Mechanisms of construction machines and selection of steels for the manufacture of welded metal structures

Abstract

The paper is devoted to the study of the working mechanisms of construction machines from the point of view of the selection of structural steels for the manufacture of welded metal structures. Special attention is paid to the operational reliability and durability of modern construction machines. It was found that the most suitable for the manufacture of welded structures are complex-alloyed low-carbon steels. They have high strength (σ0.2≥600 MPa, σB≥800 MPa), are characterized by sufficient plasticity and increased resistance to brittle fracture at low temperatures. In the selection process, special attention was paid to the properties that structural steels should simultaneously have, specifically: low sensitivity to various stress concentrators; adaptability to perform service functions that are envisaged in the development of the project and directly in the process of manufacturing the welded metal structure, good weldability. The experiments were carried out using the example of low-carbon and low-alloy steels. Special attention was paid to the analysis of the optimal modes of thermal cycling with the aim of obtaining final structures with a given degree of dispersion, typical of real metal structures. Taking into account the requirements for the reliability of construction machines in operating conditions at high and low temperatures, as well as taking into account various operational characteristics, the expediency of using ferromagnetic structural steels was substantiated.