This is a report on my thesis work on bachelor level that took place on SSAB Oxelösund during the spring of 2018. The work has revolved around concept development of an installation for hardness measuring in their production line, and has furthered the development of an existing project. During the last years, different aspects of the project have been analyzed to bring the project closer to a realization.The work has focused around taking a closer look on a concept of a unit meant to perform surface preparation, indentations and topographical analysis of steel plate. The goal is to install this in a so called in-line solution, using a portal over the production line as a basis. This has involved function analysis, establishing target specifications and suggest existing components that can fit those. To define the demands for the target specifications, tests have been performed on vibration factors on the suggested installation place, and laser as a means to clean steel surfaces have been tried out.The result have been an advancement on earlier concepts. Suggestions have been made regarding components, sub functions have been further defined, environmental factors have been analyzed and new technology for surface preparation have been successfully tried out.

In this work four fiber-reinforced polymers and one polymer were tested with four different mechanical testing methods, namely; vickers harness test, scratch test, fatigue test and tensile stress. The testing methods were evaluated according to their applicability on the materials mentioned. The purpose of the work is to give the reader an insight of what mechanical properties of materials mean and what kinds of properties one can expect from fiber-reinforced polymers. The purpose is also to give the reader a good sense of what can be expected from the methods tested on fiber-reinforced polymers. Vickers harness test was found to be a valid method as long as the surface of the material was neither uneven nor processed. Scratch test was found to be an overall good method but was recommended to be used in combination with scanning electron microscope, or other imaging tool for strong magnification. Processing of surfaces proved to affect the results. Tensile test was proved to give the user a good perception of the properties of the material, as long as the material not was woven. Woven materials found to differ a lot from each other. One conclusion from this result is that woven materials are best to be tested several times. Fatigue test was found to require more preparatory time and calculations to be able to give the user any useful results, the loads used in the project was found to be too light weight. Processed surfaces were found to be hard to examine in a scanning electron microscope.

Rapporten baseras på en litteratur- och intervjustudie kring underhållsstrategier och komponentutbyten i kärnkraftverk, med fokus på komponenter som tenderar till att påverkas av åldring i en högre grad. Exemplifiering sker genom en kompletterande fallstudie kring kabel- och rörgenomföringar av typen Brattbergare som har packbitar bestående av ett polymert material. Erhållet resultat av litteratur- och intervjustudien belyser vilka säkerhetsföreskrifter som råder för all kärnteknisk verksamhet i Sverige. Utöver det erhålls information om hur åldring påverkar ett materials egenskaper över tid och att detta ligger till grund för fastställandet av ett system eller en komponents kvalificerade livslängd. I takt med att majoriteten av världens kärnkraftverk närmar sig sin ursprungligt tilltänkta livslängd och planeras underhållas för fortsatt långtidsdrift finns det ett ökat intresse för effektiva underhållsstrategier. Åldershanteringen har en avgörande roll för anläggningens lönsamhet och driftsäkerhet. Fallstudien föreslår två olika underhållsstrategier som stöds av resultatet av litteratur- och intervjustudien. Deras ekologiska påverkan och ekonomiska omfattning beaktas för att utse den metod som har störst potential att öka resurseffektiviteten och minska kostnaderna för underhållsåtgärder. Vald metod går ut på att praktiska tillståndsmätningar tillämpas för att undersöka hårdheten av packbitar till Brattbergare. Hårdhetsmätningarna syftar till att ge indikationer på i vilken grad packbitarna harpåverkats av degraderande åldringsmekanismer under olika förutsättningar. Resultatet av fallstudien överensstämmer med de resultat som noterades i litteratur- och intervjustudien. Packbitarna hårdnar när de åldras. Två miljöbetingelser som tenderar till att påskynda åldringsprocessen är förhöjda temperaturer och stråldoser. Vald metod för fallstudien är praktiskt realiserbar trots vissa begränsningar i befintliga kärnkraftsanläggningar vid Forsmark. Presenterad strategi bör kunna bistå med en ekologisk och ekonomisk optimering av underhållsarbetet för kabel- och rörgenomföringar. / This report is based on a literature study and interviews regarding maintenance strategies and component replacements in nuclear power plants. Focuses of the study are on components which tend to more commonly be affected by degrading aging mechanisms. Exemplification is done with a complementary case study about cable- and pipe transits with packing pieces made of polymeric materials. A frequently used application for cable- and pipe transits in Swedish NPPs is manufactured by MCT Brattberg AB.  Result obtained from interviews with relevant personnel’s and the literature study providing knowledge about prevailing safety regulations at Swedish nuclear facilities. Moreover, information is gained about how aging affects the features of materials over time and that it is the basis for determining the qualified lifetime of systems and components. Further on this could be of specific interest considering that the majority of the worlds NPPs are close to its intended lifetime and soon entering a phase of LTO. A proper aging management is an important factor when it comes to a safe and reliable operation of an NPP.  The case study compares two different maintenance strategies which are supported by the obtained result from interviews and the literature study. Considering ecological and economic impacts of the strategies, the one with the greatest potential to reduce negative influences are exemplified. Chosen method included practical hardness measurement with a portable durometer at packing pieces for cable- and pipe transits. Measured hardness of the packing pieces indicates at what degree which they have been affected by degrading aging mechanisms given different circumstances.   The obtained result from the two different parts of the report is corresponding to each other. Packing pieces consisting polymers hardens as they age. Elevated temperatures and higher dose rates accelerates the aging process. Represented method of the case study is practically viable at existing NPPs at Forsmark. Presented strategy should be able to assist with an ecological and economic optimization maintenance work for cable- and pipe transits.

I detta examensarbete har undersökningar kring finfrästa ytor i härdat verktygsstål utförts i samarbete med verktygsstålsproducenten Uddeholms AB i Hagfors. Vid spånskärande bearbetning påverkas materialet ibland negativt. En försöksserie om totalt 90 finfrästa ytor i härdade varmarbetsstålen Uddeholm Orvar Supreme och Uddeholm Dievar har frästs, mätts och utvärderats för att ta reda på hur fräsprocessen inverkar på materialets egenskaper. Det visar sig att materialet påverkas olika mycket beroende på hur fräsningen utförs och med vilken typ av fräsverktyg som används. I detta arbete har endast ändradiefräsar av solid hårdmetall använts. Analysen av ytorna har gjorts med en rad mätmetoder så som optisk ytjämnhetsmätning, hårdhetsmätning med Vickersmetoden, restspänningsmätning med röntgendiffraktion och okulär inspektion av stålets mikrostruktur i ljusmikroskop. Mätningarna utfördes för att se hur materialet påverkas mekaniskt av bearbetningen.   I de mest ogynnsamma försöksfallen är den mekaniska påverkan från fräsbearbetningen av stålets ytor så stor att bearbetningen riskerar försämra tillverkade komponenters livslängd sett ur utmattningssynpunkt. Målet med arbetet är att identifiera det mest gynnsamma sätt fräsningen kan utföras på för att kunna minimera påverkan på materialets egenskaper. Detta ger möjligheten för Uddeholms AB att ge faktabaserade råd till sina kunder om vilket körsätt som ger minsta påverkan av verktygsstålet vid bearbetning. Kunderna kan nyttja då materialet till dess fulla kapacitet. / In this thesis, investigations on hardened finish milled surfaces was done in collaboration with the tool steel manufacturer Uddeholms AB in Hagfors, Sweden. The steel material is affected by machining operations, sometimes in a negative destructive manner. An experimental test series containing a total of 90 surfaces in hot work steels Uddeholm Orvar Supreme and Uddeholm Dievar were milled, measured and evaluated to clarify the milling operations effect on the steels mechanical properties. It was found that the material is affected differently according to how the milling was preformed and with which type of milling tool. In this thesis, only solid carbide end-radius milling tools were used. The surface analysis were conducted with a range of measuring techniques including optical surface roughness measurements, hardness measurements in Vickers scale, residual stress measurements with X-ray diffraction (XRD) and microstructural analysis with optical light microscope. These measurements were conducted in order to determine the milling operations mechanical affects and grade of alteration of the tool steels surfaces. In the least favorable cases, the effect from machining are so profound, that degradation of produced components can be expected in terms of fatigue wear resistance. The goal of the thesis is to identify the most favorable process parameters, in order to minimize degradation of the tooling material in customer user cases, together with the opportunity to give fact based advice to Uddeholms AB customers on the most favorable process parameters in finish milling with radius-mills of hardened hot work tool steels. In this way the customer can utilize the tooling material at its full potential.