Modification of metal surfaces by means of a high-velocity plasma

The effects of gas jets generated by tubular high-explosive charges on the inner surfaces of cylindrical parts made from various metals are investigated experimentally. It is shown that by varying the geometrical dimensions of the charges it is possible to significantly alter the degree of hardening of the surfaces of parts made from different steels (including tool steel) and titanium and also to modify the thickness of the hardened layer. The microhardness of the surface layers is plotted as a function of the parameters of the gas jet. The nitrogen and carbon contents of the modified layers are measured. The influence of the initial roughness of the surfaces is investigated, and the downstream transport of testpiece material is recorded. A severalfold increase in the content of nitrogen and carbon in the modified layers is recorded by two independent methods.