Thermal Fatigue Properties Of Laser Treated Steels At Semi Solid Processing Temperature
This paper presents the thermal fatigue resistance of laser treated steels. The C40 and AISI H13 steels were machined into a geometry which allowed thermal gradienThermal Fatigue Properties Of Laser Treated Steels At Semi Solid Processing Temperaturets on the inner and outer surface d...
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| Main Authors: | , , , |
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| Format: | Article |
| Published: |
Springer Link
2010
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/1721/ http://umpir.ump.edu.my/1721/1/Thermal_fatigue_properties_of_laser_treated_steels_at_semi-solid_processing_temperature.pdf |
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| Summary: | This paper presents the thermal fatigue resistance of laser treated steels. The C40 and AISI H13 steels were
machined into a geometry which allowed thermal gradienThermal Fatigue Properties Of Laser Treated Steels At Semi Solid Processing Temperaturets on the inner and outer surface during testing. A CO2 laser
system was used with a focused spot size of 0.09 mm on the sample surface. The laser peak power and pulse repetition
frequency (PRF) range were set to 760 and 1515 W, and 2900 to 3500 Hz respectively. The thermal fatigue machine used
consists of Nabertherm model cylindrical high temperature furnace with digital control panel, controlled temperature
quenching system, and pneumatics control sample movement mechanism. The thermal fatigue test involved immersion of
samples into molten aluminium, and quenched in ionised water emulsion at 17
o
C temperature. The quenching system
equipped with thermocouple to control the water temperature. Testing was done at a total of 1,750 number of cycles.
Internal surface cooling was controlled by water inlet and outlet tubes. Samples were cleaned using NaOH solution after
thermal fatigue testing to remove oxides on the surface. The solution temperature and magnetic stirrer speed were set to 100
o
C and 4.5 rpm respectively. Samples were characterised using scanning electron microscope (SEM), energy discharge x-
ray spectroscopy (EDXS) and 2D stylus profilometer. Presence of different phases on the sample surface were analysed
from back-scattered detector micrographs. Heat checks were observed on laser glazed surface at several regions. Carbides
and oxides elements were detected on the sample surface after the thermal fatigue test. The relationship between surface
roughness of laser treated surface and thermal fatigue behaviour was investigated. |
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