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

STO 00220368-019-2017

Dear friends!

If you have come to this page, it means that you plan to perform heat treatment in accordance with the standard of organization 00220368-019-2017 "Heat treatment of petrochemical equipment and its components". Or, at least, this regulatory document has drawn your attention

It should be noted that this standard was introduced instead of the standard of organization 00220368-019-2011 from August 1, 2017. This 2011 edition was introduced instead of RTM 26-44-82 "Heat treatment of petrochemical equipment and its elements".

Our company has participated in developing this STO.

Demands for pipelines local PWHT

This regulatory document establishes the requirements and basic technological recommendations for the heat treatment of welded petrochemical, chemical and gas equipment, its elements and assembly units, technological pipelines made of carbon steels, alloy steels, high-alloy corrosion-resistant steels, two-layer and dissimilar steel, as well as alloys on iron and nickel bases.

This standard applies to the development of technological processes, design, manufacture, installation and repair of vessels, devices operating under pressure of not more than 21.0 MPa, vacuum with a residual pressure not lower than 665 Pa (5 mm Hg), without pressure (underfilling) and at wall temperatures not lower than minus 70 ° С, technological pipelines operating under pressure up to 320 MPa, intended for use in technological installations of chemical, petrochemical, oil refining, oil, gas and other industries..

Within the framework of this article, it is not possible to explore all the intricacies and details of this regulatory document. However, we would like to briefly highlight the main differences between the current edition of the standard of organization 2017 and the revised edition of 2011. There are a lot of differences between versions of the document. The main differences are listed below:

  1. For some steel types the parameters of heat treatment modes have been changed. For example, in the standard of organization 00220368-019-2011 for carbon steels of type 3, 20, 20К and two-layer steels on their basis the temperature of stress relieving was set at 600-630 degrees. For low-alloy steels of 09G2S, 16GS types and two-layer steels on their basis the temperature was set at 620-650 degrees. In the standard of organization 00220368-019-2017, these steel grades are combined into one group and the stress relieving temperature for them is set at 580-620 degrees.
  2. The change in heat treatment modes also affected alloy steels and corrosion-resistant steels.
  3. The dwell time for different types of steel has also undergone adjustments.
  4. Particular attention should be paid to the number of thermocouples that must be installed on each welded joint during local powt weld heat treatment.
  5. In the 2011 edition of the standard of organization, one thermocouple could control the temperature of no more than 10 ... 20 m2 of the surface area of the apparatus case during volumetric heat treatment. In the new edition of 2017, there is a remark that with heat treatment of products with an internal volume of more than 1000 m3 and above, having the configuration of a cylinder or sphere with the same thickness of the wall, the area controlled by one thermocouple can be increased to 45m2.
  6. Another distinctive feature of the current version of the standard of organization 2017 from the standard of organization 2011 is that in some difficult cases of heat treatment, it may be necessary to simulate the process of heating the welded joint.

Heat treatment of petrochemical equipment and its elements

It is imposible to discuss all changes in STO 00220368-019-2017 relative to STO 00220368-019-2011 in present short article. All mantioned above changes are shown only for brief acquaintance and can not be used as a recomendations. That is why if you need to perform the jobs based on present STO we recommend to examine the full version of STO 00220368-019-2017.

Whatever regulation document you choose to use during heat treatment of welded joints, all equipment, consumables and accessories can be found in our catalogue.

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