This thesis is a survey and also an investigation of the different factors that affects the cracking that occurs in the inserts at AB Sandvik Coromants production in Gimo. The work that has been done has focused on two main factors, namely, powder characteristics and pressing parameters.AB Sandvik Coromant produces tools and tooling systems for metal cutting. They have some problems in their production of inserts. The problem is that cracks sometimes occur in the body of the insert, after it´s pressed. In order to investigate this, a preliminary study was made in which production principles were studied. A historical survey has also been made with the help of statistics from the last two years of production. This survey was then followed by a number of experiments in which different factors that possibly had an influence in the cracking was investigated.The work resulted in that one of the pressing parameters was found as a factor whose affect on the cracking is large. The investigation also led to that one of the powder characteristics could be considered as a factor whose affect on the cracking is insignificant. This finding applies to the geometries and powder varieties that were included in the experiments. Otherwise, it was found that further work is required to make any general conclusions.

High quality powder steel is manufactured through gas atomization at Erasteel Kloster AB in Söderfors. During their batches they have a problem with varying weight of capsules which can cause problems with bending capsules and unreliable exchange. Bent capsules risk damaging the equipment and cannot be used.The work was performed with the purpose to investigate the source for varying weights of capsules during batches and with the goal to account for a solution on how the varying capsule weights can be reduced.Powder samples were taken during five batches aiming to investigate the cause for varying capsule weights. The powders characteristics were analyzed with different methods which presented the powders size distribution, fill density, tap density and flowability. The Lubanska equation which calculates powders mean diameter was simplified and adjusted for the Erasteel plant with the intention to control gas pressure depending on the metal flow rate.Analyzes showed that the powder size distribution was changing during every batch. The amount of larger particles decreased more than the amount of small particles increased meanwhile the width of the powders size distribution decreased. This gave the largest width of size distribution half-way into the batch and the highest capsule weights were obtained at this moment.The simplified equation was applied to the moment when highest capsule weights was obtained and gave guidelines on how the gas pressure should be controlled to achieve similar size distribution. Further analyzes showed that the metal flow rate was proportional to the gas temperature due to it is measured after being in contact the melt stream.Since the equation was simplified and verified on five batches more tests needs to be extracted. It needs to be done not only to get a more reliable equation but also for an opportunity to test it in practice. With samples collected from more batches, there is a possibility to control the gas pressure with gas temperature and an automatic control of the gas pressure could be performed. / På Erasteel Kloster AB i Söderfors tillverkas högkvalitativt pulverstål genom gasatomisering. De har ibland under deras körningar problem med varierande kapselvikter vilket kan ge problem med att kapslar veckas vid komprimering samt opålitligt utbyte. Veckade kapslar riskerar att skada komprimeringsutrustningen samtidigt som kapseln måste skrotas. Arbetet utfördes i syftet att undersöka orsaken till varför kapselvikterna varierar under chargerna och med målet att redogöra för hur variationerna på kapselvikterna kan minskas. Under fem körningar togs pulverprover ut för att undersöka orsaken till varför kapselvikterna varierar. Pulvrets egenskaper analyserades med olika metoder vilka gav pulvrets storleksfördelning, fylldensitet, skakdensitet samt flytbarhet. Den Lubanska ekvationen för att beräkna pulvers medeldiameter vid gasatomisering förenklades och anpassades till Erasteels anläggning för att anpassa gastryck efter metallflöde. Analysen visade att pulvrets storleksfördelning förändrades under samtliga körningar. Mängden stora pulverkorn minskade mer än vad mängden små pulverkorn ökade under atomiseringen. Detta medförde att den största variationen av stora och små pulverkorn var halvvägs in i chargen och vid denna tidpunkt erhölls även de högsta kapselvikterna. Den förenklade ekvationen gav, med hjälp av tidpunkten då kapselvikterna var som högst, riktlinjer för hur gastrycket bör styras för att uppnå liknande storleksfördelning. Ytterligare analyser visade att gastemperaturen var proportionellt mot metallflödet, då temperaturen mättes efter att gasen varit i kontakt med det rinnande stålet. Eftersom den tillämpade ekvationen förenklades och verifierades mot endast fem körningar borde fler tester utföras. Detta för att ge en mer tillförlitlig styrning samt möjligheten att testa ekvationens riktlinjer i praktiken. Med provuttag under flera charger finns möjligheten att styra gastryck mot gastemperatur och med hjälp av detta skapa en automatiserad styrning.