INSTITUTE  OF  PULSE  PROCESSES  AND  TECHNOLOGIES

NATIONAL  ACADEMY  OF  SCIENCE  OF  UKRAINE
© 2012  Institute of pulse processes and technologies NAS of  Ukraine.   All rights reserved.

| Institute's structures | Dept. No 25 | Electrohydropulse treatment (EHPT) of metal structures            
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ELECTROHYDROPULSE TREATMENT (EHPT) OF METAL STRUCTURES
The EHPT technology of is designated to reduce residual stresses in the bulk of metal welded and cast structures by 50-70% with simultaneous stabilization of the dislocation structure.

THE  ESSENCE

Is treatment of concentration areas of residual stresses by pulse load generated by an electrical discharge in water. The treated structure is also immersed in water. The EHPT scheme is given below.

The reduction of macro - and microstresses and stabilization of the dislocation structure occur simultaneously due to activation of dislocation-shear relaxation processes as a result of repeated penetration of stress waves into the treated metal.

The relationship between the pulse action parameters generated by an electrical discharge in water and the changes in the structure and stress-strain state of welded joints of low-alloyed steel is determined, which enables to produce a well-grounded choice of EHPT modes for welded structures of various items, reducing residual stresses in welded joints to the required level.
The proposed technology is implemented using serial installations for cleaning of castings or tailored installations. Depending on the sizes of welded steel structures, EHPT can be carried out either in a special technological tub with water, or with the aid of a treatment chamber moving along the weld joint.
The EHPT technology passed pilot production tests at Dnepropetrovsk Production Association for Production of Heavy Presses (DPA HP) tailored to reducing residual stresses in welded products of dimensions (1,295 x 794 x 245) mm.

Due to aggregate technical and economic performances, the EHPT surpasses all known methods of improving the quality of these metal structures.

Priority for the EHPT technology is owned by IPPT of NAS of Ukraine, no analogues abroad are available.


THE  WELDING  TECHNOLOGY  FOR  DISSIMILAR  METALS  IN  A  SOLID  STATE  USING  THE  METERED HIGHT-INTENSE  ELECTROPULSE  IMPACT  IS  DESCRIBED  ON  THE  NEXT  PAGE  OF  OUR WEBSITE
Technical characteristics
The effectiveness of reducing residual stresses, %
50 - 70
Productivity, rm / h, max
3 - 90
Thickness of elements, mm, no more than
100
Yield point of treated materials, MPa, no more than
500
Energy consumption, kWh / rm
1 - 30
Power consumption, kW · А
100
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Area of a technological section, m  , no more than

80
          Advantages
         
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