Influence of animal slurry on carbon C35 steel with different microstructure at room temperature

Abstract

Steels are the basic construction materials used in machine building, construction and in the construction industry. These materials often work in contact with aggressive factors. When subjected to corrosion, they go to their natural oxidation state. Mainly carbon steel C35 is intended for quenching and tempering. The steel is most often used for the production of tools and machine elements that are subject to medium loads and at the same time are very resistant to abrasion. Different heat treatment conditions result in different microstructural structure of C35 steel, and therefore also its different properties, including corrosive ones. The corrosion of these steels is easy to control. It is usually superficial. One of the more complex corrosive environments is animal slurry. As a result, the corrosive effects of animal slurry are complex and time-varying. Slurry is a mixture of dung and urine. The aggressive corrosive constituents in slurry are urea, uric acid, naturally excreted chloride as well as ammonia or ammonium salts. The purpose of this article is to investigate corrosion resistance in different time (48, 96, 144, 192, 240, 288, 336 and 432 hours) using weight loss and profile roughness parameters of structural steel in grade C45 in natural water solution of animal slurry at room temperature (25C). The tests were carried out for steel subjected to normalizing annealing as well as hardening and tempering at 300C. In order to be able to compare the corrosion rate of stainless steels with steel C35, it was decided to carry out the tests based on the methodology of testing corrosion-resistant steels. Corrosion tests show that the tested steel in animal slurry as a corrosive environment is characterized by a different corrosion rate, the measure of which for C35 steel may be the surface roughness.