Fractographic justification of fracture resistance loss in steel elements of overloaded machinery metal constructions
Article Sidebar
Main Article Content
Abstract
The problem related to the loss of resistance to brittle fracture in steel elements of the metal structure of loading equipment has been investigated. A fracto- graphic analysis was conducted at macro and micro levels on samples taken from two sections of the crane that underwent testing to determine their impact toughness. The selected samples covered the least and most loaded areas of the crane's metal structure to reflect the minimum and maximum levels of operational steel degradation. The assessment of metal degradation was carried out based on its resistance to brittle fracture. A correlation was established between the nature of the fracture, energy absorption, and indicators of resistance to brittle fracture. Special attention was given to the location of delamination along the direction of rolling during macro and microfracto- graphic studies. Macrofractographic analysis confirmed the general tendency of the metal to delaminate, especially along the fibers of the texture. This tendency varied for different sections of the crane's metal structure and depended on the level of operational stresses in the structural elements. It was found that longitudinal samples exhibited fractographic signs of delamination in the form of secondary cracks perpendicular to the fracture plane. The macrofracture of a sample from a loaded area revealed a significant amount of delamination, indicating their role in the propagation of fractures during impact tests. These results allow establishing a connection between the material's structure, its mechanical properties, and operational degra-dation, which is crucial for improving the reliability and safety of crane metal structures
Article Details
References
2. Nykyforchin H., Krechkovska H., Student O. Fractographic peculiarities of SCC of gas pipeline steel after its hydrogen assisted in-laboratory degra- dation. International conference on structural integrity and durability: Book of abstracts. University of Zagreb, 2017. P. 57-58.
3. The role of notch tip shape and radius on deformation mechanisms of 12Cr1MoV steel under impact loading. Part 1. Energy parameters of fracture/ S.V. Panin, P.O. Marus-chak, I.V. Vlasov et al. Fatigue and Fracture of Engineering Materials and Structures. 2017, V. 40 № 11. P. 586-596.
4. Nemchuk O.O., Krechkovska H.V. Fractographic substantiation of the loss of resistance to brittle fracture of steel after operation in the marine gantry crane elements. Metallofizika i Noveishie Tekhnologii. 2019. 41 (6). P. 825-836.
5. Arkhipov O.G., Borisenko V.A., Khoma M.S., Liubimova-Zinchenko O.V. (2016) Degradatsiya stalei v agresyvnykh seredovyshchakh, zalishkovyi resurs obladnannia i korozii monitorynh. Luhansk: Vyd-vo Skhidnoukrainskoho natsionalnoho universytetu im. V. Dalia, 2016. (in Ukrainian).
6. Babii L.O., Student O.Z. (2007) Povzuchnist u vodni ekspluatovanoyi stali 2,25 Cr-Mo. Problema resursu i bezpeky ekspluatatsii konstruktsii, mashyn ta sporud: Zb. naukovykh prats. 2007. (in Ukrainian).
7. Telovich R.V., Garasym Yu.A., Krechkovska H.V., Bondarevska N.O. (2018) Polipshennia struktury ta mekhanichnykh kharakterystyk kharchevaltsovanoi evtetoidnoi stali shvydkisnym termichnym obroblianniam. Metalofizyka i novitni tekhnolohii. 2018. (in Ukrainian).