EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS
DOI:
https://doi.org/10.15802/stp2015/38255Keywords:
complex-alloyed cast iron, the critical point, chromium, vanadium, vanadium carbides, pearlite, austenite, phase transformationAbstract
Purpose. Pearlite is not accepted in the microstructure of wear resistant steels and cast irons. To prevent the pearlite by means of appropriate selection of mode of quenching requires the knowledge of the temperature of the critical points Ac1 and Ac3 for various steels and cast irons. Purpose of work is determine the effect of V (5-10%) and Cr (up to 9%) on the temperature range of the phase-structural transformation "pearlite®austenite in the complex-alloyed V-Cr-Mn-Ni white cast irons with spheroidal vanadium carbides. Methodology. Nine Mg-treated cast irons smelted in laboratory furnace were used for investigation. The metallographic and optical dilatometric analysis methods as well as energy-dispersive spectroscopy were used. Findings. It is shown that in irons studied the critical point Ac1 is in a temperature range from 710-780 °C (lower limit) up to 730-850 °C (upper limit). The data on the concentrations of chromium and vanadium in a matrix of iron are presented, the regression equation describing the effect of vanadium and chromium on the temperature limits of the transformation «pearlite ® austenite» are obtained. Originality. It is shown that increase the chromium content leads to growth of lower and upper limits of the temperature interval of transformation "pearlite ® austenite"; vanadium increases only the upper limit of the range. It was found that the effect of chromium on the critical point Ac1 is attributed to its solubility in the metallic matrix (concentration of Cr in the austenite reaches 7%); vanadium, due to its slight dissolution in the matrix (vanadium content does not exceed 1.75%), affects the critical point indirectly by increasing of chromium concentration in the matrix due to enhanced carbon sequestration in VC carbides. Practical value. The temperature ranges of heating for quenching of V-Cr-Mn-Ni cast irons with spheroidal vanadium carbides, which provides the formation of austenitic-martensitic matrix without pearlite, is transformation proposed.
References
Vakulenko I.A., Bolshakov V.I. Morfologiya struktury i deformatsionnoye uprochneniye stali [The morphology and structure of work hardening steel]. Dnepropetrovsk, Makovetskiy Publ., 2008. 196 p.
Silman G.I., Pamfilov Ya.A., Gryadunov S.S. Vliyaniye struktury belykh khromovanadiyevykh chugunov na ikh iznosostoykost [The effect of structure of white chromium-vanadium cast irons on their wear resistance]. Metallovedeniye i termicheskaya obrabotka metallov – Metal Science and Heat Treatment of Metals, 2007, no. 8, pp. 32-35.
Zhukov A.A, Silman G.I., Froltsov M.S. Iznosostoykiye otlivki iz kompleksno-legirovannykh belykh chugunov [Wear resistant foundry out of complex-alloyed white cast irons].Moscow, Mashinostroeniye Publ., 1984. 104 p.
Efremenko V.G., Chabak Yu. G., K. Shimidzu. K vyboru tekhnologicheskoy skhemy smyagchayushchey termicheskoy obrabotki vysokokhromistogo chuguna [About the choice of technological mode of softening heat treatment of high chromium cast iron]. Nauka ta prohres transportu. Visnyk Dnipropetrovskoho natsionalnoho universytetu zaliznychnoho transportu − Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, 2014, no. 2 (50), pp. 103-110.
Tsypin I.I. Belyye iznosostoykiye chuguny [Wear resistant white cast irons].Moscow, Metallurgiya Publ., 1983. 176 p.
Tsypin I.I. Belyye iznosostoykiye chuguny – evolyutsiya i perespektivy [Wear resistant white cast irons – Evolution and Prospects]. Liteynoye proizvodstvo – Foundry, 2000, no. 9, pp. 15-16.
Chabak Yu.G., Efremenko V.G., Stanishevskiy R.R. Strukturnyye izmeneniya v kompleksnolegirovannom belom chugune pri destabiliziruyushchem nagreve [Structural changes in the complex-doped white iron at destabilizing heating]. Visnyk Dnipropetrovskoho natsionalnoho universytetu zaliznychnoho transportu imeni akademika V. Lazariana [Bulletin of Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan], 2009, issue 38, pp. 229-232.
Cheylyakh A.P. Ekonomnolegirovannyye metastabilnyye splavy i uprochnyayushchiye tekhnologii [Economic metastable alloys and hardening technology]. Kharkov, NNTs KhFTI Publ., 2003. 212 p.
Chaochang W., Hsu H.T., Qian M. Formation of Spheroidal Carbide in Vanadium White Cast Iron by RE Modification. Material Science Technology, 1990, vol. 6, pp. 905-910. – doi: 10.1179/mst.1990.6.9.905
De Mello J.D.B., Duran-Charre M., Hamar-Thibualt S. Solidification and solid state transformations during cooling of chromium-molybdenum white cast irons. Metallurgical Transactions A, 1983, vol. 9, no. 14, pp. 793-801. – doi: 10.1007/bf02645549
Xinba Y., ShimizuK., Matsumoto H., Kitsudo T., Momono T. Erosive Wear Characteristics of Spheroidal Carbides Cast Iron. Wear, 2008, vol. 264, pp. 247-257. – doi: 10.1016/j.wear.2007.07.002
Shimizu K., Naruse T., Xinba Y., Kimura K., Minami K., Matsumoto H. Erosive wear Properties of High V-Cr-Ni Stainless Spheroidal Carbides Cast Iron at High Temperature. Wear, 2009, vol. 267, pp. 104-109. – doi: 10.1016/j.wear.2008.12.086
Shimizu K., Naruse T., Xinba Y., Teramachi H., Araya S. Ishida M. High Temperature Erosion Behaviors of High V-Cr-Ni Spheroidal Carbides Cast Iron. Key Engineering Materials, 2011, vol. 457, pp. 255-260. – doi: 10.4028/www.scientific.net/kem.457.255
Li D., Liu L., Zhang Yu. Phase diagram calculation of high chromium cast irons and influence of its chemical composition. Materials and Design, 2009, vol. 30, pp. 340-345. – doi: 10.1016/j.matdes.2008.04.061
Shigenori N., Tadasi K., Hideto M. Influence of Mg-Treatment Condition on Morphology of Vanadium-Carbide in Stainless Spheroidal Carbide Cast Iron. Journal of Japan Foundry Engineering Society, 2008, vol. 80 (1), pp. 3-7.
Yoneta N., ShimizuK., Hara H., Tanaka M., Nawa Y. Wear Characteristics of Spheroidal Carbides Cast Irons in Uniaxial Rotary Glass Shredder. Key Engineering Materials, 2011, vol. 457, pp. 249-254. – doi: 10.4028/www.scientific.net/kem.457.249
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