Применение дуговой сварки при ремонте ковшей экскаваторов в условиях Крайнего Севера

Цель работы – разработка технологии ремонта ковшей экскаваторов ручной дуговой наплавкой в условиях Крайнего Севера. В процессе исследования установлена основная причина выхода их из строя зубьев ковшей, описаны свойства стали 110Г13Л, отражены причины плохой свариваемости стали и меры по снижению сварочных деформаций, подобран оптимальный способ наплавки, сварочное оборудование и наплавочные материалы для работы в условиях низких температур, рассчитаны параметры режима наплавки. В результате исследования разработана технология ремонта ковшей экскаваторов ручной дуговой наплавкой покрытыми электродами в условиях Крайнего Севера.The purpose of the work is to develop a technology for repair of excavators buckets by manual arc welding in the Far North. In the course of the study, the main reason for their failure of the bucket teeth is established, the properties of 110G13L steel are described, the causes of poor weldability of steel and measures to reduce welding deformations are reflected, the optimal method of surfacing, welding equipment and surfacing materials for operation at low temperatures are selected, the parameters of the surfacing mode are calculated. As a result of the study, the technology of repair of excavators buckets by manual arc welding with covered electrodes in the Far North was developed

Mechanical Properties of Temperature Sensitive Microgel/Polyacrylamide Composite Hydrogels—from Soft to Hard Fillers

In this study we investigated the mechanical properties of composite hydrogels based on a polyacrylamide (PAAm) matrix with embedded temperature sensitive poly(N-isopropylacrylamide) (PNiPAM) microgels. We analysed the mechanical properties of the composite material with tensile tests, shear and cavitation rheology. The results of the different experiments displayed an enhancement of mechanical stability with increasing concentration of incorporated microgels. The improved stability is related to an increase of physical cross-linking points due to the incorporation of the microgels. The incorporation of temperature responsive microgel particles introduces temperature sensitive mechanical behaviour of the composite hydrogels. The collapse of the microgels inside the polyacrylamide matrix leads to a change of the volume of the filler particles as well as to a change from a soft filler to a hard filler. The influence of the hard particles on the mechanical stability of the matrix is much stronger which leads to materials with enhanced mechanical properties at high temperatures