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Characterization of titanium laser welds
Chmelíčková, H. ; Hiklová, H. ; Václavek, L. ; Tomáštík, J. ; Čtvrtlík, Radim
Butt welding of commercially pure titanium Grade 1 and Ti6Al4V alloy sheets using a pulsed Nd:YAG laser KLS 246 - 102 LASAG were carried out to determine optimal values of pulse energy and pulse length to create completely penetrated weld. Surface peak power density of about 3.105 W.cm−2 was found as an optimal value. Weld dimensions, both face width and penetration depth, are found to be proportional to increasing energy and decreasing pulse length. Gentle sagging and root penetration were revealed by means of contact surface profilometry. The nanohardness tests on transverse cross-sections detected approximately 50% higher hardness in the fusion zone than in the base material.\n
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Laser welding of stainless steel tubes
Chmelíčková, Hana ; Lapšanská, Hana ; Hiklová, Helena ; Havelková, Martina
Laser axial welding is a modern method of production of tubes with seam which are mainly used in automotive and food-processing industry. Welding experiments with AISI 304L stainless steel sheet were conducted using continual high power CO2 laser with maximal power 5 kW. The aim of these experiments was to evaluate the effect of processing parameters on weld dimensions and surface properties. Subjected parameters were laser power, shielding gas flow and its composition. Modern contact profilometry was applied to display weld surfaces. Metallographic specimens of weld cross sections were prepared to measure the weldarea. Temperature field distribution was modeled using finite element software SYSWELD.
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Optimalizace parametrů laserového přetavování povrchu
Chmelíčková, Hana ; Kaňa, J. ; Hiklová, Helena ; Lapšanská, Hana ; Havelková, Martina
Laser beam with power density 102 W.mm-2 causes metal surface melting without material vaporization. Temperature gradient between melted spot centre and solid state boundary is formed, surface structure is changed. Cooling rate affects melted zone microstructure. In result, surface quality, porosity, homogenization, mechanical and chemical resistivity are improved. Laser melting parameters optimization of steel samples was made by means of pulsed solid state laser with average power 100 W. Energy, pulse length, feed speed and laser beam diameter were subsequently changed. Melted traces on steel surface were analyzed to discover microstructure and dimensions of affected zones. Result dependence on process parameters was evaluated and optimal parameters were chosen.
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Mapování povrchu pevných těles kontaktním profilometrem
Hiklová, Helena
Taylor Hobson instrument Form Talysurf Series 2 is introduced into this paper. This device is mechanical contact inductive profilometer for measuring roughness, waviness and form of solid surfaces. Owing to special electric circuitry it is able to work with extraordinary resolution and high accuracy. To get possession of more complete picture of the surface the instrument can create 3D surface topography by software controlled measuring row of parallel profiles. Measurements are analyzed via PC using the TalyMap software manufactured by Taylor Hobson Precision.
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