Dependence of Cold Cracks Formation from the Heat Input when Welding of High Strength Steel with Yield Strength of 500 MPa

Abstract:

The weldability of high strength steel of grade 10G2FBY with a yield strength of 500 MPa is conducted in this paper according to the criterion of cold cracks formation in the seam root of plates with a thickness of 18 and 36 mm. The study was carried out in accordance with GOST 26388-84 on samples of type IX at ambient temperatures from –20 to +20 °С at heat input energy from 5.8 to 14.3 kJ/cm. After welding, the plates were cooled in the air for 24 hours. The main criterion for assessing weldability is the presence or absence of cold cracks after welding. The welding was made with a soft wire 4Y42 with a yield strength of 420 MPa. Cold cracks in high strength steel 10G2FBU for thicknesses of 18 and 36 mm are not detected in heat input over 10.3 kJ/cm by welding at the temperature of +20 °С, at the same time when welding at an ambient temperature of -20 °С cracks are not detected when running over energy of 14.7 kJ/cm. Critical cooling rate in which no cracks appeared was 55 °С/s at the temperature of welding +20 °С, and it was 44 °С/s at a temperature of welding –20 °С for both thicknesses. The criterion HV_max<300 HV is a necessary but insufficient condition for the prevention of cold cracking in steels of the type 10G2FBU. In the conditions of the experiment, cold cracks in the weld seam are absent at a hardness of no more than 250-260 HV, which is probably due to the presence of diffusive hydrogen, which is not regulated in the regulations for the supply of this steel grade

• Periodical: Materials Science Forum (Volume 946)
• Pages: 934-938
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.946.934
• Online since: February 2019
• Authors: M.A. Ivanov*, A.G. Alruhaimi, S.I. Voronin
• Keywords: Cold Cracks, Cooling Rate, Hardness, Heat Input, High Strength Steel, Welding Joint

References

[1] E.L. Makarov, Cool cracks when welding of alloy steels. Moscow, Mashinostroenie, (1981).

[2] GOST 26388-84. Welding joints. Test methods for resistance to formation of cold cracks in fusion welding.

[3] M.A. Ivanov, V.I. Shvetsov, E.L. Volosatova, D.V. Izotov: The development of the theory of crack resistance of castings,, Bulletin Of South Ural State University. Series: Metallurgy. Vol. 17, No 36 (2011) 48-50.

[4] N.N. Prokhorov, Physical Processes in Metals during Welding. 2nd ed. Internal Stress and Deformation. Moscow, Metallurgy, 599 (1976) 4-5.

[5] ASTM, Standard test method for measurement of fatigue crack growth rates, ASTM E 647-08, (2008).

[6] N.P. Aleshina, G.G. Chernyshov, Welding. Cutting. Control: A Handbook. In 2 volumes, Moscow: Mashinostroenie, (2004).

[7] Grivnyak I. Weldability of steels: transl. from Slovak by L.S. Goncharenko; ed.by E.L. Makarov. - Moscow: Mashinostroenie, (1984).

[8] A. Celik, A. Asaran, Mechanical and structural properties of similar and dissimilar steel joints, Mater Character, 43 (1999) 311-318.

DOI: 10.1016/s1044-5803(99)00045-5

[9] T. Terasaki, T. Akiyama, S. Oshita, Study of local hydrogen content related to root cracking. Quarterly Journal of the Japan Welding Society, 4(2) (1986) 378–383.

DOI: 10.2207/qjjws.4.378

[10] British Standard BS EN 1011-2:2001 Incorporating Amendment No.1 Welding. Recommendations for welding of metallic materials. Part 2: Arc welding of ferritic steels. (2001).

DOI: 10.3403/02065964u

[11] A.V. Konovalov, V.M. Nerovny, A.S. Kurkin, Theory of welding processes. Textbook for universities, Moscow State Technical University named after N.E. Bauman, (2007).

[12] V.V. Erofeev, M.V. Shakhmatov, V.G. Krylov, Assessment of the bearing capacity of welded joints with soft layers in the seams, Automatical Welding. 11 (1987) 69-70.

[13] O.A. Bakshi, Yu.I. Anisimov, S.I., Yaroslavtsev, etc., Investigation of the stress-strain state of soft sloping layer by a method of slip lines and finite elements, Kazan: Proceedings of the IV summer school of member countries of the CMEA: Math. Methods in Welding. (1981) 138-143.

[14] K. Satoh, T. Doi, M. Toyoda, Size effect on static tensile properties of Welded joints including of soft interlayers, X Jap. Welding Soc. 37(11) (1968) 242-249.

DOI: 10.2207/qjjws1943.37.1214

[15] Yu. Rabotnov, Mechanics of deformable solids, Moscow: Science, (1988).

[16] M.A. Sholokhov, S.A. Kurkin, S.I. Poloskov, Influence of the shape of cutting on the residual stresses in hull structures of special equipment, Bulletin of Tula State University. Technical Sciences, No. 6. Part 2, (2015).

[17] M.Kh. Shorshorov, T.A. Chernyshova, A.I. Krasovskiy, Testing of metals for weldability, Moscow: Metallurgy, (1972).

[18] N.A. Yuhin, Mechanized arc welding with a melting electrode in shielding gases. (MIG\MAG), (2008).

[19] STO Gazprom 2-2.2-136-2007. Instruction on welding technologies in the construction and repair of field and main gas pipelines. Part I.

[20] A.I. Akulov, G.A. Belchuk, V.P. Demyantsevich, Technology and equipment of fusion welding. Textbook for university students. Moscow, Mashinostroenie, (1977).

[21] GOST 13585-68 Roller test method for determining the permissible modes of arc welding and surfacing.