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Mono-block large-sized plates

#3081


Development of New Methods of Manufacturing Unique Mono-Block Large-Sized Plates

Tech Area / Field

  • FIR-ENG/Reactor Engineering and NPP/Fission Reactors
  • MAN-MPS/Manufacturing, Planning, Processing and Control/Manufacturing Technology

Status
8 Project completed

Registration date
20.07.2004

Completion date
22.09.2006

Senior Project Manager
Alexandrov K A

Leading Institute
NPO Lutch, Russia, Moscow reg., Podolsk

Supporting institutes

  • NIKIMT (Institute of Assembly Technology), Russia, Moscow\nMISIS (Steel and Alloys), Russia, Moscow

Collaborators

  • Midland Metals International Inc., Canada, ON, Toronto

Project summary

Application areas: machine building for power, transport, chemical and mechanical engineering.

The basic tendency of development of modern machine building is increasing specific capacity of stationary and mobile power installations, units of the chemical industry and other unique equipment. This tendency leads to requirement in large billets such as thick large-sized plates. For example, manufacture of the bottoms of modern power nuclear installations demands manufacturing of plates by thickness 265-400 mm with size from 5500x5500 mm up to 8500x8500 mm.

Nowadays manufacture of large-sized plates is carried out by various methods of metal forming and welding. Basically, mono-block plates are manufacturing by rolling or forging. However the existing rolling equipment and technology cannot provide obtaining thick plates in width of 5000 mm and more. The maximal width of a plate during forging process by powerful hydraulic forging presses is limited by the sizes of a press table and size of distance between press columns, i.e. size less than 5000 mm. It is necessary to say that defective metal of an axial zone of an ingot remains in a body in the case of using existing technologies. This defective metal decreases quality of final products.

Manufacturing of large-sized plates by electroslag welding of two or more forged or rolled billet-plates is difficult process with small output, instability of technology and poor quality of the welded plate. The subsequent manufacturing of products from these plates (for example, the bottoms) and welding to installation case (installation block) leads to formation of crossed welded seams, which considerably reduce reliability of work of these products.

The project deals with developing method of producing mono-block large-sized plates with thickness of 265-400 mm with the sizes from 5500 х 5500 mm up to 8500 х 8500 mm. The method includes the following basic technological operations:

1) Manufacturing of tube

1.1.Melting of an ingot of the special cone form;

1.2.Heating; producing cylindrical billet of needed sizes from cone ingot;

1.3.Heating and pressing;

1.4.Cooling of pressed billet for obtaining needed distribution of temperature along billet section and the subsequent insertion by inserter with axial hole for obtaining a tube;

1.5.Heating of a tube; deformation for increasing inner diameter;

1.6.Heating of a tube, deformation for decreasing of wall thickness in several stages;

1.7.Thermal treatment of the tube;

1.8.Mechanical treatment

2) Cutting of the tube wall in parallel of axis.

3) Heating and unwrapping of the tube from cylindrical shape to a plate with hydraulic stamp press by specially developed technological tool.

4) Heat treatment of the tube; the control of the geometrical parameters and structures of metal; a cutting of billet of the required sizes.

5) Punching (stamping) of required products (for example, the bottoms of power installations).

6) Quality control.

The first stage (manufacturing of large-sized tube) demands research and development of new methods of their production, because it is impossible to obtain a thick-walled tube of big diameter by existing methods of tubes manufacture at existing tube-making plants.

The subsequent stages allow manufacturing a mono-block large-sized plate with application of existing forging and stamping hydraulic presses. The basic problem of obtaining such large-sized plates consists in absence of powerful forging presses with the big distances between press columns. The offered technological scheme allows solving this problem. Final processing of products (i.e. unwrapping of the tube from cylindrical shape to a plate) will be carried out with stamping presses. Stamping presses with the big distances between press columns exist at modern plants.

For realization of the developing technological scheme, it is necessary to conduct the big volume of researches: calculations of temperature and deformation modes of processing; structure investigation; researches on prevention of surface defects formation etc. All these researches will be carried out within the framework of performance of the project.

Stages of performance of the project:

1. Investigation of process of an insertion of extreme high billets.

2. Investigation of temperature conditions of heating and cooling of ingots and billets during insertion.

3. Investigation of process of deformation of large-sized holed billets for increasing inner diameter and decreasing wall thickness.

4. Investigation of processes of unwrapping of the tube from cylindrical shape to a plate with hydraulic stamp press by specially developed flat technological tool

5. Investigation of processes of unwrapping of the tube from cylindrical shape to a plate with hydraulic stamp press by specially developed wedge technological tool

6. Investigation of influence of parameters of plastic and thermal treatments on properties and structure of billet metal.

7. Development of technological process of manufacturing large-sized tubes.

8. Development of method of manufacturing of large-sized plates and the bottoms.


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