Authors: R.Sh. Nabiullin

Title of the article: Assessment of stress-strain state and mechanical properties of metal structures of the boom head of EKG-20 excavator

Year: 2024, Issue: 4, Pages: 46-53

Branch of knowledge: 2.8.8. Geotechnology, Mining machines (engineering)

Index UDK: 622.232

DOI: 10.26730/1816-4528-2024-4-46-53

Abstract: It has been established that one of the main reasons for the destruction of metal structures of quarry excavators is degradation and aging of the metal. Changes in the physical and mechanical state of the metal during long-term operation, its aging and embrittlement under the influence of a number of factors, including due to alternating cyclic loads and thermal cycling, occur both in the base metal and in welded joints, as a rule, in the heat-affected zone, which leads to a sharp decrease in the reliable and safe performance of the entire structure. It has been established that in order to objectively assess the condition of the working equipment of mining excavators, it is necessary to apply a comprehensive methodology using several methods for assessing the condition of the metal structures of the working equipment. To assess the condition of the material of the excavator boom head, a complex methodology was used, including several basic methods, including the metal magnetic memory method and the method of indirect assessment of the characteristics of the mechanical properties of the material based on the parameters of the pyramidal imprint on the surface of the material after determining the Vickers hardness. Based on the analysis of existing empirical dependencies that determine the relationships between various mechanical properties of metal, namely indicators that can be determined by non-destructive testing methods, formulas are identified that reflect the correlation dependence of the relative narrowing with the Wickes hardness, as well as with the parameters of the pyramidal imprint on the material. The dependence of impact toughness with relative narrowing is found, which allows us to evaluate the material of the diagnosed structure and establish the tendency to brittle failure. The main elements of a methodology for assessing the actual condition of the base metal and welded joints of metal structures of working equipment have been developed using the example of the boom head of the EKG-20 excavator.

Key words: working equipment mining excavator metal structures stress concentration zone stress-strain state physical and mechanical properties of metal deformability index

Receiving date: 02.09.2024

Approval date: 15.10.2024

Publication date: 31.10.2024

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