Patent ID: 6514359
Filing Date: 2003-02-04
Classification: C21D,C22C

Abstract:
A heat resistant steel which comprises, by mass %, C: 0.01-0.25%, Cr: 0.5-8%, V: 0.05-0.5%, Si: not more than 0.7%, Mn: not more than 1%, Mo: not more than 2.5%, W: not more than 5%, Nb: not more than 0.2%, N: not more than 0.1%, Ti: not more than 0.1%, Ta: not more than 0.2%, Cu: not more than 0.5%, Ni: not more than 0.5%, Co: not more than 0.5%, B: not more than 0.1%, Al: not more than 0.05%, Ca: not more than 0.01%, Mg: not more than 0.01%, Nd: not more than 0.01%, with Fe and impurities accounting for the balance, the chemical composition of which satisfies the relations (1) and (2) given below and in which, among precipitates inside grains, precipitates having an average diameter of not more than 30 nm are present at a density of not less than 1/&mgr;m3:Câˆ’0.06Ã—(Mo+0.5 W)&gE;0.01â€ƒâ€ƒ(1), Mn+0.69Ã—log(Mo+0.5 W+0.01)&lE;0.60â€ƒâ€ƒ(2), wherein, in the above formulas (1) and (2), the symbols for elements represent the contents, on the % by mass basis, of the elements in the steel.