FIELD: abrasive-air treatment of metallic articles such as pump-compressor tubes.
SUBSTANCE: method comprises steps of rotating tube around lengthwise axis and supplying onto outer surface of its cone threaded portion abrasive-air jet; imparting to said jet rectangular cross section and arranging its wide side along tube axis; feeding jet along thread recesses and directing in such a way that its central plane is parallel to generatrix of cone surface of thread and is arranged in zone between apexes and recesses pf thread profile and its axis is inclined relative to plane of tube cross section by angle equal to lead angle of thread; forming jet in such a way that its thickness in working zone is equal to 1.2 - 1.7 of height of profile of worked thread. Apparatus for performing the method includes fluid-tight working chamber having opening for inlet and outlet of tube and unit for forming air-abrasive mixture in the form of hollow body provided with diffuser and through pipelines communicated with abrasive metering feeder and with compressed gas source. Hollow body is arranged in working chamber; it is provided in addition with super-sound nozzle mounted in its cavity with gap and it is restricted by base in the form of hollow cylinder half and by two profiled plates secured to base. Diffuser is joined to hollow body, it is arranged in front of working port of flat nozzle and formed by means of two flat plates defining rectangular flow-through cross section. Hollow body is communicated with metering feeder of abrasive material; flat nozzle is communicated with compressed air source. Relation of surface area of critical section of nozzle to surface area of its outlet section may be in range 0.24 - 0.60. Diffuser is spaced from nozzle by distance consisting 0.5 -2.0 of height of outlet cross section of nozzle. Surface area of outlet cross section of diffuser consists 1.1 - 1.4 of surface area of outlet cross section of nozzle.
EFFECT: rational use of abrasive material, enhanced quality of cleaning tube.
5 cl, 10 dwg
