Precipitation hardening stainless steels
AssigneeDaido Tokushuko Kabushiki Kaisha
InventorsTomonao Tateyama, Tetsuya Shimizu, Michio Okabe
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Abstract
A precipitation hardening stainless steel, which is excellent in cold workability at a solution treated state and good in proof stress after overaging treatment, consists essentially of C.ltoreq.0.010, Ni 0.010.about.0.025% (provided C+N.ltoreq.0.025%), Si.ltoreq.1.0%, Mn.ltoreq.1.2%, P.ltoreq.0.040%, S.ltoreq.0.030%, Cu: 3.0.about.5.0%, Ni: 3.0.about.4.65%, Cr: 13.0.about.16.5%, Mo.ltoreq.1.0%, Nb: (-11.43 (C+N)+0.6).about.0.5% and the balance Fe on condition that 452 (C+N)+11.1 (Ni+Mn).ltoreq.73.1.
Claims8
A precipitation hardening stainless steel for cold working consisting essentially by weight percentage of not more than 0.010% of C and 0.010 to 0.025% of N with the proviso that the total sum of C and N does not exceed 0.025%, not more than 1.0% of Si, not more than 1.2% of Mn, not more than 0.040% of P, not more than 0.030% of S, 3.0 to 5.0% of Cu, 3.0 to 4.65% of Ni, 13.0 to 16.5% of Cr, not more than 1.0% of Mo, (-11.43 (percent C+percent N)+0.6) to 0.5% of Nb and the balance being substantially Fe with further proviso that C, N, Ni and Mn are correlated such that
- 452 (percent C+percent N)+11.1 (percent Ni+percent Mn)
- is at most equal to 73.1, wherein volume percentage of an austenite phase observed after aging treatment is not more than 20%.
A precipitation hardening stainless steel for cold working consisting essentially by weight percentage of not more than 0.010% of C and 0.010 to 0.025% of N with the proviso that the total sum of C and N does not exceed 0.025%, not more than 1.0% of Si, not more than 1.2% of Mn, not more than 0.040% of P, not more than 0.030% of S, 3.0 to 5.0% of Cu, 3.0 to 4.65% of Ni, 13.0 to 16.5% of Cr, not more than 1.0% of Mo, (-11.43 (percent C+percent N)+0.6) to 0.5% of Nb, at least one element selected from 0.0005 to 0.0100% of Ca, 0.0005 to 0.0100% of B and 0.0005 to 0.0100% of rare earth metals and the balance being substantially Fe with further proviso that C, N, Ni and Mn are correlated such that
- 452 (percent C+percent N)+11.1 (percent Ni+percent Mn)
- is at most equal to 73.1, wherein volume percentage of an austenite phase observed after aging treatment is not more than 20%.
Dependencies are inferred from the claim text.