FIELD: technological processes.
SUBSTANCE: invention is related to processing of steel parts prior to phosphate chemical conversion treatment. Steel part for conditioning of its surface is treated with water solution that contains tetraborate of alkaline metal and does not contain phosphate ions. Further manganese phosphate is used to perform phosphate chemical conversion treatment of steel part. Steel part with processed surface has chemical conversion coating of manganese phosphate with average diameter of crystalline particles 10-110 micrometer. Invention allows to form phosphate chemical conversion coating that gives to thread connection made of high-chromium steel or of stainless steel with content of Cr of at least 10 weight % resistance to abrasion with no sublayer necessary.
EFFECT: preparation of phosphate chemical conversion coating that gives abrasion resistance to threaded joint.
6 cl, 2 dwg, 7 tbl, 7 ex
