Electron beam surfacing of carbide steels--1. Special features of surfacing technology and preparation of composite surfacing mixtures

摘要

The initial powder of tungsten carbide contains two phases: tungsten monocarbide (99 percent) and W_2C carbide. The TiC powder has a cubic lattice. The phase composition of the initial powder of the high-speed steel is represented by the alpha- and gamma-phases and vanadium carbide (approximately 2 percent).The process of production of the composite sintered material of the type steel R6M5+WC and steel R6M5+WC +TiC is accompanied by interaction between the particles of the powder of high-speed steel and tungsten carbide with the formation of the complex carbide of the type M_6C. The increase of the content of tungsten carbide in the initial mixture from 10 to 40 percent is accompanied by an increase of the fraction of tungsten monocarbide in the sintered material from 0 to 20-25 percent. The steel R6M5+15 percent TiC composite sintered material is characterised by a low-intensity interaction at the interface of the initial phases during sintering. The particles of the high-speed steel are characterised by the precipitation of the carbides VC and M_6C during vacuum sintering. Subsequent cooling with the furnace results in almost the complete gamma->alpha martensitic transformation in the matrix.