Numerična analiza laserskega pretaljevanja kovinske površine

Peternel, Jaka (author), Govekar, Edvard (mentor)

V pričujočem delu je z numerično analizo obravnavan proces laserskega pretaljevanja kovinske površine na primeru nerjavnega jekla AISI 304. V delu je predstavljen zgrajeni numerični model, ki vključuje absorpcijo laserske svetlobe, prenos toplote, dinamiko talilnega bazena ter pretaljevanje. Pri opisu dinamike tokov talilnega bazena med drugim upoštevamo silo površinske napetosti, Marangonijevo silo in naravno konvekcijo taline. Nadalje so predstavljeni rezultati simulacij za širok nabor procesnih parametrov. Glede na izračunano tokovno polje v talilnem bazenu določimo tipične tokovne vzorce in opišemo rezultirajočo obliko pretaljenega področja in temperaturno polje na površini talilnega bazena ter vpliv porazdelitve intenzitete laserskega žarka na obe polji. Rezultati simulacij so primerjani s predhodno pridobljenimi eksperimentalnimi rezultati geometrije prečnih prerezov pretaljenega območja in temperatur na površini obdelovanca, ki izkazujejo kvalitativno ujemanje. S pomočjo simulacij je nadalje ovrednoten vpliv latentne toplote in dinamike tokov v talilnem bazenu na rezultate simulacij procesa laserskega pretaljevanja kovinske površine.

• Language: Slovenian
• Keywords: numerično modeliranje, proces pretaljevanja površine, multifizikalni modeli, metoda končnih volumnov, nerjavno jeklo, laserski žarki, porazdelitev intenzitete, lasersko navarjanje
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [J. Peternel]
• Year: 2019
• Number of pages: XXII, 71 str.
• PID: 20.500.12556/RUL-109425
• UDC: 621.785.5:621.791.72:519.6(043.2)
• COBISS.SI-ID: 16835099
• Publication date in RUL: 01.09.2019

Secondary language

• Language: English
• Title: Numerical analysis of laser melting of metal surface

Abstract

In this work a numerical analysis of a process of laser melting of metal surface is conducted. We focus on processing of AISI 304 stainless steel. A numerical model of laser light absorption, heat transfer, dynamics of melt pool and melting is presented. Dynamics of melt pool include effects of surface tension force, Marangoni convection and natural convection. Further on results of the analysis are presented which include simulations results in wide range of process parameters. Based on calculated flow field in melt pool typical flow patterns are presented along with resulting melted region and temperature fields on melt pool surface. Effect of laser beam intensity distribution on temperature and velocity fields is discussed. Results of simulations are compared with existing experimentally obtained melted area geometric properties and temperature on surface of a workpiece. Comparison shows qualitative agreement. Based on simulations results an effect of latent heat and melt pool dynamics on the results of the simulations of the process of laser melting of metal surface is analysed.

• Keywords: numerical modeling, surface melting process, multiphysical models, finite volume method, stainless steel AISI 304, laser beams, intensity distribution, laser direct deposition