scholarly journals Effect of Heat Treatment and Transformation on Bending Angle in Laser Forming of Titanium Foils

2007 ◽  
Vol 344 ◽  
pp. 243-250
Author(s):  
Masaaki Otsu ◽  
Yasuhiro Ito ◽  
Akira Ishii ◽  
Hideshi Miura ◽  
Kazuki Takashima
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Laser Power ◽  
Pure Titanium ◽  
Foil Thickness ◽  
Laser Forming ◽  
Bending Angle ◽  
History Of ◽  
Yvo4 Laser ◽  
Titanium Foils

Pure titanium foils were bent by laser forming and the effect of c-d transformation and history of heat treatment of specimen on bending angle was investigated. The thickness of specimens was changed from 40 to 100om, the length of them was 20mm and the width of them was 10mm. The specimens were annealed at 600-1100oC for 30 minutes in argon atmosphere. A 20W YVO4 laser was employed and laser power was changed from 2 to 16W. From the experimental results, when laser power was increased, bending angle also increased and it was dramatically changed at the laser powers occurring c-d transformation and melting. Bending angle increased as grain size increased and it jumped up when grain size exceeded the foil thickness and then became constant. Bending angle decreased by annealing after forming and degree of decrease was greater when the annealing temperature before forming was lower.

Bending Deformation of Pure Titanium Plate in CO2 Laser Forming

2007 ◽  
Vol 329 ◽  
pp. 625-630 ◽  
Author(s):  
Koichi Okuda ◽  
Y. Sugie ◽  
Masayuki Nunobiki
Keyword(s):  
Co2 Laser ◽  
Laser Power ◽  
Pure Titanium ◽  
Laser Spot ◽  
Laser Forming ◽  
Titanium Plate ◽  
Bending Angle ◽  
Spot Diameter ◽  
Bending Deformation ◽  
Laser Spot Diameter

This study deals with behaviour of bending deformation in CO2 laser forming process of titanium. CO2 laser forming technique was applied for a pure titanium plate with thickness of 1 mm to aim the development of new bending process. The experiments of laser forming were carried out with a CO2 laser machine. The bending angle and the temperature of workpiece were examined under the condition of various laser power, feed speed and laser spot diameter. Based on the experimental results, it was found that the bending deformation behaved greatly depending on the laser power and the laser spot diameter. The bending angle increased with an increase in the laser power. The bending direction tended to change from the laser irradiation side to its opposite side when the large laser spot diameter was applied.

scholarly journals In Situ Digital Image Correlation Observations of Laser Forming

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 17 ◽  
Author(s):  
Herman Fidder ◽  
Joris P. J. Admiraal ◽  
Václav Ocelík ◽  
Jeff Th. M. De Hosson
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Heat Affected Zone ◽  
Laser Power ◽  
Pure Titanium ◽  
Processing Parameters ◽  
Image Correlation ◽  
Laser Forming ◽  
Bending Angle

In this study experimental and modelling methods are used to examine the microstructural and bending responses of laser-formed commercially pure titanium grade 2. The in situ bending angle response is measured for different processing parameters utilizing 3D digital image correlation. The microstructural changes are observed using electron backscatter diffraction. Finite element modelling is used to analyse the heat transfer and temperature field inside the material. It has been proven that the laser bending process is not only controlled by processing parameters such as laser power and laser beam scanning speed, but also by surface absorption. Grain size appears to have no influence on the final bending angle, however, sandblasted samples showed a considerably higher final bending angle. Experimental and simulation results suggest that the laser power has a larger influence on the final bending angle than that of the laser transverse speed. The microstructure of the laser heat-affected zone consists of small refined grains at the top layer followed by large elongated grains. Deformation mechanisms such as slip and twinning were observed in the heat-affected zone, where their distribution depends on particular processing parameters.

scholarly journals Effect of Heat Treatment and Transformation on Bending Angle in Laser Forming of Titanium Foils

2007 ◽  
pp. 243-250
Author(s):  
Masaaki Otsu ◽  
Yasuhiro Ito ◽  
Akira Ishii ◽  
Hideshi Miura ◽  
Kazuki Takashima
Keyword(s):  
Heat Treatment ◽  
Laser Forming ◽  
Bending Angle ◽  
Titanium Foils

Investigating the Effect of Process Parameters and Scan Strategy During Laser Forming of Thin Open Celled Aluminium Foam

2018 ◽  
Author(s):  
Mohammad Shahid Raza ◽  
Talari Srinu ◽  
Susmita Datta ◽  
Partha Saha
Keyword(s):  
Process Parameters ◽  
Laser Processing ◽  
Laser Power ◽  
Metal Foams ◽  
Parent Material ◽  
Aluminium Foam ◽  
Laser Forming ◽  
Micro Computed Tomography ◽  
Bending Angle ◽  
Scan Speed

The present study provides detailed investigation on the effect of various laser processing parameters and scan strategy during laser forming of thin open-celled aluminium foam. Previous research on laser bending showed that metal foams can be formed by laser processing, but it is very difficult to form the metal foams mechanically owing to their brittle nature. The 2D Laser forming operation was carried out using 2 kW fiber laser with laser power and scanning speed as input process parameters while bending angle was calculated as an output parameter. The effect of laser power, scan speed, number of scans and scan distance from the edge on bending angle of the foam were analyzed and presented. It was observed that the laser processing showed a decrease in bending angle with an increase in scan speed except for 1750 W power, where after 12500 mm/min the bending angle did not follow the trend. The bending angle decreased with increase in number of scans probably due to strain hardening effect. The effect of scan distance from the edge was different for lower process parameter combinations {600 W, 2500 mm/min} and {1000 W, 4000 mm/min}, where the bending angle was maximum for a distance of 20 mm from edge in 1400 W, 7500 mm/min scan speed. For 1750W, 11000 mm/min bending angle was maximum for 80 mm distance from edge. The SEM analysis showed that the major concern associated with laser forming of open-celled Aluminium foam is foam melting. EDS and XRD analysis showed that formation of different oxides and compounds of Aluminium increases with increases in laser power and scan speed. Micro-Computed Tomography (micro-CT) analysis confirmed the absence of crack during laser forming and the pore density variation during laser forming was clearly visible between laser processed zone and the parent material zone.

Microstructural Modification of Laser-Bent Open-Cell Aluminum Foams

2012 ◽  
Vol 504-506 ◽  
pp. 1213-1218 ◽  
Author(s):  
Loredana Santo ◽  
Denise Bellisario ◽  
Ludovica Rovatti ◽  
Fabrizio Quadrini
Keyword(s):  
Laser Heating ◽  
Laser Power ◽  
Laser Forming ◽  
Processing Conditions ◽  
Aluminum Foams ◽  
Laser Bending ◽  
Bending Angle ◽  
Open Cell ◽  
Scan Rate ◽  
Alloy Microstructure

Laser forming tests have been performed on open-cell aluminum alloy foams with different pore size. Laser power was fixed at 150 W, a total of 150 laser scans led to a bending angle up to 60°, depending on the laser scan rate. At the end of the laser bending, the foams were left to cool and samples were extracted for analysis by means of an optic microscope. The alloy microstructure was investigated in different points of the samples and correlated with the processing conditions. Image analysis was also carried out to extract the percentage of melted area due to laser heating.

An experimental investigation of parameters effect on laser forming of Al6061-T6 sheets

2015 ◽  
Vol 231 (5) ◽  
pp. 433-442 ◽  
Author(s):  
Amir H Roohi ◽  
H Moslemi Naeini ◽  
M Hoseinpour Gollo
Keyword(s):  
Laser Power ◽  
Sheet Thickness ◽  
Laser Forming ◽  
Direct Relation ◽  
Beam Irradiation ◽  
Forming Process ◽  
Bending Angle ◽  
Thermal Forming ◽  
Laser Beam Irradiation ◽  
Experimental Runs

Laser forming, which is categorized as a thermal forming process, is used in forming and bending of metallic and non-metallic sheets. Laser beam irradiation causes a localized temperature increase and a localized mechanical strength decrease. In this article, the effects of four process parameters, comprising laser power, scan velocity, the number of scan passes, and sheet thickness, on laser forming of Al6061-T6 sheets are studied. A design of experiment, including response surface methodology, is carried out to limit the experimental runs and costs and to identify the parameter effects on the bending angle of the sheet. Experiment results show that bending angle increases due to the decrease of scan velocity and sheet thickness. In addition, laser power and number of scan passes have a direct relation with a final sheet forming.

Influence of Strain Gradient on Springback of Thin Pure Titanium Foils in Microbending Assisted by Resistance Heating

2016 ◽  
Vol 716 ◽  
pp. 215-224
Author(s):  
Qiu Zheng ◽  
Tetsuhide Shimizu ◽  
Ming Yang
Keyword(s):  
Grain Size ◽  
Strain Gradient ◽  
Elevated Temperatures ◽  
Pure Titanium ◽  
Bending Moment ◽  
Resistance Heating ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
Titanium Foils ◽  
Good Agreement

Strain gradient is known as an important factor that influences springback of bent components in microscale. Compared with thicker foils, thinner foils usually indicate more strain gradient due to non-uniform material deformation. A resistance heating (RH) method is an effective approach to obtain homogenous material flow by heating foils within only several minutes. To predict springback of foils bent at elevated temperatures, an investigation of the influence of strain gradient on springback is indispensable. To achieve this, microbending tests assisted by RH were conducted at different temperatures ranging from 298 to 723 K in the present study. 0.05 mm-thick pure Ti foils with varying grain sizes of 2.7, 14.7, and 24.5 μm were used. As results, normalized bending moment decreased with increasing temperature and with increasing grain size. The less strain gradient of the foils with larger grain size and at elevated temperatures was confirmed to be the reason according to a theoretical analysis of springback using the constitutive model considering statically stored dislocations (SSDs) and geometrically necessary dislocations (GNDs). The predicted normalized bending moment by theoretical calculation showed good agreement with experimental results at the temperature of 573 K or higher but not at the temperature lower than 573 K. It was found that the springback of the foils was influenced by the strain gradient at low temperatures. Furthermore, the size effects caused by strain gradient reduced as the bending temperature increases.

Effect of Heat Treatment on Bending Angle in Laser Forming

2004 ◽  
Vol 2004.12 (0) ◽  
pp. 445-446
Author(s):  
Masaaki OTSU ◽  
Yasuhiro ITO ◽  
Hideshi MIURA ◽  
Akira ISHII
Keyword(s):  
Heat Treatment ◽  
Laser Forming ◽  
Bending Angle

Bending of Pure Titanium Sheet to Curved Surface Shape by Laser Forming Technique

2010 ◽  
Vol 126-128 ◽  
pp. 388-393 ◽  
Author(s):  
Masayuki Nunobiki ◽  
Koichi Okuda ◽  
Kousuke Hourai ◽  
Hiroo Shizuka
Keyword(s):  
Pure Titanium ◽  
Surface Shape ◽  
Curved Surface ◽  
Experimental Result ◽  
Laser Forming ◽  
Convex Curve ◽  
Titanium Sheet ◽  
Bending Angle ◽  
Scanning Velocity ◽  
Straight Line

This paper deals with laser forming procedure to bend pure titanium sheets along arbitrary curved shape. In preliminary experiments, single straight-line bending was carried out and the relationship between bending angle and laser irradiation conditions was investigated. It was clarified that the bending angle was able to control with scanning velocity and the number of scanning passes. With use of obtained experimental formula for the bending angle, we tried to bend the Ti sheet along given parabola shape with a multi straight-line bending. The experimental result was corresponding to the target shape well. This paper proposed a laser forming procedure for curved shapes which include both convex curve and concave curves. It was confirmed that it was able to curve a titanium sheet along arbitrary curved surface with proposed method.

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