Peculiarities of stress corrosion fracture of sensitized and neutron irradiated chromium-nickel austenitic steel

The results of SEM studies of fracture surfaces for the 12Cr18Ni9 austenitic steel ruptured under a fixedtensile load in FeCl3 water solutionand in air are presented. The samples of austenized, sensitized at 650° and irradiated with neutrons (to 1020n/cm2) steel were examined. It was shown thatirradiation hardening and sensitizing annealing increased the susceptibility of steel to intergranular cracking in corrosive solution. Structural features of formation of the strain-induced α’-martensite and its reinforcing effect on fracture in various environments are discussed.

The Influence Factors Study on Acid Corrosion Fracture Conductivity

The influence factors of acid corrosion fracture conductivity included fracture width, acid type and concentration, close pressure, reaction temperature, acid injection rate, et al. The experiment was conducted to study the change of etched fracture conductivity with different acid type and close pressure. The results show that conventional acid tend to produce uniform etched fracture, gelled acid and self-diverting acid prefer to produce non-uniform etched fracture. Besides, conventional acid contributes to improve etched fracture conductivity, gelled acid and self-diverting acid contribute to stabilize fracture conductivity.

High-Strength Bolt Corrosion Fatigue Life Model and Application

The corrosion fatigue performance of high-strength bolt was studied. Based on the fracture mechanics theory and the Gerberich-Chen formula, the high-strength bolt corrosion fracture crack model and the fatigue life model were established. The high-strength bolt crack depth and the fatigue life under corrosion environment were quantitatively analyzed. The factors affecting high-strength bolt corrosion fatigue life were discussed. The result showed that the high-strength bolt corrosion fracture biggest crack depth reduces along with the material yield strength and the applied stress increases. The material yield strength was the major factor. And the high-strength bolt corrosion fatigue life reduced along with the increase of material strength, the applied stress or stress amplitude. The stress amplitude influenced the most, and the material yield strength influenced the least. Low bolt strength and a low stress amplitude level could extend high-strength bolt corrosion fatigue life.

Protection of the working units of agricultural machinery during storage

During the usage and storage agricultural machinery are corrosion fracture. There are many known protective materials to protect against corrosion, which are often expensive. The authors offer a technology of obtaining an anticorrosive material – bituminous composition, that will solve a number of problems: the waste materials recycling and the high cost, lack of protective materials. The bench tests were conducted after determining the optimal content of the bituminous composition. During the year, the known and available protective materials , as well as the newly formed bituminous composition, exposed to atmospheric agents, as provided in the combined storage and in the open air. As a result of a comprehensive evaluation of the protective properties of anti-corrosion materials by method of application on the work surface and the economic feasibility has been proposed a technology of bituminous composition, the protective properties of which were the highest, at the lowest cost .