20 KB330 KB18 KB200020242005Kevorkijan, Varužanletnik:39številka:44 stranistr. 125-128ISSN:1580-2949COBISSID:9789206URN:URN:NBN:SI:doc-Z5CQ494WenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijealuminijaluminumfolijekontinuirno litjemikrostrukturapločevinaMicrostructure and formability development in Al strip casting for thin gauge foil production|The changeover to cast Al strip for foil production has been defined by the management of Impol as the key part of its strategy for the plant's development and the restructuring of roll-casting technology. In comparison with hot-rolled strip, continuous cast strip is a cost-effective raw material for foil production, but different in terms of microstructure, phase composition, formability and other technological characteristics. Due to the very rapid solidification of molten metal in continuous thin strip, the microstructure consists of a strongly supersaturated aluminium solid solution and an increased fraction of fine particles of intermetallic phases, precipitated in Al crystal grains. This has a negative effect on ca st-strip formability, and more over, the cast strip's surface is oxidized and contaminated with graphite. For the purpose of producing strip from technical aluminium (group AAlxxx) and alloys of the Al-Fe type (group AA8xxx) it was necessary to change the casting parameters as well as the parameters for further strip processing, which differ from conventional roll-casting procedures. Continuous cast strip is primarily intended for insulation, converter and household foils of different widths. The principal foil characteristics, prescribed by EN standards, are the mechanical characteristics, surface quality, porosity and the thermostability. The research work was focused on achieving the listed characteristics by changing the alloy composition and the conditions of transformation of continuous cast strip into foil. A sui table thermomechanical treatment changes the distribution of alloy elements in the existing microstructural phases and there by also their effect on static recrystallisation, thereby affecting the surface quality and the mechanical characteristics of the foil. In this study the optimum composition and the process parameters of continuous casting that make it possible to use the strip as raw material for producing sheets and insulation, converter and household foils of standard quality are presentedPrehod na liti Al-trak za proizvodnjo folij je vodstvo Impol-a opredelilo kot ključni del strategije razvoja tovarne in prestrukturiranja valjarništva. Liti trak je v primerjavi s toplo valjanim cenejša surovina za proizvodnjo folij, vendar se od njega razlikuje po mikrostrukturi, fazni sestavi, preoblikovalnosti in drugih tehnoloških lastnostih. Zaradi izjemno hitrega strjevanja taline pri kontinuirnem ulivanju tankih trakov prevladuje v mikrostrukturi močno prenasičena trdna raztopina aluminija s povečanim deležem majhnih zrn intermetalnih faz, ki so dispergirano iz ločene v kristalnih zrnih, kar negativno vpliva na preoblikovalnost litih trakov. Poleg tega je površina litega traku oksidirana in onesnažena z grafitom. Za izdelavo trakov iz tehničnega aluminija (skupina AAlxxx) in zlitin vrste Al-Fe (skupina AA8xxx) je bilo potrebno opredeliti parametre ulivanja in za nadaljnjo predelavo trakov v primerjavi s konvencionalni mi ulivno-valjarniškimi postopki. Kontinuirno uliti trakovi so prednostno namenjeni za izdelavo izolacijskih, konvertorskih in gospodinjskih folij različnih debelin. Glavne lastnosti folij so predpisane z EN-normami, so mehanske lastnosti, kvaliteta površine, poroznost in termostabilnost. Poudarek raziskovalnega dela v okviru projekta je bil doseganje naštetih lastnosti s spreminjanjem zlitinske sestave in pogojev predelave kontinuirno ulitih trakov v folije. Ustrezna termomehanska obdelava spremeni sestavo v mikrostrukturnih fazah in s tem njihov vpliv na statično rekristalizacijo, kar vpliva na kvaliteto površine in mehanske lastnosti folij. V delu smo določili optimalno sestavo in predpisali procesne parametre kontinuiranega ulivanja, pri katerih je liti trak možno uporabiti kot surovino za izdelavo tanke pločevine in izolacijskih, konvertorskih in gospodinjskih folij standardne kakovostiTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije