Topsecret Generally, it is not advisable to weld 17-4 PH -H1025 grade in as hardened condition. You may have to do preliminary testing to assess if any crack is present and to also check the toughness in hardened condition. Generally the best condition to weld is to solution anneal, weld and do prior age hardening at 550 deg cent for 4 hrs to get hardness in aged condition around 35 HRc (post weld heat treated condition hardness) with prior solution annealing done close to 1040 deg cent. No preheat is necessary. Inter pass temp to be maintained at 120-130 deg cent for 17-4 PH -h 1025 grade during welding. U can refer www.suppliers online.com or Atlas Metal corp for any specific condition you may like to look] Hope this helps C.V.Srinivasan Nishi Engineers Pvt Ltd India Nov 16, 2008 E-mail: nishi@vsnl.com >Is it advisable to weld 17-4PH h1025? I have been told it >may lose some of its hardening properties & weaken the >material, but I am having trouble finding any good >information on this. Information such as, how much would it >be weakened from its normal material properties.? > >Would appreciate any help, thanks, TS.