Post-weld tempered microstructure and mechanical properties of hybrid laser-arc welded cast martensitic stainless steel CA6NM

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DOIResolve DOI: http://doi.org/10.1007/s11663-015-0578-5
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
ISSN1073-5615
Pages112; # of pages: 12
SubjectCarbon; Electric arc welding; Electric welding; Fiber lasers; Heat affected zone; Hybrid materials; Laser materials processing; Low carbon steel; Martensitic stainless steel; Mechanical properties; Microstructure; Steel fibers; Tensile strength; Turbine components; Turbines; Welding; Welds; Arc welding process; Charpy impact energy; Fully-penetrated; Hybrid laser arc welding; Tempered lath martensites; Tempered microstructure; Ultimate tensile strength; Stainless steel
AbstractManufacturing of hydroelectric turbine components involves the assembly of thick-walled stainless steels using conventional multi-pass arc welding processes. By contrast, hybrid laser-arc welding may be an attractive process for assembly of such materials to realize deeper penetration depths, higher production rates, narrower fusion, and heat-affected zones, and lower distortion. In the present work, single-pass hybrid laser-arc welding of 10-mm thick CA6NM, a low carbon martensitic stainless steel, was carried out in the butt joint configuration using a continuous wave fiber laser at its maximum power of 5.2 kW over welding speeds ranging from 0.75 to 1.2 m/minute. The microstructures across the weldment were characterized after post-weld tempering at 873 K (600 °C) for 1 hour. From microscopic examinations, the fusion zone was observed to mainly consist of tempered lath martensite and some residual delta-ferrite. The mechanical properties were evaluated in the post-weld tempered condition and correlated to the microstructures and defects. The ultimate tensile strength and Charpy impact energy values of the fully penetrated welds in the tempered condition were acceptable according to ASTM, ASME, and industrial specifications, which bodes well for the introduction of hybrid laser-arc welding technology for the manufacturing of next generation hydroelectric turbine components.
Publication date
PublisherSpringer International Publishing
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); Aerospace
Peer reviewedYes
NPARC number21277449
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Record identifier9b472c78-10d4-4125-b3a9-090281dd9365
Record created2016-03-09
Record modified2016-05-09
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