METHOD FOR SURFACE TREATMENT OF THREADING

摘要

The method of treating load-bearing surfaces of oil field tubes, casings, or the like, particularly surfaces of threads and sealing surfaces of such tubes and casings which will experience a high per-unit area load, comprising the steps of blasting the surfaces for increasing the roughness. thereof in order to obtain a roughness of an average depth of from 7 micrometers to 15 micrometers, by utilization of corundum or silicon carbide at a grain size of from 40 micrometers to 200 micrometers; depositing a synthetic resin varnish onto the blasted surfaces, the varnish curing at a higher than room temperature and including molybdenum sulfide, the varnish being deposited at a layer thickness of from 5 micrometers to 20 micrometers; and curing the deposited varnish by heating.