Time-resolved temperature measurement during laser marking of stainless steel. (October 2018)

• Record Type: Journal Article
• Authors: Kučera, M.; Martan, J.; Franc, A.
• Is Part Of: International journal of heat and mass transfer. Volume 125(2018)
• Page Start: 1061
• Page End: 1068
• Publication Date: 2018-10
• Subjects: Time-resolved temperature measurement -- Laser marking -- Nanosecond -- Corrosion resistance -- Stainless steel; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2018.04.137
• Languages: English
• ISSNs: 0017-9310

Abstract

Graphical abstract: Highlights: Time resolved temperature measurement first applied to laser marking. New measurement system developed. Correlation found between temperature, microstructure and corrosion resistance. Longer pulses at high frequency do not induce surface melting (max. 1200 °C). Shorter pulses induce surface melting (1600–1900 °C) and low corrosion resistance. Abstract: A new measurement system was developed for time-resolved surface temperature measurement in nanosecond time scale. A study of surface temperatures reached by different parameters of laser marking and their correlation with resulting microstructure, phase composition and corrosion tests performed on marked samples is presented. The marking was done using a nanosecond pulsed fibre laser with variable pulse duration (from 9 to 200 ns), repetition frequency and pulse energy. Different phase composition and corrosion resistance were observed for visually similar marking results obtained by different laser parameters. This correlates well with maximum temperatures reached in the laser spot, which varied from less than 1100 °C for longer pulses to more than 1800 °C for shorter pulses. Melting of the surface with up to 4 µm thickness was observed for marking processes inducing high temperatures. The maximum temperatures in the pulse depend not only on pulse duration but also on previous pulses due to the heat accumulation effect. A temperature difference of up to 500 K was observed due to heat accumulation. From the results it can be concluded that combinations of longer pulse duration and higher repetition rate are the most suitable parameters for preserving corrosion resistance of stainless steel after laser marking.