Patent ID: 7481970
Filing Date: 2009-01-27
Classification: C22C

Abstract:
1. A heat resistant alloy for use as material of engine valve consisting essentially of, in mass percent, C of 0.01 to 0.15%, Si of 0.01 to 0.8%, Mn of 0.01 to 0.8%, Cr of 14 to 17%, Mo of more than 3.0% but equal to or less than 5.0%, Al of 1.6 to 2.5%, Ti of 1.5 to 3.0%, Nb or Nb+Ta of 0.5 to 2.0%, Ni of 50 to 60%, B of 0.001 to 0.015%, at least one of Mg of 0.001 to 0.015% and Ca of 0.001 to 0.015%, and the balance being Fe, wherein value A defined by 0.293[Ni]−0.513[Cr]−1.814[Mo] is 2.0 to 5.8, value B defined by [Al]/([Al]+[Ti]+[Nb]+[Ta]) is 0.45 to 0.65, and value C defined by [Al]+[Ti]+[Nb]+[Ta] is 6.2 to 7.6, wherein brackets mean atomic % of each element in the heat resistant alloy, and wherein a ratio of maximum Cr content to minimum Cr content is equal to or less than 1.2 when a line analysis of Cr segregation is performed on a cross section of the heat resistant alloy by an EPMA.