A1 Refereed original research article in a scientific journal
Effect of optical parameters on fiber laser welding of ultrahigh strength steels and weld mechanical properties at subzero temperatures
Authors: Salminen A, Farrokhi F, Unt A, Poutiainen I
Publisher: AMER INST PHYSICS
Publication year: 2016
Journal: Journal of Laser Applications
Journal name in source: JOURNAL OF LASER APPLICATIONS
Journal acronym: J LASER APPL
Article number: ARTN 022415
Volume: 28
Issue: 2
Number of pages: 7
ISSN: 1042-346X
eISSN: E-ISSN 1938-1387
DOI: https://doi.org/10.2351/1.4943914
Web address : https://lia.scitation.org/doi/10.2351/1.4943914
Abstract
The recently developed direct-quenched ultrahigh strength steels have a combination of high tensile strength and toughness properties at subzero temperatures down to -80 degrees C. The low carbon content of the material is beneficial for weldability. Modern high power lasers provide an excellent opportunity to modify the focal point diameter by changing the feeding fiber diameter, collimation and focal length, and thus modify the beam intensity and heat input in actual welding process. In this study, butt joints of Optim 960 QC direct-quenched ultrahigh strength steel with a thickness of 8 mm were welded with 10 kW fiber laser with various different optical setups in order to evaluate the characteristics of the joints within the range of low to high heat inputs possible for this welding process. The mechanical properties of the joints were studied by subjecting the specimens to a number of destructive tests of mechanical properties. The weld metal hardness and tensile strength was tested. It was found that high quality butt joints with superior tensile strength could be obtained. However, having a high level of all these properties in the joint narrows, the process parameters' window and the heat input needs to be strictly controlled. (C) 2016 Laser Institute of America.
The recently developed direct-quenched ultrahigh strength steels have a combination of high tensile strength and toughness properties at subzero temperatures down to -80 degrees C. The low carbon content of the material is beneficial for weldability. Modern high power lasers provide an excellent opportunity to modify the focal point diameter by changing the feeding fiber diameter, collimation and focal length, and thus modify the beam intensity and heat input in actual welding process. In this study, butt joints of Optim 960 QC direct-quenched ultrahigh strength steel with a thickness of 8 mm were welded with 10 kW fiber laser with various different optical setups in order to evaluate the characteristics of the joints within the range of low to high heat inputs possible for this welding process. The mechanical properties of the joints were studied by subjecting the specimens to a number of destructive tests of mechanical properties. The weld metal hardness and tensile strength was tested. It was found that high quality butt joints with superior tensile strength could be obtained. However, having a high level of all these properties in the joint narrows, the process parameters' window and the heat input needs to be strictly controlled. (C) 2016 Laser Institute of America.
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