ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The precipitation behavior of cementite in low carbon steels at various heating rates from0.3 to 100 K/s has been studied using a high-frequency induction heating apparatus. The materialsused in this study were steel plates[removed info]for welded structures: 610 and 780 MPa class steel plates with amixed microstructure of bainite and martensite.[removed info]Cementite was observed using a carbon extractionreplica method and the hardness and toughness were also examined.[removed info] When heated at theconventional slow rate of 0.3 K/s, relatively large cementite particles with an average diameter of72 nm precipitated at the lath boundaries, whereas when heated at a rapid rate over 3.0 K/s,cementite precipitated both within the laths and at the lath boundaries, and the cementite wasrefined down to an average diameter of 54 nm. With such refinement of the cementite, thetoughness was improved. On the other hand, the hardness was irrespective of the heating rate andwas dependent on the tempering parameter. TEM observations of the cementite precipitationbehavior during the rapid heating process revealed that cementite begins to precipitate at the lathboundaries at about 773 K and within the laths at about 873 K. It is concluded that rapid heatingespecially from 773 to 873 K contributes to the cementite refinement and consequently theimprovement in toughness. The effect of alloying elements such as chromium, molybdenum orsilicon on the cementite growth during the rapid heating and tempering treatment is also discussed
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/15/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.539-543.4720.pdf
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