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Material characterization studies on the laser beam formed AISI 1008 mild steel

  • Authors: Kumpaty, Subha , Brossard, Bradley , Kamara, Sheku , Akinlabi, Stephen A. , Akinlabi, Esther Titilayo , Raju, Govinda , Panda, Nirmal , Balasubramanian, K.
  • Date: 2014
  • Subjects: Mechanical forming , Laser beam forming , Metal deformation
  • Type: Article
  • Identifier: uj:4743 , ISSN 978-93-81505-62-5 , http://hdl.handle.net/10210/11729
  • Description: Laser Beam Forming is a new non-contact method without the use of a die, to achieve deformation in metals, which traditionally involved the application of mechanical forces to change the shape and form of the material permanently. Laser forming causes deformation by introducing thermal stresses from an external heat source as opposed to the simple application of forces in mechanical forming. In this study, samples were formed mechanically by using a dynamic press brake machine, whereby, a punch and die apply the force. A 4.4 kW Nd:YAG laser system was used to form a second set of samples made from cold rolled AISI 1008 mild steel using laser forming. In this collaborative work involving researchers from the USA, South Africa and India, the mechanical and metallurgical properties of the unformed, mechanically formed and laser formed samples were experimentally investigated. The objective is to compare these properties amongst the different samples in order to analyze the impact of the varying methodologies especially the laser energy effects on the samples. The conclusions from these tests have provided valuable information on the applicability of laser forming to attain the appropriate surface modifications yielding the desired mechanical and metallurgical properties of the metal.
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Laser beam forming of 3 mm steel plate and the evolving properties

  • Authors: Akinlabi, Stephen , Shukla, Mukul , Akinlabi, Esther Titilayo , Tshilidzi, Marwala
  • Date: 2011
  • Subjects: Laser beam forming , Deformation , Elongated grains
  • Type: Article
  • Identifier: uj:5325 , ISSN 1307-6884 , http://hdl.handle.net/10210/8239
  • Description: This paper reports the evolving properties of a 3 mm low carbon steel plate after Laser Beam Forming process (LBF) To achieve this objective, the chemical analyse material and the formed components were carried out and compared; thereafter both were characterized through microhardness profiling, microstructural evaluation and tensile testing. The chemical analyses showed an increase in the elemental concentration of the formed component when compared to the as received material; this can be attributed to the enhancement property of the LBF process. The Ultimate Tensile Strength (UTS) and the Vickers microhardness of the formed component shows an increase when compared to the as received material, this was attributed to strain hardening and grain refinement brought about by the LBF process. The microstructure of the as received steel consists of equiaxed ferrit and pearlite while that of the formed component exhibits elongated grains.
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The influence of scanning speed and number of scans on the properties of laser formed steel

Forming behaviour of steel sheets after mechanical and laser beam forming

  • Authors: Akinlabi, Esther Titilayo , Shukla, M. , Akinlabi, S. A. , Kanyanga, S. B. , Chizyuka, C. M.
  • Date: 2014
  • Subjects: Laser beam forming , Mechanical forming , Microhardness , Microstructure , Tensile testing , Steel plates - Mechanical properties
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/379024 , uj:4998 , http://hdl.handle.net/10210/13136
  • Description: This paper reports the influencing factors and the characteristic behaviour of steel plates during both the mechanical forming and laser beam forming processes. Samples of the steel sheets were mechanically bent to 120 mm curvatures using a 20 ton capacity eccentric mechanical press at room temperature and also with the laser beam using a 4.4 kW Nd: YAG laser system at a scan speed of 1.9 m/min, beam diameter of 12 mm, laser power of 1.7 kW at 25% beam overlap using argon for cooling the irradiated surfaces. The chemical composition of both the as-received material and the formed samples were analysed by emission spectroscopy to quantify the changes in the elemental composition. The result shows a percentage increase in the carbon after the mechanical and laser forming processes when compared to the parent material. This can be attributed to the enhancement resulting from the forming processes. The formed samples were further characterized through microstructure, microhardness and tensile tests. The microstructural characterisation of the samples revealed that the grains of the mechanically formed and laser formed components are elongated, it was also observed that there is an increase in the pearlite grains of the laser formed components resulting from the thermal heating during the laser process. The microhardness profiles of the formed components showed that there is a significant percentage increase in the Vickers microhardness values of the laser formed samples when compared to the mechanically formed samples and with respect to the parent material. The laser beam forming process can be considered a more appropriate forming process in terms of the resulting material properties in this regard.
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Laser forming of titanium and its alloys – an overview

Experimental investigation of laser beam forming of titanium and statistical analysis of the effects of parameters on curvature

  • Authors: Akinlabi, Stephen A. , Akinlabi, Esther Titilayo
  • Date: 2013
  • Subjects: Laser beam forming , Titanium alloys
  • Type: Article
  • Identifier: uj:4746 , ISSN 2078-0966 , http://hdl.handle.net/10210/11732
  • Description: Laser beam forming, a non-contact manufacturing process has become a viable manufacturing process for shaping metallic components. The capability of laser beam forming and bending demands more experimental studies to identify an optimized parameter setting and the likely parameters influencing the formed curvature. This paper investigates experimental laser beam forming of Ti6Al4V titanium alloy using a 4.4 kW Nd: YAG laser and studied the effects of the process parameters on the formed curvature. It was established that an increase in both the laser beam power and the number of scan tracks reduces the radius of curvature in the formed sheets having a more dome shape. The scan speed on the other hand, achieved the same good curvature at a slower or reduced scan speed to allow enough laser – material interaction. Furthermore, both the ANOVA and the regression analysis confirmed the repeatability of the experimental data. A simple regression model was developed based on the known active parameters to determine approximate curvatures instead of running a series of experiments.
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