METHOD FOR PROCESSING WELDED JOINTS Russian patent published in 2023 - IPC C21D9/50 C21D1/42 

FIELD: metal working.

SUBSTANCE: invention is related to a method for local low-temperature heat treatment of welded joints in pipes of a main gas pipeline in the field and at extremely low ambient temperatures. The method of processing welded joints includes heating the welded joint zone, holding the welded joint zone at specified temperatures and cooling, and before heating, the welded joint zone is isolated from the effect of the ambient temperature to ensure uniform heat distribution during heating and holding. The heating of the welded joint zone, exposure and cooling of the zone of the welded joint at specified temperatures is carried out by means of an induction heater, and exposure of the zone of the welded joint at a given temperature is carried out in several stages: at the first stage, the exposure of the zone of the welded joint is carried out at a temperature of 250-350°C for 8-12 minutes; at the second stage, the exposure of the welded joint zone is carried out at a temperature of 150-250°C for 8-12 minutes; at the third stage, the exposure of the welded joint zone is carried out at a temperature of 50-150°C for 25-50 minutes; at the fourth stage, the exposure of the welded joint zone is carried out at a temperature of 25-50°C for 8-12 minutes.

EFFECT: expansion of the functionality of methods for processing welded joints due to the possibility of using in the field at low negative ambient temperatures while maintaining high strength characteristics of welded joints and reduced heat treatment time for welded joints.

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