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Corrosion Protection of special steels and alloys

#G-533


Development of the Corrosion Protection Technology for Special Steels and Alloys

Tech Area / Field

  • MAT-ALL/High Performance Metals and Alloys/Materials
  • MAT-COM/Composites/Materials
  • MAT-OTH/Other/Materials

Status
3 Approved without Funding

Registration date
21.06.2000

Leading Institute
Institute of Metallurgy, Georgia, Tbilisi

Collaborators

  • University of Idacho / Institute for Materials and Advanced Processes, USA, ID, Moscow\nUniversity of Manchester / School of Materials / Corrosion and Protection Centre, UK, Manchester\nIowa State University / College of Engineering, USA, IA, Ames\nOak Ridge National Laboratory / Physics Division, USA, TN, Oak Ridge

Project summary

The project provides development of technology of corrosion protection of units working in an atmosphere of products of combustion of organic fuel up to 1300°C; creation of materials and means of protection for super oil well pipes and units working at average and moderate temperatures; elaboration of methods of the control of corrosion processes during operating conditions.

The tendency to continuous increase of temperatures caused by development of special areas of new engineering, creates the requirement for constructional materials capable to resist to complex influence of stress fields.

The most heat-resisting are considered chromium base alloys, containing rare-earth metals with high resistance up to 1200°C.

The project stipulates development of thermo-chemical treatment of low alloyed chromium alloys raising their heat resistance via oxide film creation.

The creation of a series of heat resisting chromium alloys capable to work long time in an atmosphere of organic fuel combustion products up to 1300°C and in nitrine environment with working temperatures of the heat-carrier is envisaged. The possibilities of their application for metal-ceramic tight units for high-temperature electrochemical devices and also for manufacturing various zones of fast neutron reactors will be revealed /1,2/.

Nowadays for the production and transportation of petroleum plain carbon and low alloy steels are used which have low corrosion resistance {no more than 0,5-1,5 years, at normative term of operation 10 years} in media of oil wells containing except for petroleum and gas, mineralized hydrogen sulfide water or sulfite reducing bacteria. Closest to above-stated steels from technical point of view is the low carbon low alloyed chromium manganese high strength steel developed in the Institute of Metallurgy of the Georgian Academy of Sciences /3/.However, this steel has propensity to pitting corrosion and shows the lowered corrosion resistance in

hydrochloric acid /4-6/.This lack is supposed to be removed by creation of new steel on its basis by the introduction of alloying elements after deep deoxidization and desulfuration, doping with the micro additives and purging liquid steel in a ladle. The selection of an optimum mode of thermal and high-temperature thermomechanical treatment will allow to create uniform polygonized substructure, which will ensure high mechanical properties and increased resistance to hydrogen embrittlement and sulfide cracking.

For protection against corrosion of main oil pipelines the multi component alloys will be created on the basis of aluminum for metallized coatings and the appropriate coating technology will be elaborated /7-9/.For coatings working at average and moderate temperatures heat resistant low alloyed chromium alloys will be used.

The development of steels and alloys will be carried out with the help of thermodynamic modeling, which will enable to establish chemical composition, to calculate technological parameters of melting, rolling and

heat treatment/10/. Steels and the alloys will be smelted in induction furnaces.

The development of a method and creation of the device for research of the corrosion-electrochemical characteristics of elaborated steels and coatings under thin (50-350 m ) phase layers of electrolytes, simulating various atmospheres is planned.

For the control of corrosion rate of an internal and outside surface of the working pipeline the method based on gauging of polarization resistance will be developed and appropriate gauges and technique of measurement elaborated.

Steel and the alloys will be smelted in induction furnaces.

The structure of the received materials will be studied by methods of optical and electron microscopy, methods of x-ray diffraction and micro-spectral analyses.

The mechanical properties will be investigated by micro hardness, yield and tensile strength, elongation, toughness, porosity and adhesion measurements. Adhesion will be studied with the help of special samples adapted for tensile machine.

Coatings will be applied on standard installations.

The corrosion-electrotechnical investigations will be carried on potentiometer, galvanometer and polarizing resistance measuring device, on the device measuring hydrogen permeability through steel membranes, by defining bending angle of hydrogenated samples at first crack appearance. The resistance to sulfide cracking will be estimated by standard TM.0177-90(NACE) method.

The thermo-chemical treatment alloys will be carried out in an atmosphere of inert gas of the reactionary device, in which specific pressure of oxygen can be adjusted down to 10-24 ATM./8,9/.

The thermodynamic analysis of phase equilibrium and the influence of alloying elements on it will be accomplished by special PC program developed in the Georgian Institute of Metallurgy.

The realization of the project will allow to create of technology of thermochemical treatment of low chromium based and chromium-iron alloys that will increase their heat resistance up to 1300° C; will enable to use them as protective heat resisting coatings; to develop the optimum know-how of tubing and casing pipe preparation technology and couplings to them from the new high-strength steels with enhanced sulfide cracking resistance; as measures of protection of steel the alloys for composite coatings will be developed; for the control of corrosion rate the gauges, devices and techniques for electrochemical characteristic determination of steels and alloys in thin electrolytic films will be developed.

The collective of the scientists participating in the project, has long-term experience in the creation of steels, alloys, metal and non-metal coatings successfully introduced into various industries. The large contribution is brought in by them in standard methods of corrosion investigations and also to development of methods of protection from corrosion of the metal equipment in open-air conditions.

The participants of the project were involved in the 25-year long COMECON program “ Development of corrosion protection measures”. Results of this program were applied on hydroelectric power station ERA-KKW-Nord (GDR) for protection of turbines against corrosion in sea water (with economic benefit of 1500 000 Soviet rubbles). Corrosion tests in above and underneath sea water media were carried out at corrosion stations of the Georgian Institute of Metallurgy in the Batumi bay with its unique climate, which carries character both tropics and subtropics, and in this aspect has no analogues. The developers of the project were the organizers and participants of the international conferences and symposiums. Their works are published in many distinguished editions. The majority of them were weapon scientists.

The realization of the project will enable the scientists of Georgia, including the weapon scientists to bring in the contribution in current main problems of materials science and corrosion. will allow to create additional workplaces and assist conversion processes.


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The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.

 

ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.

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