Pèfòmans nan TundishCastables REFRACTORYse dirèkteman gen rapò ak Harmony nan pwodiksyon depoze kontinyèl ak bon jan kalite a nan lengote. Kòm yon paramèt pwosesis kle anvan itilize nan Tundish a, tanperati a boulanjri jwe yon wòl desizif nan chanjman sa yo fizik ak chimik, estabilite estriktirèl ak lavi sèvis nan materyèl yo REFRACTORY. Diferan kalite materyèl REFRACTORY gen diferans enpòtan nan repons yo nan tanperati a pandan pwosesis la boulanjri. Kontwòl rezonab nan tanperati a boulanjri se avantou debaz la pou pèfòmans nan Castables materyèl REFRACTORY. Sa ki annapre yo pral kòmanse ak materyèl tipik REFRACTORY tankou materyèl sèk mayezyòm ak penti espre mayezyòm nan sistematik analize efè yo kle nan tanperati boulanjri sou pèfòmans nan materyèl REFRACTORY Tundish.
1. Efè tanperati a sou mayezyòm sèk refractory castables tundish materyèl REFRACTORY
1. Etap tanperati ki ba (<200℃): water release and structural stress control The main change of magnesium dry materials in the low temperature baking stage (usually <200℃) is the release of free water and crystal water. If the heating rate is too fast (such as more than 10℃/min), the rapid evaporation of water will form a pressure gradient inside the material, leading to microcracks or even macro cracks. Studies have shown that when the baking temperature is increased at a rate of 5-8℃/min in the range of 100-150℃, moisture can be evenly removed to avoid stress concentration. A steel plant once had a transverse crack in the working lining of magnesium dry material due to excessively fast heating (15℃/min) in the low temperature stage. The crack width reached 3mm and the length was 400-1200mm, which seriously affected the service life of the tundish. In addition, insufficient insulation time in the low temperature stage will cause residual moisture. The residual moisture will evaporate when the subsequent molten steel is poured, and may invade the molten steel to form pores, while weakening the bonding strength of the refractory material. Experimental data show that after 2 hours of insulation at 150℃, the flexural strength of the dry material can reach 7.87MPa, while the strength of the sample that was not fully insulated is only 5.2MPa, a decrease of 34%.
2. Etap tanperati mwayen (200-800 degre): transfòmasyon lyan ak fluctuation fòs mayezyòm sèk refractory castables souvan itilize résine kòm yon lyan, epi yo pral sibi pwosesis la kle nan geri résine ak dekonpozisyon nan seri a nan 200-600 degre . 200-400 degre: résine a kòmanse pou solidifye epi fòme yon twa-dimansyon rezo, pou antre nan rezo a. Nan tan sa a, si tanperati a pa rete lontan ase ak résine a pa konplètman solidifye, fòs la nan materyèl la sèk nan zòn nan tanperati mwayen yo pral siyifikativman redwi. Eksperyans yo montre ke apre 1 èdtan nan izolasyon nan 400 degre, fòs la konpresiv nan materyèl la sèk ka rive jwenn 7.9MPA, pandan y ap fòs la nan echantiyon an uninsulé se sèlman 4.1MPA.400-800 degre: résine a piti piti dekonpoze ak degaje gaz tankou CO ak CO₂, sa ki lakòz estrikti a entèn nan materyèl yo dwe tanporè ak fòs yo ak ". Lè tanperati a rive nan 800 degre, si tan an izolasyon se ensifizan (tankou<2 hours), the gas produced by the decomposition of the residual resin may form pores inside the refractory material, reducing the corrosion resistance. A steel plant optimized the medium temperature stage process (600℃ insulation for 3 hours) to stabilize the medium temperature strength of the dry material at 6.5-7.2MPa, an increase of 30% compared with before optimization.
3. High temperature stage (>800 degre): sinterizasyon densifikasyon ak fòmasyon segondè fòs tanperati segondè boulanjri tanperati (800-1200 degre) se etap nan kle pou sinterizasyon densifikasyon nan materyèl sèk mayezyòm. Nan seri sa a tanperati, patikil yo mayezi rkristalize, ak limit yo grenn jaden plon yo fòme yon estrikti dans, ki siyifikativman amelyore fòs la tanperati ki wo ak rezistans ewozyon nan castables yo REFRACTORY. Etid yo montre ke lè tanperati a boulanjri leve nan 1100 degre epi li se kenbe cho pou 4 èdtan, fòs la konpresiv nan materyèl la sèk ka rive jwenn 11.33MPA, ki se 57% pi wo pase sa yo ki nan etap nan tanperati mwayen, ak endèks la rezistans ewozyon salop ogmante de 1.8 a 2.5. Si tanperati a nan etap nan tanperati ki wo se ensifizan (tankou<1000℃) or the insulation time is short (<3 hours), the refractory material is not fully sintered, the internal porosity increases, and the erosion resistance decreases. After a steel plant increased the high temperature baking temperature from 900℃ to 1100℃, the erosion rate of the tundish working lining dropped from 5mm/furnace to 3mm/furnace, and the number of continuous casting furnaces was extended from 10 furnaces to more than 15 furnaces.
2. Efè tanperati boulanjri sou Castables REFRACTORY nan kouch espre mayezyòm
1. Efè tanperati a sou kouch lyezon fòs: se kouch espre mayezyòm flite, ak tanperati boulanjri li yo dirèkteman afekte fòs la lyezon ant kouch la ak kouch la pèmanan. Si tanperati a leve twò vit nan etap nan tanperati ki ba (<150℃), the water in the coating evaporates quickly, which will cause hollowing and peeling of the coating; the medium temperature stage (300-600℃) is the key period for dehydration of cement binder hydration products, and improper temperature control will weaken the bonding strength between the coatings. A steel plant adopts a staged heating process (150℃ insulation for 2 hours → 400℃ insulation for 3 hours → 800℃ insulation for 2 hours), so that the bonding strength between the spray coating and the permanent layer reaches 1.2MPa, which is 40% higher than the original process.
2. Efè segondè tanperati sinterizasyon sou rezistans ewozyon
Segondè tanperati boulanjri (800-1000 degre) nan kouch espre mayezyòm ka ankouraje fòmasyon nan mayezyòm-aliminyòm faz spinèl ak amelyore rezistans salop. Lè tanperati a boulanjri rive nan 1000 degre epi li se kenbe cho pou 3 èdtan, endèks la rezistans ewozyon salop nan kouch nan espre ogmante soti nan 1.5 a 2.2, ki se 47% pi wo pase sa yo ki an kouch a ki pa konplètman sinterize. Si tanperati a wo se ensifizan (tankou <900 degre), kristal yo periclase nan kouch nan espre yo pa konplètman devlope, epi li se rezistans a ewozyon siyifikativman redwi. Yon plant asye yon fwa te lakòz kouch nan espre ki pasyèlman kale koupe lè depoze gwo founo dife a 5th.
