This invention relates to a method and apparatus for surface hardening metals by means of a concentrated beam of electrons. The electron beam is directed and focused to a desired spot on the surface of the said workpiece and is caused to move incrementally from one to the next of a predetermined pattern of points on the work surface. The beam is directed to each point in turn for a predetermined length of time and moved from point to point at a relatively rapid rate. The pattern is projected over the desired surface of the work a predetermined number of times so that the material to be heat treated is brought above the transformation temperature and maintained below the melting temperature by close control of the electron beam parameters. A programmable computer retains in its memory a number of predetermined displacement patterns for the electron beam and controls all the electron beam gun parameters and all machine functions.