Abstract: A method and apparatus for alloying the surface of a substrate with a suitable alloying material in which the alloying material is placed on the surface of the substrate and a beam of high intensity energy is directed at the alloying material for a predetermined short period of time. The duration of the predetermined short period of time and the intensity of the high intensity beam are cooperatively selected so that the intensity and duration are sufficient to melt the alloying material, and cause alloying of said alloying material with the substrate in a zone contiguous with the surface on which the alloying material has been placed, and yet there is no substantial heating of the body of the substrate below the contiguous zone such that the dissipation of heat from the contiguous zone into the body of the substrate causes rapid solidification of the nowalloyed material and such that dimensional changes as by warping or the like or changes in heat treatment of the body of the substrate are prevented.

Abstract: A method and apparatus for alloying the surface of a substrate with a suitable alloying material in which the alloying material is placed on the surface of the substrate and a beam of high intensity energy is directed at the alloying material for a predetermined short period of time. The duration of the predetermined short period of time and the intensity of the high intensity beam are cooperatively selected so that the intensity and duration are sufficient to melt the alloying material, and cause alloying of said alloying material with the substrate in a zone contiguous with the surface on which the alloying material has been placed, and yet there is no substantial heating of the body of the substrate below the contiguous zone such that the dissipation of heat from the contiguous zone into the body of the substrate causes rapid solidification of the now-alloyed material and such that dimensional changes as by warping or the like or changes in heat treatment of the body of the substrate are prevented.

Abstract: An improved apparatus for alloying a surface of a workpiece of the type in which an electrode, formed of the alloying material, is connected to a pulse generating machine which creates repetitive spark discharges between the electrode and the workpiece when the electrode is in engagement with the workpiece, the improvement being a safety circuit which prevents energization of the electrode until it is engaged with the workpiece.

Abstract: Method and apparatus for forming grooves or slots in a concrete roadway are disclosed. A ribbed sheet of flexible material is positioned on the surface of a freshly poured concrete roadway and the ribs are impressed into the concrete. After the concrete has set and the sheet is removed, a plurality of parallel, skid-resistant grooves are revealed in the roadway. The flexible sheet is placed on and later removed from the roadway by rolling and unrolling it from a spool mounted on a construction vehicle. In one embodiment of the invention, a plurality of small holes are provided in the flexible sheet to aid in the drying of the concrete.