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

Infrared heating

05.11.2020 13:09:00

Infrared heating by heating panels

Oura equipment for local heat treatment of welded joints can solve any tasks with different heat treatmet modes:

  • high tempering for welding stresses relieving ;
  • preheating before and during welding;
  • austenitization of welded joints and pipe bends;
  • stabilizing annealing of welded joints.

All these tasks are easy to solve by spread heating elements in case, heat treatment of pipes welded joints or other welded constructions is required in fields or in plants.

But ceramic mats use is strongly limited in case of preheating before and during welding of rotating objects. The reason is such heating elements should be mount on to an object and cables can be damaged by rollers or other way during rotating.

Our company has special solution with electric infarared panels or gas heaters to solve such tasks. Heater type depends on Customer.

We provided series of comparative tests to understand process better using special stand with rotators. It allows to rotate tubes and shafts of different lengths and diameters.

Infrared heater test bench

Number of tests with heaters types, their quantity and location were provided to get more information about their influence to welding joint.

Infrared gas heating panels Infrared gas heating panels

We got several important conclusions after tests. First, preheating before and during welding of rotating objects by both these heaters types provides excellent. Preassigned temperature 300-350 degrees reaches if to subject to certain recommendations. Heater type (gas or electrisity) depends on capabilities of a particular company.

Another conclusion is heating speed is important too. For example, if heating is too fast, temperature is uneven axially and radially. this unevenness can be sagnificant.

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