Among emerging materials systems for thermoelectric applications, the early transition-metal nitrides based on ScN and CrN show unexpectedly promising properties. These properties are determined by high Seebeck coefficient, low thermal conductivity, and high electrical conductivity. There is, however, still a need to improve the thermoelectric properties. One idea is to introduce dopants or alloying elements to alter the concentration, mobility, and/or type of charge carriers, such as in (Cr1-xVx)N. Another is to focus on the different scattering mechanisms, such as to reduce the scattering of electrons and increase the scattering of phonons, thus increasing the electrical conductivity while lowering the thermal conductivity. Electrical conductivity can be altered by grain boundary modifications, such as larger grains as well as metallic inclusions, for a smoother interface for the electrons. Such nanoinclusions could potentially also act as phonon scattering centra. Phonon scattering can also occur by site substitution of isoelectronic but heavier atoms, which could reduce the phonon mean free path while retaining the electrical conductivity. For CrN, the obvious substitutions are Mo or W.This thesis investigates these effects for CrN-based materials, and how to control the growth of them in a DC-magnetron sputtering system.First, an optimization study for CrN was made, here the power was fixed while the temperature and nitrogen content were varied. Second, the effect of in-situ annealing at the deposition temperature was investigated. Here, both films with pure CrN and films with a mix of CrN and Cr2N were annealed. It was found that temperature, pressure, and ambient gas have a large effect on the decomposition of CrN to Cr2N. Third, alloying with V and Mo was implemented. It was found that Mo quickly breaks the rock-salt structure, and for further investigation of CrMoN and Cr(Mo,V)N systems, other deposition methods which allows for lower deposition rates need to be investigated.The sample deemed best was the CrVN-sample, showing a Seebeck coefficient of -141 μV/K, resistivity of 1520 μΩ∙cm and a power factor of 1.3 mW/mK2.

Safe, effective hydrogen fuel cells are one of the contenders for the next shift in mobile power technology. One of the solutions to the inherent risks of high pressure hydrogen fuel cells is an outer low pressure container with an inner high pressure containers containing a micro-electromechanical systems (MEMS) valve which regulating the pressure. These MEMS valves consist of several etched Si-chips stacked and bonded, which shall withstand the pressure and temperature range in the high pressure fuel cell as well as the embrittlement caused by the hydrogen gas. Hydrogen embrittlement is a phenomena where materials, mostly metals, lose their ductility due to diffusion of hydrogen atoms into their grain boundaries. A suitable method for stacking the chips is needed and thus a literature study was conducted. Several chip-to-chip bonding methods were investigated in the purpose of finding the most suitable methods tolerating temperatures between -40 to 85°C, pressure up to 1000 bar, hermetically sealing, withstanding hydrogen embrittlement and still bond with particulate contaminations caused by testing each chip. The method found to be best fitting for the purpose was anodic bonding with an alkali glass. Alternatively anodic bonding with a ceramic glass system could be considered if technique from alkali glass is adaptable.

The thesis focuses on the gas flow profile optimization of a non-conventional injector in a hot-wall MOCVD system. The injector’s gas flow profile is simulated with CFD and demonstrates awell-behaved laminar flow with a parabolic profile. To ensure the theory is in coherence with the reality, a qualitative study with five thermocouples in a test graphite piece of the was performed. First the thesis will take you through an introduction of the semiconductor field to arrive in a problem formulation. Then you will read about the principles of MOCVD systems, fluid dynamics principles and thermocouple theory. The experiment’s way of approach is thendescribed through all steps from blue print to results. A discussion about the result and the conclusion will be read before the proposals of future work based on the thesis work. The laminar flow is confirmed according to the resulting data and the limitations of the system is set to two different cases depending on background temperature. At 1000 °C a laminar flow is strongly indicated to be obtained at position 3A, closest to the growth area, within the gas flow range of 25 SLM regardless of background pressure, except for 700 mBar indicating turbulent flow for 15 SLM an up. At 20 and 200 mBar the laminar flow limit is suggested by data to be even higher and reaching a value of 35 SLM. At 450 °C the data indicate a laminar flow up to 20 SLM at position 3A regardless of background pressure condition, except for 700 mBar where the data indicate a laminar flow at 35 and 40 SLM. 50 mBar strongly indicates a laminar flow profile up to a gas flow of 35 SLM. With a background pressure of 20 mBar, the data suggests a laminar flow profile up to at least 25 SLM. At 100 mBar the data indicates a laminar flow within the range of 30 SLM.

This exam report includes a survey of surface treatment materials and their associated surface treatment methods for application in a tissue machine commissioned by Valmet AB. The tissue machine produces 24 hours a day in a demanding environment consisting of water, heat, oils, glue, dust and various chemicals. The demanding environment makes it difficult to maintain the machine clean due to the limited access at various machine parts when the machine is operating, which can lead to both personal risks and risks for production stoppages. These factors form the basis for the build-ups that takes place at various machine parts. Mostly, it’s about paper fibres that either are loose and dry or clustered into lumps. They also appear as lumps of fibres held together by oil, glues or other chemicals. Over time, they can loosen and, in the worst case, are due to breakages and production failures. The build-ups can also destroy the function of moving machine parts or lead to corrosion. The commission was assigned by Bengt O Andersson and Mickey Lindevall at Valmet AB. The project was conducted as the examining part in the course Degree Project for the Bachelor of Science in Mechanical Engineering, MSGC17, at the faculty of health, science and technology at Karlstad university. The project was carried out individually by a student at the Bachelor of Science program in Mechanical Engineering at Karlstad university. This degree project has taken precedence where the previous degree project at Valmet AB completed its work. The previous degree project has served as a reference document in this report to work out a requirement specification and identifying machine parts that are desired to undergo some form of surface treatment. The acting environments that exist at the various machine parts that are desired to be surface treated have also been examined from the previous degree project. This report has taken a different approach compared to the previous thesis work and is instead directed towards finding suitable surface treatment materials and associated application methods using the material database, CES EduPack. The purpose of the degree project has been to present suitable surface treatment materials and associated surface treatment methods. These are to solve the existing problems, thus facilitating cleaning and maintenance of the tissue machine. To achieve this, a list of suitable materials and associated surface treatment methods has been presented. From this list, conclusions are drawn to find as good surface treatment materials and its associated application methods as possible. With these, the problem should be eliminated or reduced drastically for the number of build-ups regarding the treated machine parts. The objective for this project thesis has been to analyse and proposing suitable methods and materials for surface treatments. With the chosen method and material for the surface treatment, the surfaces upon application are to achieve such properties that build-ups do not adhere to them. The project also contains a requirement specification that has been translated into restriction terms that all investigated material candidates have had to fulfil to be classified as suitable material candidates. The report has also taken a stand to the literature and theory available in the subject area to further investigate what materials are currently used in similar industrial applications. The information that has been processed has, in a final phase, been used as a basis for the list of suitable surface treatment materials and their associated surface treatment methods presented in the report. / Denna examensrapport innefattar en undersökning av ytbehandlingsmaterial samt tillhörande ytbehandlingsmetoder för applicering i en mjukpappersmaskin på uppdrag av Valmet AB. Mjukpappersmaskinen producerar 24 timmar om dygnet i en krävande miljö bl.a. bestående av vatten, värme, oljor, lim, damm samt diverse kemikalier. Den krävande miljön gör att det är svårt att hålla maskinen ren eftersom att det är svårt att komma åt överallt under drift, vilket kan medföra både personrisker och risker för produktionsstopp. Dessa faktorer ligger till grund för att uppbyggningar uppstår vid diverse maskindelar. Mestadels handlar det om pappersfibrer som endera är lösa torra eller fasttorkade i klumpar men de förekommer även som klumpar av fibrer som hålls ihop av olja, lim eller andra kemikalier. Med tiden så kan dessa lossna och ligger i värsta fall till grund för banbrott och produktionsbortfall. Uppbyggningarna kan även förstöra funktionen på rörliga maskindelar eller leda till korrosion. Uppdraget är utgivet av Bengt O Andersson och Mickey Lindevall på Valmet AB. Projektet utförs som den examinerande delen i kursen Examensarbete för högskoleingenjörsexamen i Maskinteknik, MSGC17 vid fakulteten för hälsa, natur- och teknikvetenskap vid Karlstads universitet. Projektet har utförts enskilt av studerande vid Högskoleingenjörsprogrammet i Maskinteknik vid Karlstads universitet. Detta examensarbete har tagit vid där föregående examensarbetare vid Valmet AB avslutade sitt arbete. Dennes examensrapport har fungerat som ett referensdokument i denna rapport för att kunna arbeta fram en kravspecifikation samt identifiera maskindelar som önskas genomgå någon form av ytbehandling. De verkande miljöerna som existerar vid de maskindelar som önskas ytbehandlas har även undersökts från det tidigare examensarbetet. Denna rapport har tagit ett nytt tillvägagångssätt gentemot föregående examensarbetare och riktas istället mot att identifiera lämpliga ytbehandlingsmaterial samt tillhörande applikationsmetoder med hjälp av materialdatabasen, CES EduPack. Syftet med detta examensarbete har varit att presentera lämpliga ytbehandlingsmaterial samt tillhörande ytbehandlingsmetoder som löser de befintliga problemen och därmed underlättar rengöring och underhåll av mjukpappersmaskinen. För att kunna göra detta har en lista av lämpliga material samt tillhörande ytbehandlingsmetoder tagits fram. Ur denna lista med material och ytbehandlingsmetoder dras slutsatser för att hitta ett så bra ytbehandlingsmaterial och tillhörande ytbehandlingsmetod som möjligt. Med dessa skall problemet elimineras eller minskas drastiskt gällande antal uppbyggningar vid behandlade maskindelar. Examensarbetet har som mål att analysera och ge förslag på lämpliga metoder och material för ytbehandlingar. Med vald metod och material för ytbehandling skall ytorna vid applicering få en sådan egenskap att uppbyggningar inte vidhäftar vid dessa. Projektet innehåller även en kravspecifikation som översatts till restriktionsvillkor som samtliga undersökta materialkandidater varit tvungna att passera för att klassas som lämpliga materialkandidater. Rapporten har även tagit ställning till den litteratur och teori som funnits tillgänglig inom ämnesområdet för att vidare undersöka vilka material som används i dagsläget inom liknande industriella tillämpningar. Informationen som tagits fram har i ett slutskede legat som grund för den lista av lämpliga ytbehandlingsmaterial samt dess tillhörande ytbehandlingsmetoder som presenteras i rapporten.

Induction hardening is a complex process that requires regular verification of the case depth and the microstructure. Today this verification is done by destructive testing where a cross section is analysed. The case depth is measured by several Vickers hardness impressions and the microstructure is analysed by a light optic microscope. This master thesis was performed in collaboration with Volvo GTO in Skövde, with the target to find out if an ultrasonic backscattering method is usable for analysing the case depths on induction hardened crankshafts. This was done by verifying the results provided by ultrasonic testing with the results provided by destructive testing. The measurements were done on several crankshafts with different case depths and steel composition. The result, for crankshafts with normal case depths, shows a good correlation between the destructive testing (DT) and the ultrasonic testing (UT). The mean value for the discrepancy was 0.39 mm with a standard deviation of 0.20 mm. The reproducibility of the method has a standard deviation of 0.074 mm.

Additive Manufacturing (AM) for metals includes is a group of production methodst hat use a layer-by-layer approach to directly manufacture final parts. In recent years, the production rate and material quality of additive manufactured materials have improved rapidly which has gained increased interest from the industry to use AM not only for prototyping, but for serial production. AM offers a greater design freedom, compared to conventional production methods, which allows for parts with new innovative design. This is very attractive to the aerospace industry, in which parts could be designed to have reduced weight and improved performance contributing to reduced fuel consumption, increased payload and extended flight range. There are, however, challenges yet to solve before the potential of AM could be fully utilized in aerospace applications. One of the major challenges is how to deal with the poor fatigue behaviour of AM material with rough as-built surface. The aim of this thesis is to increase the knowledge of how AM can be used for high performance industrial parts by investigating the fatigue behaviour of the titanium alloy Ti6Al4V produced with different AM processes. Foremost, the intention is to improve the understanding of how rough as-built AM surfaces in combination with AM built geometrical notches affects the fatigue properties.This was done by performing constant amplitude fatigue testing to compare different combinations of AM material produced by Electron Beam Melting(EBM) and Laser Sintering (LS) with machined or rough as-built surfaces with or without geometrical notches and Hot Isostatic Pressing (HIP) treatment. Furthermore, the material response can be different between constant amplitude and variable amplitude fatigue loading due to effects of overloads and local plastic deformations. The results from constant amplitude testing were used to predict the fatigue life for variable amplitude loading by cumulative damage approach and these predictions were then verified by experimental variable amplitude testing. The constant amplitude fatigue strength of material with rough as-built surfaces was found to be 65-75 % lower, compared to conventional wrought bar, in which HIP treatments had neglectable influence on the fatigue strength. Furthermore, the fatigue life predictions with cumulative damage calculations showed good agreement with the experimental results which indicates that a cumulative damage approach can be used, at least for a tensile dominated load sequences, to predict the fatigue behaviour of additive manufactured Ti6Al4V.

This master thesis work is performed at ABB Corporate Research Center inVästerås. The aim of this study is to investigate Ag:graphene composites as slidingelectrical contacts, suitable for use in e.g. tap-changers. Three different graphenematerials, all produced by a low-cost exfoliation process, are evaluated in this study. The results are compred to an ongoing work on Ag:GO (graphene oxide) composites. This material has shown very good tribological properties, however it hasbeen difficult to handle during sintering processing. The goal of this study is to geteven better tribological, electrical and mechanical properties than Ag:GO, and also todevelop a new powder-metallurgical method to produce the Ag:graphene composites.The study also investigates the influence of graphene flake size and concentration aswell as microstructure of the Ag:graphene composites. This report focuses on aninvestigation of the graphene raw material quality from the suppliers, and friction,wear and resistance analysis of the composites. This is done by using Ramanspectroscopy, SEM with EDS, LOM, tribometer tests and resistivity analysis. Raman and SEM analyses show that none of the supplied LEG materials are ofhigh-quality G (single or bilayer), but rather multi-layer graphene or even graphite.Small amounts of graphene added to Ag gave extremly low friction (μ<0.2 vs. pureAg μ~1.3, 5 N load and 5 cm/s speed). The composite manufacturing process hadcritical steps, which have to be optimized, to obtain low values of friction. Severedegassing of the composites was observed for some sampes, but the samples stillmaintained good friction values. SEM and EDS analyses of 2dfab’s wear track show abuild-up thin carbon-containing tribofilm on the Ag surface. Indicating that G ispresent, and works as a lubricant, creating good tribological properties. The resultsfrom this project may for sure be of importance for future ABB products in specificindustrial applications.

The task of this master thesis was to investigate the possibility of using transparent solar panels as windows and how they compare to other solar energy technologies. The idea is then to use the UV and IR light to produce energy while letting the visual light pass through. With this also receiving the advantage of less indoor heating of the building and therefore a decreased need for cooling. To make it into a more concrete example the Sergelhuset building in Stockholm, Sweden was chosen as an example. The investigation was made through a solar irradiation simulation for four different cases and an environmental analysis of the alternatives. The result is that the most common way of mounting polycrystalline modules, is the most cost effective alternative but it might not be so good from an environmental perspective in Sweden because of the already low g CO2eq/kWh and not the best location for solar panels. Façade mounted CIGS perform well in energy production but the high investment costs set it down. However, it is better than polycrystalline panels from an environmental perspective. The semitransparent CdTe window will be hard to make economically viable and from an environmental perspective it is debatable. The transparent alternatives focus its absorption on UV and IR light but there are also semi-transparent alternatives that uses also part of the visible light, which makes it not completely transparent.

Additive manufacturing (AM), also known as 3D printing, is a concept and method of a manufacturing process that builds a three-dimensional object layer-by-layer. Opposite to the conventional subtractive manufacturing, it conquers various limitations on component design freedom and raises interest in various fields, including aerospace, automotive and medical applications. This thesis studies the mechanical behavior of thin-walled component manufactured by a common AM technique, laser powder bed fusion (LPBF). The studied material is Hastelloy X, which is a Ni-based superalloy, and it is in connection to a component repair application in gas turbines. The influence of microstructure on the deformation mechanisms at elevated temperatures is systematically investigated. This study aims for a fundamental and universal study that can apply to different material grades with FCC crystallographic structure. It is common to find elongated grain and subgrain structure caused by the directional laser energy input in the LPBF process, which is related to the different printing parameters and brands of equipment. This thesis will start with the study of scan rotation effect on stainless steel 316L in an EOS M290 equipment. The statistic texture analysis by using neutron diffraction reveals a clear transition when different level of scan rotation is applied. Scan rotation of 67° is a standard printing parameter with intention to lower anisotropy, yet, the elongated grain and cell structure is still found in the as-built microstructure. Therefore, the anisotropic mechanical behavior study is carried out on the sample printed with scan rotation of 67° in this thesis. Thin-walled effects in LPBF are investigated by studying a group of plate-like HX specimens, with different nominal thicknesses from 4mm down to 1mm, and a reference group of rod-like sample with a diameter of 18mm. A texture similar to Goss texture is found in rod-like sample, and it becomes <011>//BD fiber texture in the 4mm specimen, then it turns to be <001> fiber texture along the transverse direction (TD) in the 1mm specimen. Tensile tests with the strain rate of 10−3 s−1 have been applied to the plate-like specimens from room temperature up to 700 ℃. A degradation of strength is shown when the sample becomes thinner, which is assumed to be due to the overestimated load bearing cross-section since the as-built surface is rough. A cross-section calibration method is proposed by reducing the surface roughness, and a selection of proper roughness parameters is demonstrated with the consideration of the calculated Taylor’s factor and the residual stress. The large thermal gradient during the LPBF process induces high dislocation density and strengthens the material, hence, the LPBF HX exhibits better yield strength than conventionally manufactured, wrought HX, but the work hardening capacity and ductility are sacrificed at the same time. Two types of loading condition reveal the anisotropic mechanical behavior, where the vertical and horizontal tests refer to the loading direction being on the BD and TD respectively. The vertical tests exhibit lower strength but better ductility that is related to the larger lattice rotation observed from the samples with different deformation level. Meanwhile, the elongated grain structure and grain boundary embrittlement are responsible for the low horizontal ductility. A ductile to brittle transition is traced at 700 ℃, so a further study with two different slow strain rates, 10−5 s−1 and 10−6 s−1, are carried out at 700 ℃. Creep damage is shown in the slow strain rates testing. Deformation twinning is found only in the vertical tests where it forms mostly in the twin favorable <111> oriented grain along the LD. The large lattice rotation and the deformation twinning make the vertical ductility remain high level under the slow strain rates. The slow strain rate tensile testing lightens the understanding of creep behavior in LPBF Ni-based superalloys. In summary, this thesis uncovers the tensile behavior of LPBF HX with different variations, including geometry-dependence, temperature-dependence, crystallographic texture-dependence and strain rate-dependence. The generated knowledge will be beneficial to the future study of different mechanical behavior such as fatigue and creep, and it will also enable a more robust design for LPBF applications. / Additiv tillverkning, eller 3D-utskrifter, är tillverkningsmetoder där man skapar ett tredimensionellt objekt genom att tillföra material lager for lager. Till skillnad från konventionella avverkande tillverkningsmetoder elimineras många geometriska begränsningar vilket ger större designfrihet och metoderna har därför väckt stort intresse inom en rad olika områden, inklusive flyg-, fordons- och medicinska tillämpningar. I denna avhandling studeras mekaniska egenskaper hos tunnväggiga komponenter tillverkade med en vanligt förekommande laserbaserad pulverbädds-teknik, laser powder bed fusion (LPBF). Det studerade materialet är Hastelloy X, en Ni-baserad superlegering som är vanligt förekommande for både nytillverkning och reparation av komponenter för gasturbiner. Inverkan av mikrostruktur på deformationsmekanismerna vid förhöjda temperaturer undersöks systematiskt. Detta arbete syftar till att ge grundläggande och generisk kunskap som kan tillämpas på olika materialtyper med en kubiskt tätpackad (FCC) kristallstruktur. Det är vanligt att man hittar en utdragen kornstruktur orsakad av den riktade tillförseln av laserenergi i LPBF-processen, vilket kan relateras till olika processparametrar och kan variera mellan utrustningar frän olika leverantörer. Denna avhandling inleds med studien av effekten av scanningsstrategi vid tillverkning av rostfritt stål 316L i en EOS M290-utrustning. En statistisk texturanalys med hjälp av neutrondiffraktion påvisar en tydlig övergång mellan olika mikrostrukturer när olika scanningsstrategier tillämpas. En scanningsrotation på 67 mellan varje lager är en typisk standardinställning med avsikt att sanka anisotropin i materialet, dock finns den utdragna kornstrukturen oftast kvar. I denna avhandling studeras därför de anisotropa egenskaperna hos material tillverkade med 67 scanningsrotation. Effekten av tunnväggiga strukturer i LPBF undersöks genom att studera en uppsättning platta HX-prover, med olika nominella tjocklekar från 4 mm ner till 1 mm, samt en referensgrupp med cylindriska prov med en diameter på 18 mm. Kristallografisk textur som liknar den av Goss-typ återfinns i de cylindriska proverna vilket gradvis övergår från en fibertextur med <011> i byggriktningen for 4mm-proven till en fibertextur med <001> i tvärriktningen for 1mm-proven. Dragprovning med en töjningshastighet på 10−3 s−1 har utförts på de platta provstavarna från rumstemperatur upp till 700 ℃. En sänkning av styrkan uppvisas när proven blir tunnare, vilket kan antas bero på att det lastbarande tvärsnittet överskattas på grund av den grova ytan. En metod för tvärsnittskalibrering föreslås genom att kompensera for ytråheten, och valet av lämplig ytfinhetsparameter motiveras med hänsyn till den beräknade Taylor-faktorn och förekomsten av restspänningar. Den stora termiska gradienten som uppstår for LPBF-processen inducerar en hög dislokationstäthet vilket höjer materialets styrka och följaktligen uppvisar LPBF HX högre sträckgräns an konventionellt tillverkad, smidda HX, men förmågan till deformationshårdnande samt duktiliteten i materialet sänks samtidigt. Tester utförda i två olika belastningsriktningar, vertikalt respektive horisontellt mot byggriktningen, demonstrerar det anisotropiska mekaniska beteendet. De vertikala testerna uppvisar lägre hållfasthet men bättre duktilitet vilket kan relateras till en större benägenhet for kristallstukturen att rotera när deformationsgraden ökar. Samtidigt är den utdragna kronstukturen ansvarig for den lägre duktiliteten for de horisontella proverna. En övergång från ett duktilt till ett mer sprött beteende noterades vid 700 ℃, och därför initierades ytterligare en studie där tester med två lägre töjningshastigheter, 10−5 s−1 och 10−6 s−1, utfördes vid 700 ℃. Det kan noteras att krypskador återfinns i tester med en långsam deformationshastighet och deformationstvillingar uppstår endast i de vertikala provstavarna där det främst bildas tvillingar i korn orienterade med <111> riktningen längs belastningsriktningen. Den stora förmågan till rotation i kristallstrukturen och deformationstvillingarna bidrar till att den vertikala duktiliteten förblir hög även i testerna med en låg deformationshastighet. Testerna med en långsam draghastighet bidrar därför till en bättre förståelse av krypbeteendet i LPBF Nibaserade superlegeringar. Sammanfattningsvis så bidrar denna avhandling till bättre förståelse av de mekaniska egenskaperna hos LPBF HX i olika utföranden och förhållanden, inklusive geometriberoende, temperaturberoende, deformationshastighetsberoende samt inverkan av kristallografisk textur. Den genererade kunskapen kommer att vara till stor nytta vid fortsatta studier av olika mekaniska egenskaper som utmattning och kryp, samt bidrar till att möjliggöra en mer robust design for LPBF-tillämpningar.

Skogsbränder utgör ett stort problem både lokalt, regionalt och globalt. De förstör stora värden, frigör stora mängder kol ut i atmosfären och är mycket resurskrävande att bekämpa. Under markytan kan glödbränder fortsätta långt efter att flambranden ovan mark är släckt. Glödbränder brinner mycket långsammare än de öppna flambränderna, men är istället svårare att upptäcka och ställer andra krav vid bekämpning. En typ av glödbrand som kan påträffas i skogsbränder är torvbränder. Det är glödbränder som uppstår i torvmarker som utsatts för torka. Branden äter sig sakta igenom torven och kan gå djupt ner i marken. Svårigheter med att lokalisera bränderna och att få ner tillräckligt med vatten i de djupare torvlagerna gör dem svåra att släcka. Idag används ofta dimspikar, även kallade jordspett, för att släcka bränder som gått ner under markytan. På vissa ställen har även skärsläckaren börjat användas. Detta arbete syftar till att ge en bättre förståelse för de två verktygens funktion och effektivitet vid släckarbete av torvbränder. För att göra det har två tester genomförts på Luleå räddningstjänsts övningsfält, ett för dimspik och ett för skärsläckare. En försöksuppställning byggdes upp med en invändig tvärsnittsarea på 80×80 cm och en höjd på 1,1 m. Den fylldes sedan med torv som packades lätt tills torvlagret var 1 m tjockt. Det som undersöktes var verktygens penetreringstid för vattnet att nå 1 m ner i torven samt hur stor spridning vattnet fick över tvärsnittsarean på djupet 1 m. Båda verktygen hade liknande flöden (56 l/min för skärsläckaren och 58 l/min för dimspiken) så de uppmätta skillnaderna i resultat berodde på hur vattnet transporterades, inte på mängden vatten. Skärsläckaren slog igenom på cirka 1 sekund och bildade ett utgångshål på cirka 1 dm2, där det var blött ytterliga någon centimeter runtomkring för en total våt area på cirka 2 dm2. Testet avslutades efter 30 sekunder då ingen förändring kunde ses i storleken på utgångshålet och den våta arean från efter de första få sekunderna. Vattnet sprutade rakt igenom torven. Dimspiken vätte igenom efter 26 sekunder och den våta arean växte kontinuerligt. Inget utgångshål bildades i detta fall. När dimspiken stängdes av efter 1 minut och 45 sekunder, så hade cirka 32 dm2 blivit blött; vilket motsvarar ungefär halva tvärsnittarean hos försöksuppställningen. Spridning fortsatte efter att dimspiken slagits av och nästan hela tvärsnittsarean var blöt efter ytterligare några minuter. Skärsläckaren hade en mycket snabb penetreringstid, men sprutade istället mycket vatten rakt igenom torven, vilket medförde att stora mängder vatten passerade genom torven utan att väta en stor yta eller volym. Dimspiken hade en mycket längre penetreringstid, i gengäld så sköts inte vattnet rakt igenom torven utan spred ut sig och vätte en större yta. Båda verktygen har sina för- och nackdelar. Vilket verktyg som är bäst är väldigt situationsberoende. Skärsläckaren har bland annat snabbare penetreringstid och möjliggör fler snabba ingrepp, medan dimspiken täcker en större area per angreppspunkt och är lättare och säkrare att hantera. / Wildfires are a major problem both locally, regionally and globally. They destroy large values, emit large quantities of carbon into the atmosphere and are very resource intensive to fight. Smoldering fires can continue under the ground surface long after the flaming fire above ground is put out. Smoldering fires burn much slower than the flaming fires, but in turn they are harder to discover and require different means to fight. Peat fire is one type of smoldering fire that can be found in wildfires. It is a smoldering fire that occur in peatlands exposed to drought. The fire slowly eats its way through the peat and can go deep into the ground. Difficulty locating them and getting enough water into the deeper peat layers makes them difficult to extinguish. Today, fognails are often used to extinguish smoldering fires in the ground. The cutting extinguisher is another tool that has been used to fight smoldering fires in the ground in some cases. This bachelor thesis aims to provide a better understanding of the function and efficiency of the two tools in extinguishing peat fires. To do this, two tests have been carried out on the fire department’s training field in Luleå, one with a fognail and one with a cutting extinguisher. A test stand was constructed with an internal cross-sectional area of ​​80×80 cm and a height of 1.1 m. It was then filled with peat which was lightly packed until the peat layer was 1 m thick. What was investigated was the tools’ penetration time for the water to reach 1 m down into the peat and the size of the water spread over the cross-sectional area at the depth of 1 m. Both tools had similar flows (56 l/min for the cutter extinguisher and 58 l/min for the fognail) so the differences arose in how that water was used, not the amount of water. The cutting extinguisher broke through in about 1 second and formed an exit hole of about 1 dm2 with additional wetness of a few centimeters around for a total wet area of ​​about 2 dm2. The test was terminated after 30 seconds when no change could be seen in the size of the output hole or the wet area from after the first few seconds. The water sprayed right through the peat. The water from the fognail got through after 26 seconds and the wet area grew continuously. No exit hole was formed in this case. When the fognail was turned off after 1 minute and 45 seconds, about 32 dm2 had become wet, which corresponds to about half the cross-sectional area of the test stand. However, spreading continued despite the fognail being turned off and almost the entire cross-sectional area was wet after a few more minutes. The cutting extinguisher had a very fast penetration time, but as a result it sprayed a lot of water right through the peat without wetting a large area or volume. The fognail had a much longer penetration time, but in return, the water was not shot straight through the peat, but spread out and wet a larger surface. Both tools have their advantages and disadvantages. Which tool is the best depends a lot on the situation. The cutting extinguisher has, among other things, a faster penetration time and allows for more rapid interventions, while the fog nail covers a larger area per attack point and is easier and safer to handle.