3738 KB36 KB199920252015Fan, ChangfengLi, ChengkaiShi, YongjunXu, PengyunYi, Pengštevilka:1letnik:61str. 43-52, SI 8ISSN:0039-2480COBISSID:13857819URN:URN:NBN:SI:doc-JHU0U8OHenZveza strojnih inženirjev in tehnikov Slovenije et al.Strojniški vestniklasersko navarjanjelokalno predgrevanjemikrostrukturanumerični modelisiva litinaThe effect of dynamic local self-preheating in laser cladding on grey cast iron|In laser cladding, high cooling rates are accompanied by superior mechanical and metallurgical properties. However, these characteristics, along with the additive nature of the process, significantly contribute to the formation of thermal stresses, which are the main cause of any potential delamination and crack formation across the remelted area. To reduce thermal stress and better manage the microstructure, a strategy of dynamic local self-preheating has been designed. Laser-cladding experiments with no preheating, static global preheating, and dynamic local preheating with grey cast iron have been conducted. Parallel to the experimental investigations, numerical models have been established in order to study the temperature distributions and thermal stresses in different processes. The results indicate that dynamic local self-preheating contributes to reducing the transient thermal stress and residual stress compared with other methods. With self-preheating of the substrate, microstructures of the coarse-grained region are well-developed. The self-preheated sample reveals a more compact structure in the fusion area and can exhibit less cracking during the cladding processTemperatura se med postopkom laserskega navarjanja nenehno povečuje in zmanjšuje, to pa povzroča velike toplotne napetosti in pride lahko do delaminacije ter do nastanka razpok v pretaljenem delu. Reševanju tega problema je bilo posvečeno že veliko pozornosti, med ukrepi pa je predvsem predgrevanje osnovnega materiala v peči ali z induktivno tuljavo. Problem takšnega pristopa je predvsem v zahtevnosti in neprikladnosti. Članek podaja strategijo dinamičnega lokalnega samopredgrevanja za zmanjšanje toplotnih napetosti in boljši nadzor nad mikrostrukturo. Opravljeni so bili eksperimenti in numerični preračuni za preučitev procesa dinamičnega lokalnega samopredgrevanja in različnih parametrov predgrevanjaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo