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2020 №06 (03) DOI of Article
10.37434/tpwj2020.06.04
2020 №06 (05)


The Paton Welding Journal, 2020, #6, 20-26 pages
 

Influence of low-temperature tempering on structure and properties of welded joints of high-strength steel 30Kh2N2MF

O.A. Gaivoronskyi, V.D. Poznyakov, O.M. Berdnikova, T.O. Alekseenko and O.S. Shyshkevych


E.O. Paton Electric Welding Institute of the NAS of Ukraine 11 Kazymyr Malevych Str., 03150, Kyiv, Ukraine. E-mail: office@paton.kiev.ua

Abstract
The results of investigations of influence of low-temperature tempering on structural changes, physical and mechanical properties of HAZ metal and crack resistance of welded joints of high-strength medium-carbon alloy steel 30Kh2N2MF are given. It is shown that the use of a low-temperature tempering is absolutely necessary during welding of products by low-alloy materials, which significantly increases the crack resistance of welded joints. During welding of joints by high-alloy materials in the hardened HAZ metal a relatively more ductile and less stressed structure is formed, in which the maximum level of stresses is lower than that which can be achieved after thermal tempering of a welded joint with a low-alloy weld. Therefore, the level of crack resistance of welded joints is sufficiently high in any case and in this situation there is no need to use low-temperature tempering. This is an unnecessary technological operation that does not significantly affect the reliability during operation of products, but only makes their cost higher. 13 Ref., 4 Tables, 6 Figures.
Keywords: high-strength steel, welded joints, low-temperature tempering, structure, properties, crack resistance

Received 12.05.2020

References

1. Bernshtejn, M.L. (1968) Thermomechanical treatment of metals and alloys. In: 2 Vol. Moscow, Metallurgiya [in Russian].
2. Lakhtin, Yu.M. (1983) Metal science and heat treatment of metals. Moscow, Metallurgiya [in Russian].
3. Fillipov, G.A., Sarrak, V.I. (1980) Local distribution of hydrogen and internal microstresses in structure of hardened steel. Fizika Metallov i Materialovedenie, 49, 121–125 [in Russian].
4. Grabin, V.F., Denisenko, A.V. (1978) Metal science of lowand medium-alloyed steels. Kiev, Naukova Dumka [in Russian].
5. Efimenko, M.G., Radzivilova, N.O. (2003) Metal science and heat treatment of welded joints. Kharkiv, NTU KhPI [in Ukrainian].
6. Anokhov, A.E., Korolkov, P.M. (2006) Welding and heat treatment in power engineering. Kyiv, Ekotekhnologiya [in Russian].
7. Makarov, E.L. (1981) Cold cracks in welding of alloyed steels. Moscow, Mashinostroenie [in Russian].
8. Gordonny, V.G., Gajvoronsky, A.A., Sargevsky, V.A., Lebedev, Yu.M. (1992) Influence of type of weld metal on structure, properties and resistance of joints of high-strength hardening steels to cold cracking. Avtomatich. Svarka, 11−12, 13–16 [in Russian].
9. Kozlov, R.A. (1969) Hydrogen in welding of hull plate. Leningrad, Sudostroenie [in Russian].
10. Poznyakov, V.A., Kostin, V.A., Gajvoronsky, A.A. et al. (2015) Effect of welding thermal cycle on structure-phase transformations and properties of HAZ metal of alloyed 30Kh2N2MF type medium-carbon steel. The Paton Welding J., 2, 7-13. https://doi.org/10.15407/tpwj2015.02.02
11. (1972) New methods for evaluation of brittle fracture resistance of metals. Ed. by Yu.N. Robotnov. Moscow, Mir [in Russian].
12. (1990) Strength of welded joints under alternating loads. Ed. by V.I. Trufyakov. Kiev, Naukova Dumka [in Russian].
13. Markashova, L.I., Grigorenko, G.M., Poznyakov, V.D. et al. (2009) Structural criterion for evaluation of strength, ductility, crack resistance of metals, alloys, composite materials and their welded joints. In: Proc. of 4th Int. Conf. on Fracture