Inclusion-induced pitting initiation mechanisms in X70 steel were investigated by scanning electron microscopy, scanning Kelvin probe force microscopy (SKPFM), immersion and electrochemical polarization tests in chloride-containing ion solutions. There are three inclusion types in the X70 steel. Corrosion test results indicated that pitting corrosion resistance of type A inclusion < type C incl...

This paper evaluates the effects of microbiologically influenced corrosion (MIC) on fatigue-crack growth of candidate materials useful in expanding bio-ethanol usage, including a storage-tank steel (ASTM A36) and two pipeline steels (API 5L X52 and X70). The microbiological species sampled and cultivated from an ethanol fuel production stream are responsible for both acetic acid and hydrogen su...

the critical temperatures of a thermomechanical process have a great importance for the final microstructure and mechanical properties of high strength low alloy steels. in this study, the average scheduling was used to determine the critical temperatures of api x70 steel. this steel is extensively used in iran for large diameter, high-pressure gas transportation pipelines as well as the oil tr...

This paper deals with the solid state diffusion bonding of X70 steel to duplex stainless steel. Microstructure and mechanical properties welded dissimilar steels were investigated. Optical microscopy, Electron Backscatter Diffraction, energy dispersive spectrometry, Vickers hardness measurements, X-Ray Diffraction main techniques characterization. Microtructural variation was observed in side c...

Hydrostatic pressure effects on pitting initiation and propagation in X70 steel are investigated by evaluating metastable pitting probability using electrochemical methods and immersion corrosion tests in containing chlorine ion solution. Potentiodynamic tests indicated that hydrostatic pressure can decrease the breakdown potential and lead to a reduced transpassivity region. Metastable test re...

In this paper, the initial and maximum load was studied using Finite Element Modeling (FEM) analysis during impact testing (CVN) of pipeline X70 steel. The Gurson-Tvergaard-Needleman (GTN) constitutive model has been used to simulate growth voids deformation steel at different temperatures. FEM simulations results study sensitivity with GTN parameters values proposed variation Finally, applied ...