Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 12 uppsatser.

Lic.-avh. Luleå : Luleå tekniska univ., 2008.

Diss. (sammanfattning) Uppsala : Univ., 2007. / Härtill 9 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2008. / Härtill 7 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2005. / Härtill 7 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 7 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 11 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2007. / Härtill 6 uppsatser.

I pappersmaskiner används kräppblad för att kräppa av pappret från en stor roterande cylinder, en så kallad yankee-cylinder. Dessa blad utstår stora nötningar och beläggs därför med antingen en kromoxidbeläggning eller en hårdmetallsbeläggning för att öka bladets nötningsbeständighet. Bladen beläggs med termisk sprutning, kromoxiden via plasmasprutning och hårdmetallen via "High-Velocity-Oxy-Fuel"-sprutning (HVOF). I detta arbete har slitagetester utförts på belagda kräppblad genom att använda en "slider-on-flat-surface" (SOFS) tribometer för att ta reda på vilken av dessa beläggningar som är bäst lämpad för att användas på kräppblad. Vid användning av SOFS belastas kräppbladen med en normalkraft och glider mot en platta till önskad total glidsträcka är uppnådd. För att kunna genomföra slitagetesterna i SOFSen behövdes en fixtur konstrueras och tillverkas och kräppblad behövde kapas till önskad geometri. Det skapades tre koncept för fixturen och med en beslutsmatris gjordes valet vilken av dem som skulle tillverkas. Den tillverkade fixturen håller kräppbladen stabila i både sidled och i glidriktningen och håller kräppbladen i en vinkel likt i verkligheten. Slitagetesterna utfördes vid tre olika glidsträckor med konstant normallast. Efter slitagetesterna analyserades bladen i stereomikroskop och svepelektronmikroskop för att identifiera nötningsmekanismer. De dominerande nötningsmekanismerna var abrasiv och adhesiv nötning. På grund av porositet i beläggningarna ökades antalet sprickor och mer och mer fragment lossnade vid ökande glidsträcka under slitagetesterna. Det visade sig efter mätningar av bortnött bredd på bladet att det hårdmetallbelagda kräppbladet hade bäst nötningsbeständighet. Detta på grund av dess hårda tungstenkarbider som minskade den abrasiva nötningen och spricktillväxten i beläggningen och dess högre duktilitet jämfört med kromoxiden. / Creping blades are used in paper machines for creping tissue paper from a rotating cylinder called a yankee cylinder. These blades experience severe wear and are therefore coated by either chromium oxide or a hard metal coating to make the blades more wear resistant. The coatings are sprayed on to the blade by thermal spraying processes, the chromium oxide coating with plasma spraying and the hard metal coating with "High-Velocity-Oxy-Fuel" (HVOF) spraying. In this thesis wear testing of the coated creping blade using a "slider-on-flat-surface" (SOFS) tribometer has been done to find out which of these coatings that is best suited for coating on the creping blade. When using the SOFS, the creping blade is subjected to a chosen normal force and is scraped against a counterface for a set total distance. In order to execute the wear tests in SOFS, construction and manufacturing of a holder for the creping blades was needed and the creping blades had to be cut to correct geometry. Three concepts were created for the holder and the decicion about which one to manufacture was made with a decision matrix. The new holder holds the creping blades stable in side movements and in the sliding direction. It also keeps the blade at a set angle to the counterface as in the real application. The wear tests consisted of three sliding distances with constant normal load. The blades were analyzed in a stereo microscope and in a scanning electron microscope to identify the wear mechanisms when the wear tests were completed. The major wear mechanisms were abrasive and adhesive wear. Because of porosity in the coatings, the number of cracks increased and fragments from the blades came loose when increasing the sliding distance during the wear tests. It showed that by measuring the eroded width on the blades that the hard metal coated blade had the best wear resistance because of the hard tungsten carbides that lowered the abrasive wear and the crack growth in the coating and because of its higher ductility in comparison to chromium oxide.

Cone crushers are widely used in the mining, mineral processing and quarrying segments of the industry to crush ores and large rocks. In such machinery, the load to be carried is rather heavy and the motion is gyratory which creates a need for a bearing set that can withstand such severe conditions. Sandvik AB is a high-technology Swedish engineering group specialized in tools and tooling systems for metal cutting, equipment, as well as tools and services for the mining and construction industries. One of their products relevant to the mining industry is the cone crusher which utilizes a 3-piece bearing set to carry thrust load. This bearing can be classified as a Spiral Groove Bearing \footnote{The abbreviation S.G.B will be used interchangeably throughout the thesis.}, and it has been incurred that it wears out rather quickly and is believed to be running under mixed-lubrication conditions where the interfaces in the bearing-set are not fully lubricated. The aim behind this thesis is to create a multiphysics model of this bearing in order to understand deeply how it works and the reasons why it does not perform as expected as well as to predict design improvements which can improve the performance of the bearing-set, thus increasing its operating life. It has been concluded that the bearing operates under severe mixed-lubrication conditions and that the generation of a squeeze film is the only method by which lubrication takes place due to the excessive depth of the grooves which is needed to allow for an adequate amount of cold oil to flow into the grooves and cool the interface as well as to accommodate for a considerable amount of wear particles. In light of the results and insight gathered from the simulations, possible design variations of the bearing which can be advantageous in terms of mitigating asperity friction in the interfaces of the bearing are discussed and tested.