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Pipeline Hydrotransport Durability

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Development of Plasma Technology for Restoring Worn Surfaces of Hydraulic Transport System Equipment and Determining their Wear Resistance

Tech Area / Field

  • MAN-TRI/Tribology/Manufacturing Technology
  • MAT-ALL/High Performance Metals and Alloys/Materials

Status
3 Approved without Funding

Registration date
01.08.2002

Leading Institute
G. Tsulukidze Mining Institute, Georgia, Tbilisi

Collaborators

  • STI International Associates, USA, CA, San Rafael\nPipeline Systems Incorporated, USA, CA, Concord\nSouth Dakota School of Mines and Technology, USA, SD, Rapid City

Project summary

At the contact of pipeline and hydraulic transport system equipment surfaces with the hydraulic mixture containing solid abrasive particles their hydro-abrasive wear takes place, which is considered a negative phenomenon, requiring realization of a whole complex of measures.

Hydro-abrasive wear is a very complex process, depending on many factors such as: physical-mechanical properties of wearable surface and the solid abrasive matter, causing wear; physical-mechanical properties of carrying liquid medium; hydrodynamic parameters of the flow of hydraulic mixture; granulometric composition of hard abrasive particles; the kind of contiguity of pairs participating in the process of wear and so on. Consequently hydro-abrasive wear is the most complex variety of wear in tribology.

So far there is no universal approach in the field of studying and determining the indices of hydro-abrasive wear, respectively, no establishments of wear resistance of the surfaces, subjected to hydro-abrasive wear. Naturally, there are no theoretical methods, allowing to determine analytically the intensity of hydro-abrasive wear and respectively, the wear resistance of surfaces.

It is obvious that in this case priority should be given to experimental studies, which can give the most reliable results.

The Institute of mining mechanics of the Academy of Sciences of Georgia has been engaged in carrying out fundamental studies in the field of hydro-abrasive wear for over 30 years. In this field the Institute was the leader in the former USSR. A group of well-known scholars in this field in the laboratory of pipeline transport and hydro-mechanization, has developed the methods of studying hydro-abrasive wear, they have built a special original stand for determining relative hydro-abrasive wear. They have developed recommendations on increasing the wear resistance and, consequently, the longevity of equipment and pipelines of hydraulic transport systems. They have initiated studies on restoring and hardening surfaces, subjected to hydro-abrasive wear and establishing their wear resistance. Initial stages of studies showed that from different methods of strengthening and restoring surfaces, subjected to hydro-abrasive wear, the most expedient is the use of plasma technologies (by plasma smelting, plasma spraying), which is a complex process, that depends on many factors, in particular, on the parameters of plasmatrons. In essence they predetermine the quality of restoration and hardening of surfaces and also a change in the physical and mechanical properties of the worn surfaces and materials, used for their restoration. Monographs and many articles (list of the most important publications is applied to the project) are published, in which the results of the executed studies are presented, the branch normative document is developed. Subsequently, due to the disintegration of the USSR studies in this field were stopped and the solution of many questions of a fundamental importance for the problem, has not been completed.

The basic purpose of the present project is the development of plasma technology (plasma hard-facing, plasma spraying, fusion) for restoring the surfaces, subjected to hydro-abrasive wear, for the purpose of achieving maximum wear resistance.

Another purpose is establishing the wear resistance of hydraulic transport system equipment surfaces. This is done basing on determining the rational regimes of plasmatrons for hard-facing, spraying and fusion, allowing shaping the smoothest and most wear-resistant surfaces; and also determining optimum physical and mechanical properties of the restored surfaces, subjected to hydro-abrasive wear.

The third purpose is establishing the laws governing hydro-abrasive wear of hydraulic transport system equipment surfaces, restored by different solid materials and alloys, developing procedures for determining their relative hydro-abrasive wear and, consequently, their longevity.

The problem is extremely urgent, since pressure pipeline hydraulic transport, despite its being the youngest form of transport, in many countries is widely used for the transportation of different solid bulk materials. At present, almost in all developed countries of the world, it successfully functions in many branches of industry and agriculture.

The indisputable advantage of pressure hydraulic transport as compared with other forms of transport are the following factors:

– it can be implemented under any geographical and climatic conditions;


– it is ecologically the cleanest form of transport;
– in most cases it is the most economical;
– its construction and operation does not require large capital investments.

Hydro-abrasive wear is the most harmful phenomenon, which adversely affects the reliability and technical and economic indices of hydraulic transport systems; therefore the development of effective methods and means decreasing hydro-abrasive wear to the minimum, and maximally increasing wear resistance, is a global problem of the branch, since they can substantially increase the longevity and reliability of systems, and also their technical and economic indices. As a result, it is possible to obtain a significant economic effect.

The scientific value of the present project consists in establishing the laws governing hydro-abrasive wear of hydraulic transport system surfaces, restored by different solid materials and alloys and in developing procedures to determine their relative hydro-abrasive wear and also in determining physical and mechanical properties of the restored surfaces.

The technical value of the present project consists in developing the technology of plasma hard-facing, plasma spraying and smelting of the surface, subjected to hydro-abrasive wear; establishing wear resistance of hydraulic transport system equipment surfaces, on the basis of determining rational regimes for hard-facing and spraying, allowing formation of the smoothest and the most wear-resistant surfaces.

The practical and economic value of the present project consists in the fact that the results of studies (like: the rational technology of plasma hard-facing, spraying and smelting, established optimal parameters of plasmatrons, found out the most wear-resistant materials according to hydro-abrasive wear) shall be introduced in the industrial enterprises, by which a significant economic effect will be achieved. The same results will be introduced in the branch normative documents.

To achieve the stated goals it is necessary to solve the problems, listed in the volume of the activity of present project (task 1-6).

The Project completely corresponds to ISTC targets, since in its fulfillment a group of scientists, previously connected with the development of weapons are taking part. The proposed project will give to them the possibility to reorient their abilities and habits to peaceful activity. The project will support the previously conducted studies to peaceful purposes, and encourage the integration of scientists and engineers of the Institute of mining mechanics of the Academy of Sciences of Georgia into international scientific association.

Collaborators are known scientists and specialists in the field of hydraulic transport and science of materials, which represent a large scientific center and association of the USA, able to coordinate and monitor the fulfillment of the project, and if necessary, join these studies.

To achievement the stated goals, the solution of the following problems is provided by this project.

1. Studying the hydro-abrasive wear of surfaces of base metals, from which the hydraulic transport system equipment and the manifolds are prepared.

2. Determining the physical-mechanical (macro-hardness, micro-hardness, ultimate strength) and structural (macro-structure, micro-structure, phase composition, fractography) properties of base metals from which equipment and manifolds, subjected to hydro-abrasive wear, and also restored and reinforced surfaces are prepared.

3. Developing the technology of preparing surfaces subjected to hydro-abrasive wear for plasma hard-facing, spraying and smelting.

4. Developing the procedure of studying relative hydro-abrasive wear and wear resistance on a test bench.

5. Developing the technology of plasma smelting of solid metals and alloys on worn surface.

6. Developing the technology of plasma spraying of hard alloy and metal powders on worn surfaces.

7. Developing the technology of plasma smelting of the surface, which had undergone plasma spraying.

8. Developing the procedure of determining the rational regimes and parameters of plasmatrons for hard-facing, spraying and smelting, that allow shaping the smoothest and the most wear-resistant surfaces, and also determining the optimal physical-mechanical and structural properties of the restored surfaces.

9. Generalizing the results and developing the procedure of determining relative hydro-abrasive wear, and, consequently, the hydraulic transport system equipment and manifold, restored by plasma technology, wear resistance and longevity.

10. Formulation of the corresponding technical documentation.

Experimental studies will be carried out on a special test-bench, developed in the Institute of mining mechanics for determining relative hydro-abrasive wear of surfaces of different materials, the originality (novelty) and usefulness of which is protected by the author's certificate of the USSR.

During the experiments control and measuring equipment, listed in paragraph 9 – Place of realizing of project and equipment - will be used.

The carried out work will make it possible to develop plasma technology, to determine rational regimes of plasmatrons for hard-facing, spraying and smelting, allowing making the smoothest and the most wear- resistant surfaces during their wear in the hydro-abrasive medium. The introduction of the obtained results in industry will make it possible to increase hydraulic transport system equipment and manifold reliability and longevity, to achieve an ecological and economic effect.

The obtained results can have a technical, military-defense and social and economic value.

As a result of the conducted investigations technical documentation will be designed, which, if necessary, will be transmitted to the interested organizations and firms.


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