Microstructure and corrosion properties of p / m fabricated martensitic stainless steel containing nitrogen / Ibrahim Osman El Dieb ; supervised Mohammed Mamdouh Ibrahim , Abdulaziz Fahmy Wahid , Randa Abdulkarim Ahmad

Thesis (M.Sc.) - Cairo University - Faculty Of Engineering - Department Of Metallurgical Engineering

Alloying of stainless steel with nitrogen is useful in increasing strength , wear and corrosion resistance and to decrease additional cost by alloying with nickel as one of the alloying elements , which is considered as a most expensive alloying elementNitrogen is difficult to be dissolved in stainless steel by conventional methodsThe powder of martensitic stainless steel containing 05 nitrogen was prepared by plasma rotating electrode process (PREP) and consolidated by Hot Isostatic pressing process (HIP) In this work specimens of the alloy were solution treated at 1050?C for two hours and water quenched , some of specimens tempered at 370?C , 400?C , 500?C and 600?C for two hours then cooled in the airThe hardness of the solution treated and tempered specimens were measuredThe results showed the highest hardness was obtained for solution treated specimens and the lowest hardness value for specimens tempered at 500?CThe corrosion behavior of the solution treated specimens and solution treated followed by tempering specimens were studied by potentiodynamic technique in two different concentration of sodium chloride solutions , namely 1 in stagnant and stirring conditions in 1NaClThe stirring was at 600 rpm , 900 rpm , and 1200 rpmThe results showed that the highest corrosion rates were for the specimens tempered at 500?C While the lowest corrosion rates were for the specimens : as received , solution treated and specimens tempered at 370?CThe results also showed that as the concentration of the solution increased the corrosion rate values increased , iethe corrosion rate increased in solution 3NaClIn stirring condition , the corrosion rates were increased markedly in case of 600 rpm , and 900 rpmThe solution treated specimens and specimens tempered at 370?C showed the lowest corrosion ratesWeight loss due to corrosion in 3NaCl for solution treated and tempered specimens was studiedThe results showed the highest weight loss value was for specimens tempered at 500?CThe surfaces of corroded specimens were examined using optical microscope

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