ingot will be diverted or scrapped. It also necessitates cleaning the scrap off the top of the mold before it can be poured again. D. As in the case of Big End Down, check the hot tops after they have been transferred to the pouring area to make sure no damage was incurred in movement. Again, wet or damp boards will boil so make note of any exposure to water. (2. >fUr 2. POURING A. The procedures are much the same in both B. E. U. and B. E. D. The observing party should be familiar with the recommended pouring height (how high up on the boards the metal is poured) and make sure the steel pourer is accurate. B. The compound should be up on the platform prior to pouring. Check before the heat is tapped and if compound is not there, inform the Pit Foreman so he can get it to you. Check the compound contain ers and make sure the bag weights are right. C. The compound should be applied! immediately after the mold is filled. This insures the maximum results. If the helper is lax in application time, tell him that you are conducting a test and you would appreciate his help. D. Make note of any irregularities with attention to type, ingot number (in sequence of pour) and if serious enough, the steel pourer's name. E. Use the attached test data sheet to note heat number, grade, etc. to insure that you will follow the same heat throughout. rnfl h**t T** lHtfT T*P (X^r**-**. THfty 2252 Hot Top Testing Procedures N. D. Wilcox September, 1975 Page 4 of 5 3. HOLDING A. The basic purpose of holding ingots at the pouring platform for a prescribed time is to allow proper solidification and to allow segregation to top out as far up in the ingot as possible. Some mills pull the drag from the pouring platform immediately after pouring to a sidetrack for holding. If the drag must be moved, it should be immediately after the heat is poured. B. Holding time can be computed by the following formula: 1/2 the narrow cross section squared (in minutes) For example, 30 x 45 mold 15 2 / io 15 x 15 * 225 minutes This is approximate and indicates to you whether the mill is fol lowing established procedures. An early pull can foul up your test by changing the segregation characteristics, mainly by placing them lower in the ingot, reducing the yield 4. CHARGING ^ C^ A. When the ingot is taken from the mold, obviously the temperature is super hot to hot going from center to surface. The purpose of the soaking pit is to bring the temperature of the ingot to a uniform level throughout. This temperature normally is in the area of 2400 degree F. At 2400 degrees the steel is in a plastic state and will roll without cracking. B. As the ingots of the heat are charged into the soaking pit, you must confer with the foreman in charge and get the positions of the ingots in the pit. The positions are either alphabetical or numerical. This is important so that you can identify your test ingots as they are pulled from the soaking pit and rolled. Make sure you have the telephone numbers for the soaking pit and rolling mill foremen's offices. Most times, they forget to call you to observe the rolling so check with them frequently when the rolling time nears, generally eight to twelve hours from charge, depending on ingot size. 2253 continued Hot Top Testing Procedures N. D. Wilcox September, 1975 Page 5 of 5 5. ROLLING A. Every effort should be made to properly identify each ingot as it is removed from the soaking pit and rolled. Some tests involve one or more additional suppliers as well as control ingots poured with stan*dard practice. B. Utilizing the attached form, record the following information: 1. Ingot number and/or letter 2. Hot topping system used on each ingot. 3. Heat number 4. Slab, billet, bloom or round size being rolled 5. Top crop (in inches) 6. Bottom crop (in inches) 7. Length of each finished slab, billet, bloom or round 8. Recorded rolling mill yield (or a computation of cubic inches X 0.28 lbs. and matching it against the theoretical gross ingot weight. ^(UvMt ft'*" Do not hesitate to ask questions nor to nicely question the practices if they appear to be working against you. Many shearmen will cooperate fully if you tell them what you want. Remember that your future in the particular mill may be at stake and riding on the test. Treat it critically. -fc 225** FOSECQ-MINSEP. INC. ROLLING MILL DATA SHEET (^ATE: ___________________ MILL: ___________________ HEAT NO: ___________________ MOLD SIZE: ______________ B. E. U._____________ B. E. D. THEORETICAL GROSS INGOT WEIGHT: CHEMISTRY: INGOT HOT TOP PRODUCT TOP BOTTOM LENGTH I. D. USED SIZE ROLLED CROP (") CROP O FINISHED YIELD COMMENTS PRODUCT i 1 : - i f, 2255