Search academic texts

Information × Registration Number 0215U000347, 0114U000821 , R & D reports Title Increasing fretting resistance of fasteners from VT22 titanium alloy by forming of functional coatings by means of heat treatment popup.stage_title Head Fedirko Victor, Registration Date 18-02-2015 Organization Karpenko Physico-Mechanical Institute of the National Academy of Science of Ukraine popup.description2 As a result, the project developed and proposed flow sheet of the surface modification (oxy-nitriding) of hot-heading bolts of VT22 alloy combined with aging in a single process cycle to increase their fretting fatigue and ensure a balance of strength, fatigue, tribological and corrosion performance. It is shown that the application of the proposed technology for surface modification (oxy-nitriding) of hot-heading bolts of VT22 alloy, allows getting the following parameters of the modified layer: surface hardness of 5.2 GPa ... 6.5, the depth of hardened zone 25 ... 30 micron, thickness of the film 0.03 ... 0, 05 micron. It is shown that the oxy-nitride layer and application of the antifriction coating VAP-2 of VT22 alloy samples less reduce the durability of the samples in fretting fatigue test than with the rotation bending. According to the results of bench, testing on the "Antonov" public enterprise, of the experimental batch of hot-heading bolts of VT22 alloy found that the destruction of bolts influenced process flow factors: thread rolling and aging. So two times greater durability under cyclic tensile test shown the bolts which was rolling after aging, combined with oxy-nitriding. In addition to durability, thread-rolling technology factor affected the location of the fracture. That is, in the case of thread rolling before aging bolts was destroyed on thread, and if the thread-rolling was performed after aging - bolts was destroyed by fillet connections under the head. It was found that the cause of the accelerated destruction was small cracks that formed because of thread rolling. To improve the quality of thread rolling was proposed technological solutions of its implementation.5481 Product Description popup.authors Кравчишин Тарас Миронович Лук'яненко Олександр Геннадійович Труш Василь Степанович popup.nrat_date 2020-04-02 Close