Laser beam welding tempered 300M ultrahigh mechanical strength steel

Author(s)

de Carvalho, Sheila Medeiros ^[1] ; Fernandes de Lima, Milton Sergio ^[2]

Affiliation

^[1] Inst Aeronaut & Espaco, Div Mecan AME, BR-12228901 Sao Paulo - Brazil

^[2] Inst Estudos Avancados, Div Foton EFO, BR-12228001 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 34, n. 1, p. 18-23, JAN-MAR 2012.
• Web of Science Citations: 3

Abstract

AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding speed and 1200 W laser power. However, both welded materials and heat-affected zones presented high hardness and negligible plastic deformation. In order to produce useful engineering parts, it was suggested a tempering treatment for 2 hours at temperatures of 200 or 400ºC. Tensile mechanical testing has shown that welded and tempered coupons presented both yield and maximum strengths comparable to the unwelded material. On the other hand, a maximum elongation of about 4% was obtained, in comparison with 12% from the bulk sample. (AU)

• FAPESP's process: 07/08265-2 - Characterization of laser treated surfaces by X-ray diffraction
• Grantee: Milton Sergio Fernandes de Lima
• Support Opportunities: Regular Research Grants