DLRose S.S. 431 is a martensiticgrade S.S with Nickel 1.5 to 2.5%. Its corrsosion properties are best and nearly comparable with S.S. 304 when heat treated at 450-620 deg centrigrade after an anneal and tempering treatment, In tempered conditions - 450 to 620 deg centirgrade, its impact properties are enhanced by 50% than in annealed condition. Its strength is maintained between 850 - 1000 MPA. Y.S is also enhanced by 50%. This material is used for bolting, pumping shaft , propeller applications - generally. It has poor weldability. This has to borne in mind while using this for some applications. Heat treatment cost is negligible compared to enhanced corrosion resittance properties you derive or get with this material. Smooth surface and heat treatment will give you better corrosion properties for S.S 431. As a casting try to improve the surfae finish to get enhanced corrosion resistance with this material. Annealing and Tempering is needed from higher yiels strength, higher impact strength and corrosion resitance. Cutting short of heat treatment (tempering at 600 deg centigrade is nto advisable in my opinion) Hope this answers your question. C.V.Srinivasan Nishi Engineers Pvt Ltd Chennai India March 29 E-mail: nishi@vsnl.com >We typically use cast 431 SS in a heat treated condition >(anneal at 1024C for one hour, air cool, Temper at 690C for >3 hours, air cool). > >A goal is to reduce cost by eliminating this heat treatment. > However, we are being told that the corrosion properties >will suffer if not heat treated. Can anyone provide any >comments on this? Is it likely that corrosion properties >will suffer if 431 SS is not heat treated in this fashion?