Plasma-Arc Cutting and Surface Hardening
Development of Ecologically Pure Technology of Plasma-Arc Cutting of Metals and Surface Hardening without Melting of Surface in the Environment of Water Vapor
Tech Area / Field
- MAT-SYN/Materials Synthesis and Processing/Materials
3 Approved without Funding
Georgian Technical University, Georgia, Tbilisi
- Eindhoven University of Technology, The Netherlands, Eindhoven
Project summaryIn connection with high efficiency, accuracy of cut out details and profitability, currently it is widely applied air-plasma cutting devices. However, there are problems, solution of which in order to develop plasma techniques and technology have special value. Particularly, during air-plasma cutting process is accompanied by allocation in an environment of harmful substances in the big concentration at the sometime saturation of edges by nitrogen and oxygen, negatively influences on the quality of welded seams at the subsequent welding processes of previously cut out blanks. Metal on welded edges is characterized by change of chemical and phase structure and also with high value of hardness, etc.
The solution of the mentioned problems and in order to increase efficiency of process in many cases depends on correct choice of plasma generating environment. Water vapor environment can satisfy all requirements given to plasma generating gas.
The offered project have multipurpose sense, where the major is elaboration of non-polluting cutting process of ferrous as well nonferrous materials by plasma arch operating in water vapor environment. As the accompany effects of the project are - increase of quality of surfaces of cut edges, expansion of technological opportunities of a plasma arch and development of design in order to increase life cycle of plasmatrones.
Currently we carried out research works and studied electrical and energetic characteristics of plasma arch, working on water vapor in a range of the electrical current from 100 A up to 200 A. In the environment of water vapor the effectiveness of thermal capacity of an arch on 26-30 % and effective efficiency on 10-15 % more in comparison with an arch working by compressed air are ascertained. At the same time the ecological parameters of the process are improved on 50-60 %. Actually that this parameter can be increased up to 80-90 % that will allow excluding utilization of expensive ventilating devices at the enterprises.
Based on carried out research works quality of edges for low-carbon steel has been investigated. Results of research have shown that micro hardness of a surface of edge has decreased almost twice, saturation of edges with nitrogen 2-3 times, and oxygen 1,5-1,6 times.
In the Georgian Technical University we have started usage of water vapor for plasma superficial hardening, without burning-of surfaces of the processed metal. The first series of experiments has yielded positive results that allow us to think about of continuation of researches in this field.
In the case of positive solution of implementation of items of the mentioned project, the technology of plasma cutting and as well the strengthening of metal’s surface would change widely used plasma technologies based on compressed air. It is supposed to conduct the following investigations:
- Determination of electrical and power characteristics of a plasma arch in a range of current from 100A up to 500A;
- Determination of Ecological characteristics;
- Determination of technological parameters of cutting and hardenings as well;
- Metalografy of cut edges, welded seams and the strengthened surfaces;
- Determination of Influences of water vapor’s temperature on characteristics of an arch;
- Design of plasmatrons with the increased resource of work;
- Design and implementation of the small-sized power supply;
- Design and implementation of compact steam generator;
- In order to determine the optimum sizes of basic units (swirler, nozzle, etc) of the plasmotron will be carrying out of theoretical investigations in the field of gas dynamics.
Qualification of persons participating in the project corresponds to a high level that guarantees successful carrying out of research and development of the project.