| Summary: | The gating system transfers the iron melt from the ladle to the void in the casting mould. The gating systems dimensions and designs are crucial for the success of a casting and a poor gating system is a leading cause of scraps. The main goal of this thesis is to improve the pouring basins and sprues at Norrlandsgjuteriet, an iron foundry located in northern Sweden. The step in the offset step basin and other variables that affect the gating system is explained, investigated and simulated in MAGMASOFT. Furthermore, put to practice at Norrlandsgjuteriet. Adding a step in the offset basin fills a very important function in the system, fending off air bubbles that might enter the mould and reduce the horizontal velocity of the melt. The basin’s height and the sprue’s cross-section control the casting time and simulations conducted in this thesis show that a step can create a beneficial rounding to the flow over the step, creating a laminar flow of the melt, down the sprue contributing to a lower casting time. A narrower sprue is better, in which the melt’s surface tension is maintained, creating an oxide pipe-layer that protects the flowing melt entering the mould and from entrainment defects. The results show that replacing the offset basins used today with offset step basins, which are 30% smaller in volume, together with a tighter sprue will not only reduce the annual material consumption by 1% or 13 000 kg but more importantly increase the quality of the casting. This due to lower melt velocity, a more homogenous temperature, better flow in the basin with less air entering the mould. Ingjutsystemet transporterar det smälta järnet från skänken till gjutformens hålrum. Ingjutsystemets dimensioner och utformning är avgörande för en lyckad gjutning och ett dåligt utformat ingjutsystem är den främsta orsaken till kassationer. Syftet med denna rapport är att förbättra gjutskålarna samt nedlopp som Norrlandsgjuteriet, ett järngjuteri i norra Sverige, använder. Steget i den förskjutna gjutskålen och andra variabler ...
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