ISSN:
1662-9752
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
The hot workability of modified 9Cr-1Mo, as a grade of heat resistant steels, is inferior tothat of low-alloy steel, so the inner surface crack (ISC) easily occurs in seamless boiler tubesproduced by the Mandrel Mill under improper rolling conditions. With the aid of FEM, the metal flowstatus during the rolling process was analyzed in 140mm 8-stand mandrel mill of Bao Steel. Both themetallographic shape and size of the ISC together with the result from the simulation show that theISC of seamless tube forms at the elongation stage of shell. The mechanism of the ISC was discussed.With its initiation in stand No.1 and No.2 due to poor hot workability of modified 9Cr-1Mo steel, theISC develops in subsequent passes. Based upon the mechanism devised was a special roll pass systemwhich substantially upgraded the yield of qualified products
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.61.pdf
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