Microstructural Characterization of Joints of Maraging 300 Steel Welded by Laser and Subjected to Plasma Nitriding Treatment

Abstract:

Amongst the ultra high strength steels, the maraging steels have been noticed because they maintain the fracture toughness superior to other steels of their class. The main difference is the way they acquire resistance. While the conventional carbon steels raise their resistance by heat treatments forming harder phases such as martensite or bainitic constituents, the maraging steels harden by intermetallic particles precipitation. These steels are very promising for several applications, mainly for the aerospace or nuclear areas. In this work, tests of laser welding on a sample of maraging 300 steel, have been carried out, by applying aging at several times and temperatures and analyzing the influence of plasma treatment on the steel microstructure and resistance. The results are promising and show that this welding process is viable and can even be associated with nitriding to improve the surface characteristics. It was observed that the temperature choice and aging time are fundamental to reach high mechanical resistance levels. Temperature values about 480 oC and time 10,800 seconds proved to be suitable for this treatment. The loss of strength in the welded joints, after the aging treatment, was less than 10%. It was also noticed that when the plasma nitriding treatment is applied, aging occurs simultaneously, therefore it is important to select temperature and treatment time in order to optimized the aging process as well.

• Periodical: Materials Science Forum (Volume 869)
• Pages: 479-483
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.869.479
• Online since: August 2016
• Authors: Sandro Lombardo*, Renan Nascimento Ferreira, Lucas Augusto de Souza Santos, José Wilson de Jesus Silva, Vladimir Henrique Bagio Scheid, Antonio Jorge Abdalla
• Keywords: Aging, Laser Welding, Maraging Steel, Microstructural Characterization, Plasma Nitriding

References

[1] Asm Handbook Online. Asm Desk Editions. Ultrahigh-Strength Steels. Disponível Em <Http: /Products. Asminternational. Org/Hbk/Index. Jsp>. Acesso Em: 14 De Novembro De (2013).

[2] Y. He, K. Yang, W. Qu, F. Kong, G. Su: Materials Letters Vol. 56 (2002), p.763.

[3] A.L.C. Silva, P.R. Mei: Aços e Ligas Especiais. (Editora Blucher 3th. ed. 2010).

[4] J.E. D. Boscov, P. Simpósio: Rocket Motor Cases In 300m Steel – A Pioneer Development Performed In The Brazilian Space Programme,. Loen Norway Esa Sp-229, (1985).

[5] R.M. Anazawa: Caracterização Mecânica E Microestrutural De Um Aço 300m Com Microestrutura Multifásica. Doutorado (Tese). Guaratinguetá, 2007 Faculdade de Engenharia de Guaratinguetá (FEG/UNESP) (SP).

DOI: 10.1590/s1517-70762008000200019

[6] J. Boscov: Foguetes de Sondagem. Brasília: Agência Espacial Brasileira, 1º Curso De Tecnologia Espacial, (1996).

[7] J. Boscov, Veículos Lançadores de Satélites. Brasília: Agência Espacial Brasileira, 1º Curso De Tecnologia Espacial, (1996).

[8] F. Tariq, R.A. Baloch, B. Ahmed, N. Naz: Journal Of Materials Engineering and Performance Vol. 19 (2) (2010), p.264.

[9] R.V. Venkateswara, R.G. Madhusudhan, R.A.V. Sitarama: Materials Science and Technology Vol. 26 (12) (2010), p.1459.

[10] L. Quintino, A. Costa, R. Miranda, D. Yapp, V. Kumar, C.J. Kong: Materials & Design Vol. 28 (4) (2007), p.1231.

[11] E. Kannatey Asibu: Principles of Laser Materials Processing: (Wiley 1th. ed. New Jersey 2009).

[12] S.Y. Sirin, K. Sirin, E. Kaluc: Materials Characterization Vol. 59 (2008), p.351.

[13] [. A.S.M. Cardoso, A.J. Abdalla, M.S.F. Lima, F.M. Bonjorni, M.J.R. Barboza. Baptista, C.A.R.P., Fanton, L. Study Of Laser Welding And Heat Treatments Done In Different High Strength Steels: 4340, 300m, Maraging 300. Technical Paper 2013-36-0510, Sae International, Pg. 1-5, (2013).

DOI: 10.4271/2013-36-0510

[14] L. Fanton, Estudo do Comportamento Mecânico e Microestrutural de um Aço Maraging Após Soldagem a Laser e Tratamentos Térmicos. Mestrado (Dissertação). Guaratinguetá, 1998. Faculdade de Engenharia de Guaratinguetá (FEG/UNESP) (SP).

DOI: 10.26678/abcm.conem2018.con18-1038