TY - JOUR
T1 - Characterisation of quasi-stationary temperature fields in laser welding by infrared thermography
T2 - Charakterisierung von quasi-stationären Temperaturfeldern beim Laserstrahlschweißen durch Infrarotthermographie
AU - Francis, J. A.
AU - Gach, S.
AU - Olscho, S.
AU - Reisgen, U.
AU - Haeusler, A.
AU - Gillner, A.
AU - Poprawe, R.
PY - 2018/1/10
Y1 - 2018/1/10
N2 - In this work, high-speed thermography is shown to effectively capture quasi-stationary temperature fields during the laser welding of steel plates. This capability is demonstrated for two cases, with one involving the addition of a ferritic-bainitic filler wire, and the other involving the addition of a low-transformation-temperature (LTT) filler wire. The same welding parameters are used in each case, but the temperature fields differ, with the spacing between isotherms being greater in the case where the low-transformation-temperature filler material is added. This observation is consistent with the differences in the extent of the heat-affected zone in each sample, and the shape of the weld pool ripples on the weld bead surfaces. The characterization of temperature fields in this way can greatly assist in the development of novel methods for reducing residual stresses, such as the application of low-transformation-temperature filler materials through partial-metallurgical injection (PMI). This technique reduces or eliminates tensile residual stresses by controlling the temperature fields so that phase transformations take place at the optimum times, and success can only be guaranteed through precise knowledge of the temperature fields in the vicinity of the welding heat source in real time.
AB - In this work, high-speed thermography is shown to effectively capture quasi-stationary temperature fields during the laser welding of steel plates. This capability is demonstrated for two cases, with one involving the addition of a ferritic-bainitic filler wire, and the other involving the addition of a low-transformation-temperature (LTT) filler wire. The same welding parameters are used in each case, but the temperature fields differ, with the spacing between isotherms being greater in the case where the low-transformation-temperature filler material is added. This observation is consistent with the differences in the extent of the heat-affected zone in each sample, and the shape of the weld pool ripples on the weld bead surfaces. The characterization of temperature fields in this way can greatly assist in the development of novel methods for reducing residual stresses, such as the application of low-transformation-temperature filler materials through partial-metallurgical injection (PMI). This technique reduces or eliminates tensile residual stresses by controlling the temperature fields so that phase transformations take place at the optimum times, and success can only be guaranteed through precise knowledge of the temperature fields in the vicinity of the welding heat source in real time.
KW - Cooling rate
KW - heat-affected zone (HAZ)
KW - phase transformation
KW - residual stress
KW - temperature measurement
KW - welding thermal cycle
UR - http://www.scopus.com/inward/record.url?scp=85040325777&partnerID=8YFLogxK
U2 - 10.1002/mawe.201700160
DO - 10.1002/mawe.201700160
M3 - Article
AN - SCOPUS:85040325777
SN - 0933-5137
VL - 48
SP - 1283
EP - 1289
JO - Materialwissenschaft und Werkstofftechnik
JF - Materialwissenschaft und Werkstofftechnik
IS - 12
ER -