DEFECT FORMATION ON SHELLS WITH ONE-WAY LEDGE WHILE ENLARGING WITH A PROFILED STEPPED INSTRUMENT
Journal Title: Вісник Кременчуцького національного університету імені Михайла Остроградського - Year 2018, Vol 1, Issue 109
Abstract
Purpose. To analyze the mechanism of formation of defects during the enlarging of hollow forgings with the stepped outer surface and to suggest ways to eliminate them. The article deals with defects formed during and after the enlarging of one-way ledge shells, which are used in the manufacture of pressure vessels. An example of the use of such shells in the power industry for the construction of high-pressure reactors is given. Methodology. To simulate the enlarging process, the DEFORM-3D program (temporary license of the DGMA) was used. This program is based on the finite element method. To implement the experiment, a planning method was used. There were three main planning schemes, depending on what part deformed at the initial stage 1 - ledge 2 - both salient and ledge 3 – salient. In order to maximally approximate experimental research to real conditions, it is necessary to meet to the basic conditions of the law of similarity. Lead was used to study the processes of hot metal processing under laboratory conditions, since this material is well processed and has a low temperature of recrystallization and melting. Results. It has been established that cramps occur on the ledge near the inclined site by using a profiled step die for enlarging shells with a one-way ledge. This is due to the small angle of inclination of the plot, which is 10°. In order to eliminate the defect, it is pro-posed to increase this angle to 30°. Another defect occurs in the case when at the initial stage the salient deforms of enlarging only. This defect consists in case of deforming the salient, part of the ledge deforms about the drow, increasing the diameter of the hole on this side. Avoid this defect will allow for staggering enlarging: preparatory with a degree of deformation 0,1-0,2 with a larger step and the final with the desired profile. Originality. For the first time, an enlarging of stepped hollow forgings was executed using a profiled die and the mechanism of formation of defects on the forgings received was investigated. Practical value. This research will allow to improve the quality and accuracy of the manufactured rails with a rope or a flange using a profiled die. References 19, figures 6.
Authors and Affiliations
М. Kosilov, O. Herasymenko, A. Khvashchynskyi
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