Investigation of the Initial Corrosion Destruction of a Metal Matrix around Different Non-Metallic Inclusions on Surfaces of Pipeline Steels

Materials

Denis Kuznetsov¹  Andrey Karasev²  Pär G. Jönsson²  Elena Sidorova² 

[1] Department of Functional Nanosystems and Hightemperature Materials, National University of Science and Technology (MISIS), Leninsky Prospect 4, 119049 Moscow, Russia;Department of Materials Science and Engineering, KTH Royal Institute of Technology, Brinellvägen 23, 100 44 Stockholm, Sweden;

关键词: pipeline steels;    non-metallic inclusions;    corrosion;    electrolytic extraction;    chemical extraction;   

DOI  :  10.3390/ma15072530

来源: DOAJ

【 摘 要 】

Typical non-metallic inclusions in two industrial low-carbon steels for oil pipelines were investigated as three-dimensional objects on film filters after electrolytic extraction and filtration of metal samples. A method of soft chemical extraction using a 10%AA electrolyte was used to study the initial corrosion process in the steel matrix surrounding various non-metallic inclusions. To determine and compare “corrosive” inclusions and their influence on the initial stages of corrosion of the adjacent layer of the steel matrix, quantitative parameters (such as the diameter of the corrosion crater (D_cr) and pit (D_pit), and the relative dissolution coefficient of the metal matrix (KD) around various inclusions) were determined after chemical extraction. It was found that CaO-Al₂O₃-MgO oxides and TiN inclusions did not cause an initial corrosion of the steel matrix surrounding these inclusions. However, tensile stresses in the steel matrix occurred around CaS inclusions (or complex inclusions containing a CaS phase), which contributed to the initiation of corrosion around these inclusions.

【 授权许可】

Unknown