High-Temperature Gas-Abrasive Wear Resistance Tests of Deposited Alloys

A method and a device for testing materials for resistance to gas-abrasive wear at normal temperatures and temperatures elevated to 1000°C is developed. The test results provide a substantiated choice of surfacing materials for restoring working surfaces of parts of exhaust fans, industrial fans, top-charging gear, gas turbine units, and other equipment. The dependences of the wear of some surfacing alloys on the test temperature, gas-abrasive flow velocity, and the angle of its attack on the sample surface is determined. It is shown that under conditions of high-temperature gas-abrasive wear at small attack angles and increased speed of abrasive particles, it is advisable to use eutectic alloys with a reduced content of expensive carbide-forming elements and carbon, and at high attack angles and low-speed abrasive, heat-resistant and refractory austenitic steels. It is found that the foreign deposited C6.0Cr23Nb7Mo7W2Si2VT alloy, characterized by the highest alloying level and volume fraction of strengthening phases, has the highest resistance to gas-abrasive wear at normal temperatures among those tested. When the test temperature increases to 600°C, its wear resistance decreases by 2.5 times, yielding to the indicator of the experimental C2.8Cr14Ni6Mn6Mo3Ti2Nb2 alloy. The processes of destruction of thin surface layers of alloys are studied using the electron-ion microscopy method, which makes it possible to evaluate the influence of their structural and phase composition on the high-temperature wear mechanism. The study of the wear pattern of the C2.8Cr14Ni6Mn6Mo3Ti2Nb2 alloy showed that under the impact action of the abrasive, cracks are formed in lamellar carbides Me₃C₂ and Me₇C₃, but the high plasticity of nickel-alloyed austenite reduces the likelihood of breakdown of the resulting fragments. At the same time, small carbides (Ti,Nb,Mo)_xC_y and Mo₂C of a compact form restrain the plastic deformation of the austenite-carbide eutectic without destruction.