ЧИСЛЕННОЕ МОДЕЛИРОВАНИЕ ДЕФОРМАЦИЙ В АДДИТИВНОМ ТЕХНОЛОГИЧЕСКОМ ПРОЦЕССЕ ЛАЗЕРНОЙ ПОРОШКОВОЙ НАПЛАВКИ

Abstract

This article discusses the modeling of the stress-strain state of products during laser powder surfacing using the example of a stepped tubular sample. To calibrate the model, a number of experiments were carried out using an additive powder with a fractional composition of 40–80 μm. During laser powder surfacing of samples, two-point thermometry was carried out, which is necessary for the subsequent calibration of the temperature problem. Powder surfacing was carried out in one layer with pauses between the deposited paths according to the surfacing modes. Helium and argon were used as shielding gases. The creation of an applied tool for the preliminary numerical assessment of warpage and residual stresses in blanks and DSE before carrying out repair technological operations using the powder laser cladding method, which allows for prompt approximate calculations, was the main task of the work. In the model, the element birth/death method was considered, which makes it possible to implement the appearance of hardfacing bodies and is the most convenient in this case. Warping modeling was carried out by dividing the welded part into tracks, which, in turn, are divided into hardfacing bodies. The next stage is the heatingand cooling of each elementary body along the surfacing trajectory, instead of modeling a moving heat source. Command inserts allow you to adjust the surfacing trajectory using automatic numbering of elementary bodies. The proposed technique makes it possible to quickly preprocess the problem and obtain sufficiently accurate calculation results in a short time. The results of modeling and real laser powder surfacing were compared. Verification of the developed model was carried out using the digitized outer surface of the existing experimental samples after surfacing. Calculations show sufficient computational accuracy of the model, however, the use of high-temperature properties of the powder material will reduce the calculation error.