Pulsative heating of surfaces

In this paper, laser repetitive pulse heating of steel surface is conducted to predict temperature and melt pool geometry in the irradiated region. The enthalpy porosity method is incorporated to account for the phase change in the irradiated surface. The flow field in the melt pool is simulated after considering the Marangoni effect. To examine the influence of the laser pulse intensity distribution on the formation and flow field in the melt pool, the laser pulse intensity parameter (β) is introduced in the analysis. An experiment is conducted to compare the melt pool geometry predicted from the simulation and that obtained from the experiment. The melt pool size is significantly affected by the intensity parameter (i.e., the melt pool is too shallow for high-intensity parameters). The predicted melt pool geometry is in agreement with the experimental results.

show abstract

“…The heat transfer coefficient predicted earlier [21] is used in the present simulations (h t = 10 4 W/m 2 K).…”

Section: Modeling Of Heating and Melting Processmentioning

confidence: 99%

Laser repetitive pulse heating and melt pool formation at the surface

2011

View full text Add to dashboard Cite

show abstract

“…When the material has fully solidified in a cell, the porosity becomes zero and hence the velocities also drop to zero. 19,20 The enthalpy of the material is computed as the sum of the sensible enthalpy, h, and the latent heat, DH:…”

Section: Mathematical Analysis Of Heatingmentioning

confidence: 99%

“…In this case, as the porosity in the mushy zone decreases, the permeability and the velocity also decrease, i.e., when the mushy zone becomes completely solid at the interface of the mushy zone-solid phase, velocity reduces to zero. This behavior can be accounted for by defining the momentum sink as S z ¼ ÀA (v), where A is obtained from Carman-Koseny equation 20 ; in which case, it is shown that A ¼ A mush . 20 Therefore, the momentum sink due to the reduced porosity in the mushy zone takes the following form 19,20 :…”

Section: Mathematical Analysis Of Heatingmentioning

confidence: 99%

See 1 more Smart Citation

Laser melting of alumina‐coated steel

Shuja

Yilbaş

2010

AIChE Journal

View full text Add to dashboard Cite

in Wiley Online Library (wileyonlinelibrary.com).Laser melting of alumina-coated steel surface is considered. Temperature field and phase change in the alumina coating and steel are predicted numerically using the control volume approach. The repetitive laser pulses with 60% duty cycle are incorporated in the analysis. The porosity-enthalpy method is adapted to account for the phase change. It is found that steel at alumina coating interface undergoes a melting before alumina after the end of heating of the 2nd pulse. The melt pool size of alumina is smaller than that corresponding to steel. The resolidification of the melt pool takes place in the alumina coating, whereas the melt pool remains in steel beneath the alumina coating during the cooling cycle. V

show abstract

“…When a laser beam of intensity I0 is irradiated on the surface of the material and it results in the excitation of free electrons in metals, vibrations in insulators and both in semiconductors [14][15][16]] The excitation energy is directly converted into heat (time duration in the range 10-13 s for metals, 10-12 to 10-6s for nonmetals) [17,18]. This is followed by various heat transfer processes such as conduction into the materials, convection, and radiation from the surface.…”

Section: Effect Of Lasers In Surface Processing Of Materialsmentioning

confidence: 99%

Laser Based Surface Processing of Engineering Materials - State of Art

I.A¹,

N.J²,

S³

et al. 2008

Int. Jour. Des. Manf. Tech.

View full text Add to dashboard Cite

An overview is given on the state of art of the laser based surface processing of engineering materials. In major engineering application surface of the material plays a major role. since the surface has the direct contact with the environment as well as the load. The different parameters such as hardness, toughness, wear resistance etc on the surface has to be enhanced based on the application, hence there is a need to go for surface processing. Conventional surface processing has its own limitations toward recently developed materials and other functional aspects. These aspects can be overcome by laser based surface processing. In this paper an attempt has been made to investigate the principal and effect of laser interaction on materials such as heating, surface melting, vaporization, plasma formation , ablation etc .The different types of laser based surface processing of engineering materials based on their properties, Processing parameters and functional aspects which is considered for different application has been discussed.

show abstract

Pulsative heating of surfaces

Cited by 30 publications

References 2 publications

Laser repetitive pulse heating and melt pool formation at the surface

Laser repetitive pulse heating and melt pool formation at the surface

Laser melting of alumina‐coated steel

Laser Based Surface Processing of Engineering Materials - State of Art

Contact Info

Product

Resources

About