LADLE-NOZZLE OPENING AND GENETIC PROGRAMMING

ODPIRANJE IZLIVKA PONVE S PODŽIGANJEM IN GENETSKO PROGRAMIRANJE

Miha Kovačič1,2, Beno Jurjovec1, Luka Krajnc1

1Štore Steel, d. o. o., Železarska cesta 3, 3220 Štore, Slovenia
2University of Nova Gorica, Laboratory for Multiphase Processes, Vipavska 13, 5000 Nova Gorica, Slovenia

miha.kovacic@store-steel.si

Prejem rokopisa – received: 2013-01-08; sprejem za objavo – accepted for publication: 2013-04-25

 

Štore Steel Ltd. faces a huge problem with the ladle nozzle opening during the production of a wide variety of steel grades. After a ladle treatment the steel melt is poured from the ladle through the sliding gate and the nozzle into the tundish on the continuous casting machine. Due to frequent clogging the ladle nozzle must be opened with oxygen which can cause melt pollution. The purpose of this paper is to present an attempt to reduce ladle-nozzle openings. In this attempt the genetic-programming method was used. The experimental data on 115 consecutively cast heats was used. The steelmaking-technology number, the batch sequence number, the time spend for secondary metallurgy, the sustainability of the upper-nozzle brick, the sustainability of the nozzle seating block, the sustainability of the lower-nozzle brick, the ladle number, the sustainability of the ladle and of the foreman of secondary metallurgy and the melt chemical composition (Al, C, Mn and Si) were taken into account for the prediction of the ladle-nozzle opening. The best genetically developed model for the ladle-nozzle-opening prediction correctly predicts 107 out of 115 situations of opening the ladle. The results of the genetic-programming-based modeling have been used in practice to change several steelmaking technologies.

Keywords: secondary metallurgy, ladle-nozzle opening, modeling, genetic programming

 

Štore Steel, d. o. o., se spopada s težavo podžiganja izlivka ponve pri izdelavi ogromnega števila različnih kvalitet jekla. Po obdelavi na ponovčni peči se taline skozi drsno zapiralo in izlivek prelije v vmesno ponovco na kontinuirni livni napravi. Zaradi pogostega mašenja se izlivki odpirajo s kisikovim kopjem, kar lahko povzroča onesnaženje taline. Namen študije je bil zmanjšati število podžiganj. Uporabljena je bila metoda genetskega programiranja. Pri napovedovanju podžiganja smo upoštevali številko tehnološkega postopka izdelave jekla, zaporedno številko šarže pri sekvenci, čas sekundarne metalurgije, vzdržnost zunanjega izlivka ter ponovce, ponovčarja in kemično sestavo taline (Al, C, Mn in Si). Najboljši genetsko dobljeni model je napovedal 107 od 115 dejansko izvršenih podžiganj. Rezultati modeliranja z genetskim programiranjem so privedli do sprememb več tehnologij izdelave jekla.

Ključne besede: sekundarna metalurgija, podžiganje, modeliranje, genetsko programiranje

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