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Studies show that although commonly used steels are standardized, some of their mechanical properties (such as tensile strength) vary widely and knowledge of their corrosion behavior is insufficient. Additional treatments, such as plastic deformation, alter the structure of carbon steels and affect their properties. This article explores one of the most widely used materials in mechanical and civil engineering - steel S235. Two types of rods, 6 mm in diameter, from hot-rolled non-alloy structural steel (S235JR, BDS EN 10025-2: 2005) and bright cold drawn steel (S235JRC, BDS EN 10277-2: 2008) have been tested. Tensile tests have been carried out, stress-strain curves are constructed and compared, the main mechanical properties such as yield strength, tensile strength and modulus of elasticity are determined. The typical consequences of plastic deformation such as increased yield strength have been identified. The assessment of corrosion behavior was done by means of the weight loss method in a 3,5% NaCl water solution for 5 weeks. It was found out that in the studied period the two types of rod exhibit close corrosion resistance, with the tendency for the cold drawn steel to have a higher uniform corrosion rate over a longer period.

Metal structures corrosion is a problem of global economic importance. Typically, the corrosion process runs slowly, which requires accelerated methods for corrosion behaviour examination. The conditions when accelerated methods are used differ from the real ones, which affects the results obtained. One of the methods that relatively successfully reproduces corrosion in a natural atmosphere is included in the standard EN ISO 11130:2018 – Alternate immersion test in salt solution. Unlike other widespread methods, uneven corrosion occurs here, including spots and pits, which greatly affect the mechanical behaviour of the material. The commercial devices for such tests are quite expensive. This justifies the development and production of one’s own equipment as the one presented in this paper. The design, construction and production of a low-cost device are hereby described. The first results of the tests performed with this machine are also given. The corrosion rate of rods, 6 mm in diameter, from widely used steel grades – S235JR and S235JRC – was determined. The duration of the test was 42 days. The results were compared with those from another corrosion test method with the same duration – immersion in a solution of 3.5% NaCl.

Abstract. This paper analyzes stresses in a link of a slat chain conveyor loaded with rock mass. Tensometric data and results from numerical simulation with Finite Element Method (FEM) are used. The tensometric measurements are performed in real life conditions. For numerical simulation an adequate model with FEM has been created. The adequacy of the model is confirmed by the comparison of the experimental and numerical results. The factor of safety used in the design of the conveyor links is determined.

Steel parts and structures are often used in an aggressive environment, which causes corrosion. Corrosion leads to deterioration of the mechanical properties of steel in two ways. First, it reduces the area of the carrying cross sections. Second, it increases surface defects, which are stress concentrators. Therefore, it is necessary to study the impact of corrosion on the mechanical properties of steel. The paper reviews the methods for causing corrosion of steel specimens for mechanical testing. The impact that the corrosion method and the degree of corrosion have on the mechanical properties of steel is also discussed.