Abstract
ABSTRACT The results of the temperature fields modelling, the kinetics of the dissimilar metals deposition and the nature of structural transformations during the formation of an additive multilayer structure from 17G1С и 30ХGС steels are presented. For computer simulation the COMSOL Multiphysics calculation package is used. In the paper the influence of temperature on the steel thermophysical parameters is taken into account. In order to improve the performance of the additive process, we studied the simultaneous effect of 3 arcs on the process of the deposit formation, the structural transformations kinetics and the diffusion processes of redistribution of alloying elements are examined. Calculations show that in order to reduce the stresses level between additive deposit and the back to 50 MPa, the back should be preheated with an arc without material deposition at the beginning of the deposition process. It is shown that the transit time between neighboringarc sources of heat should be maintained in the range from 5 to 30 s. It is established that at low arc power (1 kW) the ferrite-bainite structure predominantly forms in a deposit in which the share of bainite is 71 %, ferrite – 28 %, martensite ∼1 %. When using an arc of greater power (5 kW) in the deposit a bainite-martensitic structure is formed in which the share of bainite is ∼50 %, the share of martensite increases to 40 % and ferrite to 10 %. Increasing the arc power leads to increasing in the maximum temperature of the liquid bath to 1750–1850 °C, to increasing in the cooling rate to 15–25 °C/s and, as a result, to increasing the share of martensite in the structure ofthe deposited layers. The developed software can be used for mathematical modelling of the metallurgical additive process for forming products from various steels, titanium, aluminium and other alloys.
Published Version
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