Peculiarities of loaded low-alloy steel against corrosion-hydrogen degradation in conditions of its contact corrosion

Наведено результати досліджень впливу цинкового та магнієвого протекторів на швидкість корозії сталі 35Х підвищеної міцності, що використовується для виготовлення кріпильних шпильок ко-лони-кипятильника виробництва етилендиаміду. Виходячи з реальних умов експлуатації проведено оцінку ефективності протекторного захисту сталі за механічного навантаження в пружній і пластич-ній областях деформацій та контакту матеріалу шпильок з нержавною сталлю. На основі електро-хімічних досліджень, оцінки кінетики водневого проникнення та експериментів на короткочасну тріщи-ностійкість і корозійне розтріскування встановлено умови можливого наводнювання низьколегованої сталі та чутливості до корозійно-механічного руйнування шпильок при застосуванні в процесії експлуа-тації протекторів.The results of investigation of the zinc and magnesium protectors effect on corrosion rate of the high strength 0.35C-1Cr steel, which is used for manufacturing of boiler column hold studs, are presented. Evalua-tion of the protection effectiveness at conditions of mechanical loading in elastic and plastic ranges of defor-mation and a contact of the stud material with the stainless steel is carried out with taking into account of the service conditions. The conditions of possible hydrogenation of the low alloyed steel and its sensitivity to stress corrosion cracking are determined on the base of electrochemical investigations, kinetics of hydrogen permeation and fracture toughness and stress corrosion cracking test

Activity of key enzymes of antioxidant system in rat blood plasma under the effect of histamine and sodium hypochlorite

The effects of histamine in 1 mg/kg and 8 mg/kg doses that correspond to the doses causing pathological effects at experimental conditions and of sodium hypochlorite in 5 mg/l dose – the lowest concentration of sodium hypochlorite that affects a body by oral administration, on the key enzymes of blood plasma antioxidant system were studied. It was found that histamine used in both concentrations intensified superoxide dismutase activity for 14 days. The simultaneous injections of histamine and sodium hypochlorite caused significant activation of superoxide dismutase in rats. Sodium hypochlorite received by rats with drinking solution caused the same effect. The catalase activity of blood plasma was not significantly affected by histamine, and its activity was significantly increased only under the influence of biogenic amine in 1 mg/kg dose on the 7th day of the experiment. Sodium hypochlorite caused a decline in catalase activity both in intact animals and in animals that received histamine injections subcutaneously. The injection of histamine in 1 mg/kg dose caused an increase in glutathione peroxidase activity on the 1st and 7th day of the experiment. Histamine in 8 mg/kg dose caused the intensification of glutathione peroxidase activity only on the 1st day, followed by the inhibition on the 14th day of the experiment. Sodium hypochlorite received by rats with drin­king solution led to general lowering of glutathione peroxydase activity in blood plasma