Effects of iron-rich intermetallics and grain structure on semisolid tensile properties of Al-Cu 206 cast alloys near solidus temperature

The effects of iron-rich intermetallics and grain size on the semisolid tensile properties of Al-Cu 206 cast alloys near the solidus were evaluated in relation to the mush microstructure. Analyses of the stress–displacement curves showed that the damage expanded faster in the mush structure dominated by plate-like β-Fe compared to the mush structure dominated by Chinese script-like α-Fe. While there was no evidence of void formation on the β-Fe intermetallics, they blocked the interdendritic liquid channels and thus hindered liquid flow and feeding during semisolid deformation. In contrast, the interdendritic liquid flows more freely within the mush structure containing α-Fe. The tensile properties of the alloy containing α-Fe are generally higher than those containing β-Fe over the crucial liquid fraction range of ~0.6 to 2.8 pct, indicating that the latter alloy may be more susceptible to stress-related casting defects such as hot tearing. A comparison of the semisolid tensile properties of the alloy containing α-Fe with different grain sizes showed that the maximum stress and elongation of the alloy with finer grains were moderately higher for the liquid fractions of ~2.2 to 3.6 pct. The application of semisolid tensile properties for the evaluation of the hot tearing susceptibility of experimental alloys is discussed

Toimihenkilöstön perehdyttäminen KONE Hisseillä (KEF)

Opinnäytetyön toimeksianto saatiin KONE Hisseiltä ja sen tarkoituksena oli tutkia, millä tasolla yhtiön toimihenkilöstön perehdyttäminen tällä hetkellä on. Tutkimuksen kohteena oli nimenomaan se, kohtaavatko esimiesten ja perehdytettyjen toimihenkilöiden näkemykset perehdytyksen onnistumisesta. Tämä suhteutettiin myös KONEen omaan henkilöstönjohtamispolitiikkaan, sen edellytyksiin ja tavoitteisiin. Tarkoituksena oli myös löytää mahdollisiin epäkohtiin parannus- ja kehitysehdotuksia tehokkaamman perehdytyksen takaamiseksi. Tutkimus toteutettiin kvalitatiivisena tutkimuksena, sillä tulosten haluttiin olevan mahdollisimman luotettavia ja henkilökohtaiset kokemukset kuvaavat parhaiten perehdytyksen nykytilaa. Perehdytys käsitteenä tarkoittaa kaikkia niitä toimia, joiden avulla uusi työntekijä saadaan osaksi organisaatiota. Perehdytys on osa henkilöstöjohtamista, koska sen perimmäinen tarkoitus on lyhentää sitä aikaa, jossa uuden työntekijän työpanos muuttuu tuottavaksi resurssiksi. Koska yrityksen perimmäinen tarkoitus on tuottaa voittoa, tulee perehdytykseen suhtautua yhtä vakavasti kuin talousjohtamisenkin prosesseihin. Perehdytyksen merkitystä työntekijälle tai organisaatiolle ei voi liikaa korostaa. Perehdytyksen avulla työntekijän osaaminen, motivaatio ja yrityksen työskentelykulttuurin omaksuminen tehostuvat, työntekijä sitoutuu osaksi yritystä ja hänen osaamisensa kehittyy. Organisaatiolle on eniten hyötyä siihen ja sen tavoitteisiin sitoutuneesta henkilökunnasta, sillä motivoitunut henkilöstö tekee organisaation kannalta parasta tulosta. Aineisto tutkimusta varten kerättiin haastattelemalla KONE Hisseille vuoden aikana tullut uusi toimihenkilöstö ja sen perehdyttäjät. Haastattelumuotona käytettiin teemahaastattelua, joka toteutettiin yksilöhaastatteluna. Toimihenkilöille ja perehdyttäjille oli kummallekin omat teemakysymyksensä. Luotettavien tutkimustulosten saamiseksi haastateltaville painotettiin anonymiteetin säilymistä, jotta nämä voisivat kertoa kokemuksistaan mahdollisimman avoimesti. Tutkimuksessa selvisi, että KONE Hisseillä on käytössään kattava ja hyvin toteutettu perehdytysohjeistus sekä laaja valikoima perehdytysvälineitä. Käytännön toteutuksessa ongelmaksi kuitenkin koettiin perehdyttäjien asenne ja ajankäyttö perehdytykseen, sen valmisteluun, suunnitteluun ja toteutukseen. Lisäksi koettiin, ettei perehdytyksellä ole riittävää seurantaa. Kehittämisehdotuksena perehdyttäjien asenteisiin toimisi koulutus perehdytyksen tärkeydestä sekä perehdyttämisen valmisteluun, suunnitteluun sekä toteutukseen riittävän ajan varaamista ja siihen keskittymistä. Puuttuvaan seurantaan tulisi myös kiinnittää erityistä huomiota ja lisätä se kattamaan koko perehdytysprosessi.The request for this thesis was given by KONE Elevators and the purpose of it is to find out at what level the orientation and induction of the office employees is at this point. The focus on this survey is to find out do the experiences of the successfulness of the orientation concur between the new office employees and their supervisors. The results were also compared with KONE’s human resource management policy, its preconditions and goals. The purpose of this survey was also to find solutions and developments to possible grievances or disadvantages to ensure more efficient orientation. The survey was conducted as a qualitative study, because of its reliability and resulting personal experiences that are the best ways to find out the current situation of the orientation. Orientation as a concept means all those actions that are used to train new employees in the process of adaption and making them part of the company. Orientation is a part of the human resource management, because the main point of it is to minimize the time that it takes for the new employees work contribution to turn into producing resource. The main idea in any company is to make profit, and therefore one should take orientation as seriously as any economic management process. The significance of the orientation to both of the employee and the company can’t be overvalued. By orientation employee’s motivation, knowledge, skills and adoption of the work culture of the company are intensified and developed. Staff that are motivated and committed is the most useful and profitable to the company and makes the most profit as well. The material for this survey was collected by interviewing the new office employees hired within a year and their supervisors. The form of the interview was a theme interview and it was conducted as individual interviews. There were different questions to the office employees and to their supervisors. In order to get the most reliable results maintaining the anonymity was emphasized to the subjects so they could speak as openly as possible about their experiences. The research found out that in KONE Elevators they have excellent and very comprehensive orientation instructions and a large variety of orientation methods. In the practical implementation however were some problems with the attitudes of the supervisors and their time usage in the orientation. In addition it was found out that there is not enough surveillance in the orientation. To correct these problems there should be educational training about the importance of an excellent orientation to the supervisors. The supervisors also need more specified time for the preparation, planning, concentrating and conducting the orientation. Lacking surveillance is also something that should be considered and it should cover the whole orientation process

Effect of filling materials on microstructure and properties of CMT-laser beam oscillation hybrid welding behavior of dissimilar Al–Mg–Si alloys

Laser oscillation-assisted cold metal transfer hybrid welding was conducted on 2.0 mm-thick 6082 and a new 6xxx aluminum alloys. The influence of wire composition on microstructure and mechanical properties of the 6082 and new 6xxx alloy joints is studied. Our results show that, due to the difference in surface tension, the cross section of a joint filled with ER4047 wire typically presents a wider U-shape profile, while the ER5183 filled joint shows a relatively narrower V-shape profile. The average grain size of the ER5183 joint is smaller than that of the ER4047 joint. The ER4047 joint exhibits better fluidity, resulting in a higher proportion of high-angle boundaries compared to the ER5183 joint, which we attribute to the higher Si content. Equiaxed grains are also observed near the fusion boundary on the new 6xxx side, while no equiaxed grain formation is observed on the 6082 side. EDS data demonstrates severe elemental segregation in the center of weld and the partially melted zone, suggesting that multiple secondary phases form unevenly within inter-dendritic regions and grain boundaries of α-Al during the welding process. The microhardness of the weld zone and the heat-affected zone on both sides in the ER5183 joint is higher than that of the ER4047 joint. The corrosion test evidences that the ER5183 joint has a slightly better corrosion resistance than the ER4047 joint. Our findings provide a new understanding on joining of dissimilar Al–Mg–Si alloys and guide the selection of appropriate filling materials and welding processes

Formation of intermetallic phases in unrefined and refined AA6082 Al alloys investigated by using SEM-based ultramicrotomy tomography

The spatial arrangement, distribution and morphology of Fe bearing intermetallics in AA6082 alloys depends on the manufacturing process of the alloy and thus influences the macroscopic properties. Here, the microstructure of a near industrial scale casting AA6082 Al alloy fabricated by a direct chill casting, b Al 5Ti 1B grain refiner addition and c intensive melt shearing has been investigated by three dimensional visualization using SEM based serial ultramicrotomy tomography. The formation sequence of phases in AA6082 alloys is generally categorized into four stages formation of amp; 945; Al grains, Fe bearing intermetallics, Mg2Si phase, and eutectic rosettes. Results of three dimensional visualization of the microstructure indicated that TiB2 particles not only could nucleate Fe bearing amp; 946; intermetallics, but also could provide substrate for the formation of Fe bearing amp; 945; intermetallics and Mg2Si. A further deep analysis reveals that the essential condition for the formation of secondary phases such as Fe bearing intermetallics and Mg2Si phase is the build up of a supersaturated solute front at the amp; 945; Al solid liquid interface irrespective of the specific nucleation site. In addition, the results indicate that grain refinement processing causes the severe interconnectivity of Fe bearing amp; 945; intermetallics. However, the intensive melt shearing is a better manufacturing process because the intermetallics are more evenly distributed and refined than with the addition of the grain refiner, thereby improving the properties of the allo