Abstract
This study develops a thermodynamic model
to investigate the quasi-steady thermal process of a wide thin steel
workpiece irradiated with a moving Gaussian laser beam. Equations are
established for temperature distribution, transformation boundaries,
homogenisation time of austenite and cooling rate. The equations are
numerically solved with an error of less than 10−8.
The temperature distributions for various thicknesses are compared with
that for infinite thickness at different laser traverse speed. The lag
of the peak temperature relative to the centre of laser beam is found to
be limited. The conditions to produce full and partial martensite are
investigated. The model is verified by comparing the calculated Ac1 and Ac3
depths and temperature cycles with the experimental results. For AISI
4340 steel, correction coefficients are applied to the model to produce
an empirical equation for temperature cycles above 488.4°C.
| Original language | English |
|---|---|
| Pages (from-to) | 131-153 |
| Journal | International Journal of Computational Materials Science and Surface Engineering |
| Volume | 5 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2013 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- modelling
- hardening
- Gaussian laser beam
- thermal cycle
- temperature distribution
- cooling rate
- hardened depth.