抄録
Investigations were carried out to clarify the influence of Mn and Ti on age-hardening behaviors of 17Cr-7Ni PH stainless steel. The results obtained are as follows:
(1) The age-hardening behavior of 17Cr-7Ni steel containing 0.9%Ti is comparable with that of the commercial 17-7 PH stainless steel containing 1.4%Al.
(2) Steel in which part of Ni is substituted with Mn and Ti is not added shows age-hardening as well.
(3) Steel containing Mn and Ti shows remarkable age-hardening due to the complex effect of the Ni-Mn precipitate and the Ni-Ti precipitate.
(4) These stainless steels are age-hardened if the matrix of the steels is martensite or delta-ferrite, while they are not hardened if it is austenite. The amount of age-hardening in the steels is roughly estimated from a special structural diagram showing the phases in the steel quenched from 1050°C and the increment of hardness due to age-hardening at 500°C for 1 hr.
