FIELD: metal working, namely restoration of cone threaded surfaces of drilling, casing, pump-compressor tubes and equipment in service stations and in field conditions. SUBSTANCE: tool for restoring cone threads of oil production tubes includes threaded working surface reciprocal to worked thread with grooves arranged on working surface and crossing direction of threads. Strengthened wear resistant layer is applied onto working surface of tool. Novelty is coating applied in the form of stripes on front, rear contact surfaces of thread, on its apexes and recesses. Width S of coating stripes is no less than 2 mm. Coating stripe is applied at least at one side of each groove in accordance with starts of threads at screwing off tool with reciprocal threaded surface. Thickness of coating is determined by given dependance δ = P•tgϕ/n+δmcos(1*/π•1), where parameters: P- cone thread pitch, ϕ - inclination angle, l* - length of cone thread until main plane are limited by standard values; n - number of grooves, δm- wear degree of thread along its mean diameter calculated by statistic averaging of cone threads subjected to restoration; l - current coordinate along thread generatrix measured from mean point of generatrix. Front contact surfaces of thread are coated by material having maximum antifriction properties and abrasive wear resistance. Rear contact surfaces of thread, its apexes and recesses are coated by material with minimum tendency to adhesion and diffusion bonding with worked material. In addition coating is applied in the from of stripes whose width is no less than height of thread profile on flat surfaces of grooves adjoining to thread coating. Grooves are coated with material whose wear resistance is less than that of material used for coating contact surfaces of thread, its apexes and recesses. Tool for restoring threaded surfaces of couplings is in the form of screw tap. Tool for restoring threaded surfaces of tubes is in the form of threading die. EFFECT: enhanced strength of tool, high quality of restored threads. 5 cl, 3 dwg
