METHOD FOR ELECTRIC SPARK COAT APPLYING, MAINLY ON CONTACT SURFACES OF MEASURING TOOL FOR WORKING THREADS Russian patent published in 1999 - IPC

FIELD: strengthening and(or) restoring properties and(or) dimensions of thread working tools. SUBSTANCE: method comprises steps of relatively moving electrode-anode and worked tool-cathode; realizing relative oscillation with sonic and ultrasonic frequencies in directions normal and parallel relative to worked surface; imparting low-frequency vibration to electrode-anode; imparting ultrasonic oscillations with amplitude no less than 5 micrometers to tool-cathode; applying coat onto front contact surfaces of thread of tool-cathode after increasing by 30-40% value of discharging current and amplitudes of ultrasonic oscillations relative to values of electric current and amplitude at working rear contact surfaces; imparting additional ultrasonic oscillations to electrode-anode. EFFECT: enhanced fatigue strength, wear resistance and increased useful life of tool due to formation of intermetallic compounds in layer of coating and in layers of tool material abutting to it. 3 cl, 4 ex