Evaluation of solidification cracking susceptibility during laser welding in advanced high strength automotive steels

G. Agarwal*, A. Kumar, I. M. Richardson, M. J.M. Hermans

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    41 Citations (Scopus)
    248 Downloads (Pure)

    Abstract

    Solidification cracking susceptibility during laser welding was studied experimentally and numerically in advanced high strength steel sheets, namely transformation-induced plasticity (TRIP) and dual phase (DP) steel. Using the same heat input, laser bead-on-plate welding was carried out on single sided clamped specimens at various starting distances from the free edge. It was observed that TRIP steel with high phosphorus is susceptible to cracking while in DP steel with low phosphorus, solidification cracking was not observed. The metallurgical factors affecting the solidification cracking were studied and it was found that solidification morphology, phosphorus segregation at the prior austenite grain boundaries, inclusions, interface growth rate and interdendritic liquid feeding have a prominent effect on the strength of the mushy zone. These results are discussed pertaining to the cracking mechanism. For the same welding parameters, a difference in the weld pool shape was observed in both the steels, which is attributed to the high temperature thermophysical properties. Weld pool shape affects the strain distribution in the mushy region and thus the cracking behaviour. The cracking phenomenon is further described using hot ductility curves.

    Original languageEnglish
    Article number108104
    Number of pages12
    JournalMaterials and Design
    Volume183
    DOIs
    Publication statusPublished - 2019

    Keywords

    • Advanced high strength steels
    • Automotive
    • Laser welding
    • Solidification cracking
    • Weld pool shape

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