ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Microstructural changes and hardness variations in SKD11 steel have been investigatedduring the processes of carbide dispersion (CD) carburizing, austenitization, subzero treatment andtempering. The carbon content of the surface region increased up to 3.0% after CD carburizing, andthe surface phases consisted of two predominant types of M7C3 carbides (large primary eutecticM7C3 carbide and secondary M7C3 carbide), retained austenite and martensite. After austenitization,the carbon content of the surface region decreased to 2.4%. At the same time, surface hardness wasreduced from 900Hv for the CD carburizing condition to 830Hv after austenitization. On the otherhand, the hardness at the interior region of the austenitized steel displayed a 100Hv higher valuethan that of the CD carburizing steel. In spite of removal of the retained austenite, subzero treatment(at -100[removed info]) of the austenitized steel resulted in a decrease in hardness, probably due to the softeningof the martensite matrix. However, tempering (at 200[removed info] for 4 hours) of the subzero treated steelraised its hardness up about 70Hv compared to steel tempered without the subzero condition, due toprecipitation of fine nano size carbides below 50nm
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.118.115.pdf
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