تاثیرات خوردگی طبیعی در خواص شیمایی و مکانیکی فولادهای سازه ای
Abstract
1- Introduction
2- Test specimens
3- Methods for corrosion tests
4- Test results on the chemical properties of corroded specimens
5- Test results on the mechanical properties of corroded specimens
6- Concluding remarks
Declaration of Competing Interest
Acknowledgements
References
Abstract
The objective of the paper was to experimentally examine the effects of corrosion wear on the chemical and mechanical properties of structural steels. Naturally-progressed corrosion testing on structural steel specimens was conducted during a period of 12 months. Three types of structural steels were tested: mild steel (grade A), AH32 steel, and DH32 steel. Different conditions of the corrosive environment were applied with three dry or water-immersed conditions, namely air (dry), freshwater immersion and seawater immersion, and with three temperatures, namely room temperature (18 °C), 0 °C, and −۱۰ °C. The chemical and mechanical properties of structural steels were measured before and after the corrosion testing. Based on the test results, the characteristics of corrosion progression rate for structural steels were studied and reported in a separate paper [21, doi: https://doi.org//10.1080/17445302.2019.1664128]. It is concluded that corrosion does not affect the chemical and mechanical properties of structural steels. Details of the test database were documented.
Introduction
Steel is a common material used for the construction of naval, offshore, mechanical, and civil engineering structures. As steel structures get older, their safety and integrity can suffer from corrosion wear which is affected by various parameters of influence in the corrosive environment, including oxygen content, salinity, pH value of water, temperature, atmospheric pressure, suspended solids, velocity of water waves, together with various physical and chemical factors of material [1–۵]. Land-based steel structures may be exposed to the immersion of freshwaters or related humidity while the surfaces of steel ship and offshore structures at sea are usually touched on seawaters [6]. In winter season or Arctic area, the operational temperature of such structures is in sub-zero temperatures (or lower than the room temperature).
To evaluate the structural integrity with corrosion damage at the level of steel structural members or entire structures, it is essential to identify the chemical and mechanical properties of corroded structural steels, i.e., at the level of materials. It is generally considered that corrosion does not affect the chemical and mechanical properties of structural steels [3], but obvious evidences or test database are lacking in the literature and thus some studies attempted to derive computational models that the corrosion wear was dealt with as a parameter of influence on the mechanical properties of structural steels [7–۱۱]. The objective of this paper was to obtain the physical test database to investigate the effects of corrosion wear on the chemical and mechanical properties of structural steels, and ultimately to contribute to the prevention of such an unnecessary confusion on the issue.