The Influence of Boroaluminizing Temperature on Microstructure and Wear Resistance in Low-Carbon Steels

This article investigates the possibility of improving the wear resistance of carbon steel 30 by means of boroaluminizing in treatment pastes. Boroaluminizing was conducted in sodium fluoride (as an activator), boron carbide, and aluminum at furnace heating (the latter two components were taken in a ratio of 4 to 1). The treatment was administered for 4 hours in four temperature modes between 950 degrees C and 1,100 degrees C with a 50 degrees C difference between modes. The microstructure, microhardness, and elemental and phase compositions of the boroaluminized layers were investigated. In addition, the wear resistance of the boroaluminized steels was tested. It was established that treatment temperatures of 1,000 degrees C and lower lead to the formation of layered structures consisting of iron aluminides that are mainly located on top of the diffusion layer and iron borides adjacent to the base metal. Moreover, the use of boroaluminizing temperatures over 1,000 degrees C results in the formation of a heterogeneous structure with iron borides FeB and Fe2B evenly distributed in the matrix of aluminum solid solution in iron. This contributes significantly to the mechanical properties of the layer; in particular, it enhances its wear resistance. It was established that the wear resistance of steel 30 significantly improves after treatment at 1,100 degrees C in comparison with temperature modes of 950 degrees C and 1,000 degrees C.