Thick section laser and hybrid laser welding of austenitic stainless steels

Veli Kujanpää

    Research output: Contribution to journalArticleScientificpeer-review

    14 Citations (Scopus)

    Abstract

    Austenitic stainless steels are generally known to have very good laser weldability, when ordinary grades of sheets are concerned. But it is not necessarily the case, if special grades of fully austenitic structures with e.g. high molybdenum, or thick-section are used. It is also known that hot cracking susceptibility is strictly controlled by composition and welding parameters. If solidification is primary ferritic, hot cracking resistance is dramatically increased. It is also well known that laser welding needs a careful control of weld edge preparation and air gap between the edges. The dependence on edge quality can be decreased by using filler metal, either cold wire, hot wire or hybrid laser-arc welding. An additional role is high molybdenum contents where micro segregation can cause low local contents in weld which can decrease the corrosion properties, if filler metal is not used. Another feature in laser welding is its incomplete mixing, especially in thick section applications. It causes inhomogeneity, which can make uneven microstructure, as well as uneven mechanical and corrosion properties In this presentation the features of laser welding of thick section austenitic stainless steels are highlighted. Thick section (up to 60 mm) can be made by multi-pass laser or laser hybrid welding. In addition to using filler metal, it requires careful joint figure planning, laser head planning, weld parameter planning, weld filler metal selection, non-destructive and destructive testing and metallography to guarantee high-quality welds in practice. In addition some tests with micro segregation is presented. Also some examples of incomplete mixing is presented.
    Original languageEnglish
    Pages (from-to)630-636
    JournalPhysics Procedia
    Volume56
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed
    Event8th International Conference on Laser Assisted Net Shape Engineering, LANE 2014 - Fürth, Germany
    Duration: 8 Sep 201411 Sep 2014

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    Keywords

    • Laser welding
    • Hybrid laser welding
    • multi-pass welding
    • austenitic stainless steel
    • solidification
    • thick-section
    • metallurgy
    • hot cracking

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