1 The influence of sea water corrosion on the resistance cracking performance of carbon steel Wang Limin1,*), Han Daoping1), Zhang Donghuan2) , Li Dunyi3), Geng Hui1) 1) Department of Science, Qingdao Technological University, Qingdao 266033, China; 2) School of Transportation and Vehicle Engineering, Shandong University of Technology, 255049 3 ) Institute of Mechanics，Chinese Academy of Sciences，Beijing 100190 China; * Corresponding author: wanglimin@qtech.edu.cn Abstract As carbon steel immersed in seawater with loading, particularly with defect, its performance lead degradation and reduction in bear capacity. For the specimen of carbon steel immersed in seawater with notch and defects, its macro-mechanical properties was tested and also analyzed with electron microscopy equipment. The fracture behavior of specimen was analyzed in different test conditions, and their bearing capacity was contrast each other for loading before and after soaking. Some relation curves are gotten as the curve of crack tip opening displacement and loading, or relation between loading and the displacement of loading point for specimen before or after soaking in seawater. The specimen with plastic zone of crack-tip was soaked in seawater for short-term, according to the analysis of experimental results, the length of plastic curve between reloading and displacement is become shorter, and the material is more brittle. In the area of meso-analysis, fracture performance of seawater corrosion steel were investigated by electron microscopic observation, and checked the difference of characteristics parameters and meso-morphologies of material specimen. As to plastic, the effect of seawater on carbon steel dislocation and slip were also researched in the paper. Key Words Carbon steel；seawater corrosion；elasto-plastic fracture；microscopic analysis； bearing capacity of structure with crack 1. Introduction Seawater corrosion affects the mechanical properties of steel, and complex water environment is a source of metal corrosion[1-3]. For the complex corrosion process of Q235 steel in seawater, its behavior shows that the factors of affecting corrosion is including not only the voltage and pH value of them, but also microbial perturbation on the metal surface near[4-5]. The magnetic detection is also effective means to analyze the corrosion. The consequences of corrosion of metallic materials is not only reflected its weight reduction, but also it is the deterioration of bearing capacity and mechanical properties of its structure. So, the stress corrosion and fracture properties of steel is an important investigate field for anti-corrosion and material scientists. 2. Influence of seawater immersion on steel fracture process curve The steel material were made into the test specimen of beam with prefabricated crack, and it were placed on an experiment equipment for the loading of three point bending. As shown in Figure 1, the curve of loading and the displacement of load point are expressed by series of point. For the point of square or triangle, the size of its specimen is that high
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