DOI: 10.18503/1995-2732-2021-19-2-32-39
Abstract
Problem statement (relevance of the research). When manufacturing castings of pipeline valve body parts from corrosion-resistant steel grade 12Kh18N9TL within the GOST limits, there is instability of its mechanical properties and the lack of homogeneity of the structure (a ferritic phase in the structure amounting to 20%), resulting in a decrease in the intergranular corrosion resistance and performance properties. The research paper analyzes the influence of the chemical composition of steel grade 12Kh18N9TL on the mechanical properties and the content of the ferritic phase using a statistical analysis. It is noted that the mechanical properties and the ferrite content of the steel grade under study significantly vary depending on the chemical composition of steel within the GOST limits. The optimal properties and performance characteristics of the castings made of the steel grade under study are achieved, when the content of the ferritic phase doesn’t exceed 5%. Therefore, improving the mechanical properties stability and the structure of critical duty castings made of austenitic steel grade 12Kh18N9TL is the most important issue, and the solution of this problem requires the chemical composition optimization. Methods applied. To determine the nature and rate of the influence of the chemical composition on the mechanical properties and the content of the ferritic phase, the correlation and regression analysis was used. The chemical composition of steel grade 12Kh18N9TL was optimized by the steepest ascent method. Originality. We designed the mathematical models that predict the mechanical properties and the content of the ferritic phase for the given chemical composition. Result. We compared the matching and partial correlation coefficients of the influence of the chemical composition on the mechanical properties and the ferrite content of steel. Graphical diagrams were built to show the influence of the titanium and aluminum ratio on the mechanical properties and the content of the ferritic phase. Practical relevance. The chemical composition of corrosion-resistant austenitic steel has been optimized within the GOST limits to provide the required content of the ferritic phase. The results of the research may be valuable for manufacturing castings from corrosion resistant steel 12Kh18N9TL.
Keywords
Chemical composition, corrosion-resistant steel, casting, ferritic phase, correlation and regression analysis.
For citation
Ganeev A.A., Ramazanov A.K. Optimization of a Chemical Composition of Corrosion-Resistant Steel 12KH18N9TL for Pipeline Valve Castings. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2021, vol. 19, no. 2, pp. 32–39. https://doi.org/10.18503/1995-2732-2021-19-2-32-39
1. Lutsenko V.A., Golubenko T.N., Lutsenko O.V., Kozachek A.S., Glazunova N.A. The impact of chemical composition on mechanical properties of the alloyed steel. Litiyo i Metallurgiya [Foundry Production and Metallurgy], 2018, no. 1, pp. 120–123. (In Russ.)
2. Ramazanov A.K., Ganeev A.A. Features of casting pipeline valve body parts made of corrosion-resistant steel 12Kh18N9TL. Vestnik Magnitogorskogo gosudarstvennogo tekhnicheskogo universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University], 2020, vol. 18, no. 2, pp. 22–29. (In Russ.)
3. Nekhendzi Yu. A. Some issues on the theory of alloying of special cast high alloys. Liteynoe proizvodstvo [Foundry], 1958, no. 10, p. 23. (In Russ.)
4. Guiding document RD 38.13.004-86. Operation and Repair of Process Pipelines Operating Under Pressure up to 10.0 MPa (100 kgf/square centimeter).
5. Vasilevsky P.F. Tekhnologiya stalnogo litya [Technology of steel castings]. Moscow: Mechanical engineering, 1974, 408 p. (In Russ.)
6. ST TsKBA 005.3-2009. Pipeline fittings. Metals used in production of fittings. Part 3. Foreign materials and their domestic equivalents. ZAO NPF TsKBA, 2009, 61 p.
7. Mainak Saha. Study of austenitic stainless steel castings. Volume 14, Issue 3 Ver. III (May - June 2017), pp. 01–06.
8. Marcelo Aquino Martorano, Caio Fazzioli Tavares and Angelo Fernando Padilha. Predicting delta ferrite content in stainless steel castings. ISIJ International, vol. 52 (2012), no. 6, pp. 1054–1065.
9. Angelo Fernando Padilha; Caio Fazzioli Tavares; Marcelo Aquino Martorano. Delta ferrite formation in austenitic stainless steel castings. Materials Science Forum, vols. 730–732 (2013), pp. 733–738.
10. Parrens C., Dupain J.-L., Malard B., Poquillon D. Aging effect on creep properties of type 310 austenitic stainless steel during isothermal and non-isothermal creep tests at 870°C. Experiments and modeling. Creep and Fracture of Engineering, pp.132–133. Materials and Structures (Creep2017): Proceedings of the 14th International Conference on Creep and Fracture of Engineering Materials and Structures. June 19-21, 2017. St. Petersburg: Polytechnical Publishing House, 2017, 170 p.
11. R. Prakash Kolli, Sarah Mburu, Daniel E. Perea, Jia Liu, Samuel C. Schwarm, Arielle Eaton, Sreeramamurthy Ankem. Characterization of element partitioning at the austenite/ferrite interface of as cast CF-3 and CF-8 duplex stainless steels. Microscopy and Microanalysis, volume 21, supplement S3: Proceedings of Microscopy & Microanalysis 2015, August 2015, pp. 365–366.
12. Borovikov V. Statistica. Iskusstvo analiza dannykh na kompyutere [Statistica. The art on computer analysis of data]. Saint Petersburg: Piter, 2003, 688 p. (In Russ.)
13. Oyuntsetseg C., Batmunkh B., Munkhtuya C. The study of the properties of the casting stainless steels. Materialy VI Mezhdunarodnoy konferentsii Problemy mekhaniki sovremennykh mashin [Proceedings of the 6th International Scientific Conference Issues on Mechanics of Modern Machines], The Ministry of Education and Science of the Russian Federation, Wuhan Textile University (PRC). Ulan-Ude: Publishing Department of East Siberia State University of Technology and Management, 2015, vol. 2, pp. 242–248. (In Russ.)
14. Khimushin F.F. Nerzhaveyushchie stali [Stainless steels]. Moscow: Metallurgy, 1967, 800 p. (In Russ.)
15. Kremer M.A. Fasonnoe litie iz nerzhaveyushchey i kislotostoykoy stali [Shaped castings made of stainless and acid-resistant steel]. Moscow, 1961, 74 p. (In Russ.)
16. Efimychev Yu.I., Mikhailov S.K., Svyatkin B.K., Prokhorov I.I. Regressionny analiz kachestva staley i splavov [Regression analysis of the quality of steels and alloys]. Moscow: Metallurgy, 1976, 224 p. (In Russ.)