The role of beam shape in convection and heat transfer in laser melted pool

Abstract

It is interesting in develop beam pattern used to Kw levels laser wide cladding or alloying. Computer simulation was carried out to determine the role of beam shape in convection and heat transfer in laser melted pool. Four typical beam patterns of A mode 20 × 20mm, B mode 1 × 20mm, C mode 2 × 10mm and D mode 4 × 5mm were used. Temperature profiles and fluid flow fields, thermal cycles and solidfication rates, single pass melted widths and depths, needed laser powers were calculated with M–160 computer for four beam patterns using SIMPLE program. It is shown that linear pattern A has the capability of single pass of melted pool of large widths and shallow depths, low needed input laser power and large cooling rate, it is a good source available to Kw levels laser cladding and alloying. Square pattern B could produce large single pass melted widths and large depths, but needed power is large, it is avariable to 10–20Kw levels laser melting, alloying and cladding. Experiments on melted pool topography, the secondary dendrite arm spacings and laser power are found to be in fair agreement with theoretically calculated values.It is interesting in develop beam pattern used to Kw levels laser wide cladding or alloying. Computer simulation was carried out to determine the role of beam shape in convection and heat transfer in laser melted pool. Four typical beam patterns of A mode 20 × 20mm, B mode 1 × 20mm, C mode 2 × 10mm and D mode 4 × 5mm were used. Temperature profiles and fluid flow fields, thermal cycles and solidfication rates, single pass melted widths and depths, needed laser powers were calculated with M–160 computer for four beam patterns using SIMPLE program. It is shown that linear pattern A has the capability of single pass of melted pool of large widths and shallow depths, low needed input laser power and large cooling rate, it is a good source available to Kw levels laser cladding and alloying. Square pattern B could produce large single pass melted widths and large depths, but needed power is large, it is avariable to 10–20Kw levels laser melting, alloying and cladding. Experiments on melted pool topography, the ...