The cutting tool inserts are used in different machining processes and are most often made out of cemented carbide and have different geometries depending on application. During the machining process, the insert is subjected to elevated temperatures and high pressure which cause the insert to be worn out. Depending on the cutting conditions different wear mechanism and wear types appear on the insert. One of the most common wear types are flank wear but according to experts there is a lack of publication in this area and there are not sufficient information about how flank wear affects the thermo-mechanical loads that act on the insert. The present project was performed together with AB Sandvik Coromant with the aim to develop a fundamental understanding of loads on worn cemented carbide inserts during metal cutting. An additional aim is to investigate to which degree of detail the thermo-mechanical loads on the flank wear land (VB) can be modeled with regards to e.g. the angle between the wear land and the cutting direction. This was executed by modeling a worn insert in CAD and then importing the model to the software AdvantEdge, to simulate the cutting process. The results from the simulations are presented with TecPlot as figures showing the temperature and pressure distributions on the insert as well as plots generated in MATLAB showing the contact pressure. While analysing the results it was partly found that varying the VB affected the distribution of load and stresses. It was also found that the temperature decreased as the angle of the flank wear decreased. The highest temperatures were present was along the part of the rake face closest to the cutting edge, as well as at the bottom of the VB. Possible future outlooks in this area of work is to investigate how to get a more refined mesh on the workpiece, in order to optimize the cutting process and its results.

Multi-material structures are increasingly used in vehicle bodies to reduce weight of cars. The use of these lightweight structures is driven by requirements to improve fuel economy and reduce CO2 emissions. The automotive industry has replaced conventional steel components by lighter metals such as aluminium alloy. This is done together with cutting weight of structures using more advanced strength steels. However, sound joining is still difficult to achieve due to differences in chemical and thermal properties.   This research aims to develop a new innovative welding technique for joining aluminium alloy to ultra-high strength steels. The technique is based on friction stir welding process while the non-consumable tool is made of an ordinary tool steel. Welding was done by penetrating the rotating tool from the aluminium side without penetrating into the steel surface. One grade of Al-Mg aluminium alloy was welded to ultra-high strength steels under lap joint configuration. Different types of steel surface coatings including uncoated, hot-dipped galvanised and electrogalvanised coating have been studied in order to investigate the influence of zinc on the joint properties. The correlation among welding parameters, microstructures, intermetallic formation and mechanical properties are demonstrated in this thesis.  Results have shown that friction stir welding can deliver fully strong joints between aluminium alloy and ultra-high strength steels. Two intermetallic phases, Al5Fe2 and Al13Fe4, were formed at the interface of Al to Fe regardless of surface coating conditions. The presence of zinc can improve joint strength especially at low heat input welding due to an increased atomic bonding at Al-Fe interface. The formation of intermetallic phases as well as their characteristics has been demonstrated in this thesis. The proposed welding mechanisms are given based on metallography investigations and related literature. / <p>QC 20170519</p>

Many educational systems of today are standards-based and aim at for alignment, i.e. consistency, among the components of the educational system: standards, teaching and assessment. To conclude whether the alignment is sufficiently high, analyses with a useful model are needed. This thesis investigates the usefulness of models for analyzing alignment between standards and assessments, with emphasis on one method: Bloom’s revised taxonomy. The thesis comprises an introduction and five articles that empirically investigate the usefulness of methods for alignment analyses. In the first article, the usefulness of different models for analyzing alignment between standards and assessment is theoretically and empirically compared based on a number of criteria. The results show that Bloom’s revised taxonomy is the most useful model. The second article investigates the usefulness of Bloom’s revised taxonomy for interpretation of standards in mathematics with two differently composed panels of judges. One panel consisted of teachers and the other panel of assessment experts. The results show that Bloom’s revised taxonomy is useful for interpretation of standards, but that many standards are multi-categorized (placed in more than one category). The results also show higher levels of intra- and inter-judge consistency for assessment experts than for teachers. The third article further investigates the usefulness of Bloom’s revised taxonomy for analyses of alignment between standards and assessment. The results show that Bloom’s revised taxonomy is useful for analyses of both standards and assessments. The fourth article studies whether vague and general standards can explain the large proportion of multi-categorized standards in mathematics. The strategy was to divide a set of standards into smaller substandards and then compare the usefulness and inter-judge consistency for categorization with Bloom’s revised taxonomy for undivided and divided standards. The results show that vague and general standards do not explain the large proportion of multi-categorized standards. Another explanation is related to the nature of mathematics that often intertwines conceptual and procedural knowledge. This was also studied in the article and the results indicate that this is a probable explanation. The fifth article focuses on another aspect of alignment between standards and assessment, namely the alignment between performance standards and cut-scores for a specific assessment. The validity of two standard-setting methods, the Angoff method and the borderline-group method, was investigated. The results show that both methods derived reasonable and trustworthy cut-scores, but also that there are potential problems with these methods. In the introductory part of the thesis, the empirical studies are summarized, contextualized and discussed. The discussion relates alignment to validity issues for assessments and relates the obtained empirical results to theoretical assumptions and applied implications. One conclusion of the thesis is that Bloom’s revised taxonomy is useful for analyses of alignment between standards and assessments. Another conclusion is that the two standard setting methods derive reasonable and trustworthy results. It is preferable if an alignment model can be used both for alignment analyses and in ongoing practice for increasing alignment. Bloom’s revised taxonomy has the potential for being such an alignment model. This thesis has found this taxonomy useful for alignment analyses, but its’ usefulness for increasing alignment in ongoing practice has to be investigated.

Thermal Barrier Coatings (TBCs) are advanced material systems that are being used in the hot sections of gas turbines such as combustor, turbine blades, and vanes. The top ceramic coating in TBCs provides insulation against the hot gases and the intermediate metallic bond coat provides oxidation and corrosion resistance to the underlying turbine components. Durability of thermal barrier coatings is very important for the overall performance of the gas turbine. TBCs can fail in several different ways and there is a combination of more than one failure mechanism in most situations. One of the most widely used TBC is atmospheric plasma sprayed (APS) yttria stabilized zirconia (YSZ). Both the deposition technique and the TBC material have certain limitations. The main aim of this research is to study new TBC materials and/or new deposition techniques and compare with the conventional YSZ and understand their failure mechanisms during cyclic oxidation and hot corrosion. Thermal cyclic oxidation of a newly developed high purity nano YSZ thermal barrier coating has been studied. Cross sectional analysis of exposed as well as completely failed samples showed a mixed-type failure caused by crack propagation parallel to the bond coat/top coat interface. The majority of the damage occurred towards the end of the coating life. A finite element model has been developed to study the probability of crack growth along different paths that leads to the final failure. Hot corrosion mechanism in suspension plasma sprayed two-layer gadolinium zirconate/YSZ, three-layer dense gadolinium zirconate/gadolinium zirconate/YSZ, and a single-layer YSZ has been studied in the presence of sodium sulfate and vanadium pentoxide. The test results showed that gadolinium zirconate coatings were more susceptible to corrosion compared to YSZ coatings despite gadolinium zirconate coatings having lower reactivity with the corrosive salts. Thermal cycling behavior of a high chromium bond coat has been studied. Cross-sectional analysis showed formation of sandwich type microstructure with chromium rich oxide and alumina as the top and the bottom layers. Inter-diffusion of minor elements between different MCrAlY coatings – substrate systems has been studied using, diffusion simulation software, DICTRA. The simulation results showed that the diffusion of minor elements in the coatings is dependent on the rate of β phase depletion in the beginning. After the depletion of β phase there was no clear dependence of the coating composition on the diffusion of minor elements.

A routine non-destructive test method based on Phased Array Ultrasonic Testing (PAUT) has been developed and applied for the inspection of the first 11 T dipole prototype magnet half shell welds, and the test results are compared with the radiography and visual inspection results of the same welds. A manual scanner and alignment system have been developed and built to facilitate the inspection of the 5.5 m long welds, and to assure reproducibility of the PAUT results. Through the comparison of distance readings and signal amplitude for different focus lengths, a focal law with focus at 25 mm sound path has been selected for the routine inspection of the 15 mm thick austenitic stainless steel 11 T dipole welds. The defocusing properties (beam spread) due to the cylindrical geometry of the half shells and the sound path distance to the area of interest were taken into account. Dedicated sensitivity calibration weld samples with artificial defects (side-drilled-holes) have been designed and produced from 11 T dipole prototype austenitic stainless steel half shell welds. These provide representative calibration for the strongly attenuating and scattering austenitic stainless steel weld material. One scan with two phased array probes aligned parallel to the weld in 2 mm distance from the weld cap edge, and one scan with the probes aligned parallel to the weld in 12 mm distance from the weld cap edge are sufficient to show if the inspected welds fulfil the requirements of weld quality level B according to ISO 5817. The standard test duration for the two scans of the two 5.5 m long horizontal welds of the 11 T dipole magnets is about one day, provided that no defects are found that need to be characterized in more detail.

I denna rapport kan läsaren följa händelseförloppet med framtagningen av en fysisk mood-board med tillhörande grafisk manual. Läsaren kommer att få en allmän förståelse för hur det semantiska hos en produkt påverkar dess användare samt hur detta påverkar produktens resultat på marknaden. I projektet pressenteras en tämligen oanvänd metod som, kortfattat; syftar till att ta vara på en målgrupps specifika känslor om exempelvis en produkt för att göra denna mer optimerad. I detta projekt handlade det mer om att ta fram specifika strukturer vilka tillslut kom att leda till ett antal speciellt utvalda ytor och material åt företaget Tylö® AB. Materialet tillsammans med speciella ytor skall komma att skapa en mer elegant känsla i deras kommande sortiment. Metoden som används för att nå fram till resultatet heter Kansei Engineering. / This report handles the development of a graphic manual and a physical mood-board with specific number of surfaces for the sauna manufacturing company Tylö® AB in Halmstad. The reader will have a general understanding of how the semantic of a product affects its users, and how this affects the product's performance on the market. The project is based on a fairly unused method, which basically is used for; seize a target group specific feeling about a specific product to make it more optimized. In this project, it was more about the development of specific structures on surfaces, which eventually came to lead to a number of specially selected materials and surfaces for the company Tylö ® AB. The materials, together with special surfaces, probably come to create a more elegant feeling in their upcoming concepts. The method that was used to achieve the target is called Kansei Engineering.

This thesis concerns experimental investigations of laser cutting and piercing, with theoretical and practical discussions of the results. The thesis is made up of an introduction to laser cutting and six scientific Papers. These Papers are linked in such a way that each of them studies a different aspect of laser cutting: process efficiency in Paper I, morphology and melt flow on the laser cut front in Papers II, III and IV and laser piercing in Papers V and VI. Paper I investigates the effect of material type, material thickness, laser wavelength, and laser power on the efficiency of the cutting process for industrial state-of-the-art CO2 and fibre laser cutting machines. Here the cutting efficiency is defined in its most fundamental terms: as the area of cut edge created per Joule of laser energy. In Paper II a new experimental technique is presented which has been developed to enable high speed imaging of laser cut fronts produced using standard, commercial parameters. The results presented here suggest that the cut front produced when cutting 10 mm thick medium section stainless steel with a fibre laser and a nitrogen assist gas is covered in humps which themselves are covered in a thin layer of liquid. Paper III presents numerical simulations of the melt flow on a fibre laser ablation-driven processing front during remote fusion cutting, RFC. The simulations were validated with high speed imaging observations of the processing front. The simulation results provide explanations of the main liquid transport mechanisms on the processing front, based on information on the temperature, velocity and pressure fields involved. The results are of fundamental relevance for any process governed by a laser ablation induced front. In Paper IV cutting fronts created by CO2 and fibre lasers in stainless steel at thicknesses between 2 mm and 10 mm have been ‘frozen’ and their geometry has been measured. The resulting three-dimensional shapes have been curve fitted as ninth order polynomials. Various features of the cutting front geometry are discussed, including the lack of correlation of the cut front inclination with either the relevant Brewster angle or the inclination of the striations on the cut edge. In this paper, mathematical descriptions of the cutting fronts are obtained, which can be used as input parameters by any researcher in the field of laser cutting simulations. Paper V investigates the subject of laser piercing. Before any cut is started the laser needs to pierce the material. In this paper the laser piercing process is investigated using a wide range of laser pulse parameters, for stainless steel using a fibre laser. The results reveal the influence of pulse parameters on pierce time and pierced hole diameter. A high speed imaging camera was used to time the penetration event and to study the laser-material interactions involved in drilling the pierced holes. In Paper VI a ‘dynamic’ or ‘moving beam’, laser piercing technique is introduced for processing 15 mm thick stainless steel. One important aspect of laser piercing is the reliability of the process because industrial laser cutting machines are programmed for the minimum reliable pierce time. In this work a comparison was made between a stationary laser and a laser which moves along a circular trajectory with varying processing speeds. High speed imaging was employed during the piercing process to understand melt behavior inside the pierce hole. Throughout this work experimental techniques, including advanced high speed imaging, have been used in conjunction with simulations and theoretical analysis, to provide new knowledge for understanding and improving laser beam cutting and its associated piercing process.

Denna rapport sammanfattar och jämför två olika korrosionmetoder, Höganäs interna korrosionstest och korrosions test enligt VDA 230-214. Målet har varit att med dessa två tester som bakgrund, ta fram en ny metod som löser Höganäs problem med upprepbarhet. Genom att med noggrant utförande gått igenom processen för hårdlödning, beredning av syror, korrosionsprovning under 4 veckor och processen för undersökning av mikrostrukturen på lödningsfogen, så har man lyckats få ut ett kvantitativt resultat. Förbättringen av den interna korrosionsmetoden valdes att basera sig enbart på svavelsyran och samtidigt istället att bereda syralösningar genom att styra pH värdet mellan ett aggresivt och ett mindre aggresivt värde. Man valde också att jämföra två produkter som ska hålla samma korrosionsegenskaper, Brazelet F300 och Brazelet Ni613. Produkten F300 är utvecklade av Höganäs AB och skillnaden gentemot den licensierade produkten Ni613 är att F300 innehåller järn och mindre nickel. Tidigare utredningar har gjorts för att jämföra dessa produkterna men har visat olika resultat. Denna utredning har lett till en metod för att kvantifiera korrosionsmotståndet hos de olika loden istället för att bara visuellt bedöma om korrosionsmotståndet är bra eller dåligt. Denna metoden har även lett till framtida arbeten för utvärdering av andra syror. / This report summarizes and compares two different corrosion methods, Höganäs internal corrosion test and a corrosion test according to VDA 230-214. The goal has been to develop a new method that solves Höganäs problems with repeatability with these two tests as a background. By carefully studying the process of brazing, acid preparation, corrosion testing for 4 weeks and the microstructure testing process on the brazed joint, you have managed to get a quantitative result. The improvement of the internal corrosion method was chosen to be based on the sulfuric acid and preparing acid solutions by controlling the pH value between an aggressive and a less aggressive value. It was also chosen to compare two products that has the same corrosion properties, Brazelet F300 and Brazelet Ni613. The difference between F300 and Ni613 is that the F300 contains iron and less nickel. Previous investigations have been made to compare these products but have shown different results. This investigation has led to a method of quantifying the corrosion resistance of the different brazing instead of only visually judging whether the corrosion resistance is good or bad. This method will be used for future work to investigate other acids.

The thesis work is to show that the use of SLM (Additive Manufacturing) compared with the traditional process to make injection molds will have advantages in design, especially in waterways.  This thesis work gives seven different versions of design applied to the SLM method to analyze and compare them in Solidworks® and Moldflow® to figure out what design is suitable for the SLM method. Through analysis of different versions, the finding of this thesis work is that the conformal waterway of design and lighter but stead structure in the SLM method causes the SLM molds' cooling performance to be almost 15% better than the conventional way and shorten the production time by 18% per product. Based on the advantages of the SLM method in cooling system design and structure optimization, the company can use the SLM method in the production process to improve economic and environmental benefits.

The upward trend in internal combustion engine efficiency is likely driven by the depletion of fossil fuels. Since no replacement in sight can deliver energy comparable to the conventional oil, there is a need to use it more rationally and effectively. Thermal barrier coatings have been seen for a long time as a solutionto increase the thermal efficiency of gas turbine engines but suffer from the lackof strong applicability in internal combustion engines. This is due to the different restrictions when comparing the environment on the gas turbines and in internal combustion engines. To overcome this problem and, at the same time, expand the application field of thermal barrier coatings, more efforts need to be devoted.In this work, different top coat materials using various deposition techniques were evaluated and categorized in three different thermal barrier coating (TBC) architectures. The first was the lamellar yttria-stabilized zirconia (YSZ) top coat deposited by atmospheric plasma spray (APS), used as a reference sample. The second architecture was a columnar suspension plasma spray (SPS) TBC with YSZ and gadolinium zirconate (GZO) top coat. The SPS process can produce avariety of microstructures, and they were, for the first time, tested in an internal combustion engine. The third architecture was an SPS top coat, with an additional layer on the top, called a sealing layer of either metallic or ceramic material, both never investigated in a diesel engine application earlier. For the thermophysical properties investigation, a combination of laser flashanalysis (LFA) and modeling with object-oriented finite element (OOF) was employed to understand the properties in all the applications. The performance of the coatings was evaluated in two different ways, by thermal cyclic tests, basedon the TBCs behavior under cyclic thermal loads and by single-cylinder engine experiment. The characterization of the coatings was done by scanning electron microscope (SEM) before and after the thermal cyclic tests.The performance properties were correlated with coatings microstructure and thermophysical properties. It was shown that a columnar TBC produced by SPS had a superior engine efficiency in the single cylinder engine experiment.