METHOD OF HIGH-HEAT TREATMENT OF PIPES Russian patent published in 2004 - IPC

FIELD: petroleum industry; production of high-strength, resistant to a sulfide cracking, chillproof and non-corrodible pipes.

SUBSTANCE: the invention presents a method of a high-heat treatment of pipes, that is dealt with production of the high-strength, resistant to a sulfide cracking, chillproof and non-corrodible pipes of the petroleum range made out of carbonaceous and alloyed with the strong carbide-stabilizing elements (Сг, Mo, V, Nb, etc.) steels. The method of a high-heat treatment of the pipes provides for heating up to the temperature_{Ас3 + 20 - 50°С, hydrocooling by spray in three stages, on the first of which the pipes ate cooled chill with an average speed of 60-85°С/s for 2-4 seconds; on the second stage - with an average speed of 35-50°С/s within 6-8 seconds; on the third stage - with an average speed of 10-15°С/s within 10-13 seconds to the temperature of 100-150°С, and tempering is executed with aggregate exposure of no less than 30 minutes. The invention ensures required martensitic hardenability in pipes made out of the carbonaceous and alloyed steel and excludes probability of warping and a cracking.}

EFFECT: The invention ensures required martencitic hardenability in pipes made out of the carbonaceous and alloyed steel and excludes probability of their warping and a cracking.

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