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Thermodynamic modeling is performed for regions of phase existence in economically alloyed corrosionresistant steels with the aim of determining the possibility of their use as a bimetal wear-resistant cladding layer. Quantitative evaluation is obtained for the form of nitrogen and oxygen present. It is demonstrated that for steels of the type in question introduction of niobium is only effective at the microalloying level. Keywords: corrosion-resistant steels, hot rolling, alloying with nitrogen, alloying with niobium, niobium carbonitride, austenite stabilization, thermodynamic analysis.Rapid development of high-speed railway transport in Russia requires the creation of reliable transport systems based on using fundamentally new materials with a breakthrough in wear and corrosion resistance indices, operating reliability, endurance, mechanical, and other service properties. In particular, these materials should guarantee accident-free and repair-free operation of superstructures in current railway bridges, whose construction provides a deadweight "trough." Layered materials are most promising for use in its manufacture with a main layer of high-strength structural steels and a cladding layer of multifunctional steel, which apart from high strength and corrosion resistance should exhibit good wear resistance and toughness. These specifi cations are satisfi ed by chromium steels of the transitional austenite-martensite class, which surpass other corrosion-resistant steels both with respect to reliability properties due to the presence of austenite within the structure, exhibiting improved toughness, and with respect to wear resistance due to the fact that residual metastable austenite is capable of undergoing deformation-dynamic martensitic transformation, absorbing mechanical energy and strengthening stressed parts. According to GOST 5632−72, the chromium and nickel contents in corrosion-resistant steels of the austenite-martensite class are within the limits 12-18% and 3.7-8%, respectively, and the content of manganese and silicon is not more than 0.8%. This level of alloying determines the quite high cost of these materials, and therefore for the bimetal cladding layer it is important to develop new economically alloyed austenite-martensite steels. In these steels with a reduced nickel content, the required austenite stability is provided by increasing manganese and nitrogen contents. Use of nitrogen as an alloying element has developed comparatively recently and has made it possible to create a number of new metallic materials with a nitrogen content of more than 0.1% [1][2][3][4].A possible version of the solution presented above may be composites containing 0.05-0.1% carbon, 14-15% chromium, 1.0-2.5% nickel, 2.5-4% manganese, about 0.5% silicon, and 0.1-0.2% nitrogen, with additional alloying by niobium. As seen from Fig. 1, the equivalent content of chromium and nickel for these composites is located in a Schaeffl er structure diagram [5] close to the boundary of structures: austenite + martensite/austenit...

The importance is demonstrated of developing new low-carbon high-strength steels for a marked improvement in both mechanical and service properties of the main metal layer, strength and continuity of joined layers, and also quality characteristics of corrosion-resistant clad rolled product as a whole. In order to resolve this problem on the basis of original methods of physicochemical prediction, a new low-carbon highstrength steel is created of weldable economically alloyed steel, and its main production technology is developed. It is shown that in order to achieve simultaneously high indices of strength (yield strength more than 700 MPa, strength more than 850 MPa), ductility (relative elongation more than 17%), and other steel service properties, nanostructuring is of prime importance, realized with relatively slow metal cooling rates typical for preparing clad rolled product. Keywords: high-strength corrosion-resistant clad rolled product, main layer, high-strength low-carbon microalloyed steels, electroslag surfacing, material layer compatibility, strength, ductility, strength mechanisms, weldability, structural state, excess phase precipitation.New installations of power generation, chemical, petrochemical, coke chemistry, oil processing, and a number of other branches of industry function under conditions of extreme action of corrosive media, high temperature, pressure, variable mechanical and thermal loads, etc. In view of this, readily weldable metal materials are required in order to manufacture their components, exhibiting good corrosion resistance, high strength, ductility, and a number of other properties that are difficult to combine. Realization of a set of the properties listed in monometal material is impossible, especially considering solution of the problem for reducing material and energy consumption, and economic consumption of scarce and expensive alloying elements. Therefore, for these purposes it is promising to use high-strength corrosion-resistant clad steels that are readily weldable. Their high structural strength is provided due to the use of high-strength structural steels as a supporting layer.The range of clad steels produced by electroslag surfacing is quite limited [1]. It includes composites consisting of the main layer (steels St3, 10, 20, 09G2S) with low strength properties (ultimate strength does not exceed 600 N/mm 2 ), clad with corrosion-resistant steel of ferritic (type Kh13) or austenitic (type Kh18N10T) classes. Low strength and, as a conse-

skii, et al., "Properties of weld joints of 02KhSN22S6 corrosionaresistant steel," Avtomat. Svarka, No. 4, 41-44 (1985)o 2. V. Yu. Skul'skii, Technology and Materials for Mechanized Welding of Corrosion-Resistant Steel with a High Silicon Content. Author's Abstract of Candidate Thesis in the Technical Sciences [in Russian], Kiev (1988). 3. V. N. Lipodaev, V. Yu. Skul'skii, and A. L. Belinkii, New Constructional and Welding Materials for Production of Equipment for Production of Concentrated Nitric Acid. Information Letter of the E. O. Paton Institute of Electric Welding of the Academy of Sciences of the Ukrainian SSR [in Russian], No. 16. 4. V. Yu. Skul'skii, V. P. Loginov, V. N~ Lipodaev, et al., ~'Welding of 02Kh8N22S6 steel with accelerated cooling," Avtomat. Svarka, No. 7, 56-59 (1988). 5. V. N. Lipodaev, K. A. Yushchenko, V. Yu. Skul'skii, et al., "Influence of stabilizersand ferrite phase on the corrosion resistance and plasticity of weld joints of austenitic steels with increased silicon content," Avtomat. Svarka, No. 6, 9-12 (1989). EXPERIENCE WITH THE USE OF HIGH-STRENGTH LOW-ALLOY STEELSAt present, reduction of the amount of metal consumed in the manufacture of structures and equipment is a major national-economic problem.One of the realistic ways of solving this problem is the manufacture of welded structures, including equipment and vessels, from high-strength steels.Experience shows that the use of such steels makes it possible to reduce significantly the amount of metal consumed in the manufacture of products.