Equipment for local and volumetric PWHT (heat treatment of welded joints)

GOST 32569-2013

Actual standart gives main technical requirements to technological pipes: circs for selection and use of pipes, pipeline parts, fittings and basic materials for their manufacture, and requirements for welding and heat treatment, location, conditions for their exploitaionl, which are important for observation by manufactures, having production controlled by supervisory authorities.

Standart is intended for specialists, who design, build and reconstruct pipes of oil refining, chemical, petrochemical, oil, gas and other related industries.

Heat treatment requirements for welded pipes joints governed by 12.2 paragraph.

In particular, this paragraph states:

Both general furnace and local heating can be used for heat treatment of welded joints with any method, providing simultaneous and uniform heating of welded joint and flank surfaces from both sides of main metal from all perimeter. Minimal wedth of heating surface up to required temperature should be more then double tube width to each side from joint, but more then 50 mm.

Tube parts, located close to heating joint during heat treatment, should be covered by thermal insulation for smooth temperature change along.

Flame heating for chromium-nickel austenitic steel pipes is forbidden without referense to its work pressure.

Special conditions shoukd be followed during heat treatment. They provide ability for free thermal expansion and prevent plastic deformation.

Heat treatment of welded joints should be provided without interruptions. For emergency stop (electicity break, for example), slow сooling should be provided down to 300°С. in case of repeat heating, heating time of welded joint should be summarized with primal heating time.

Heating modes, dwell and cooling for heat treatment of pipes and other elements should be recordered by special devices.

Heat treatment of ona joints should be provided not more then 3 time. quantity of temper heat treatments is not limited.

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