I think people tend to use them interchangeably, based on what is most available.
If it is a new, and critical, application I personally would have greater faith in the validity of the Swedish-generated corrosion data for S32750.
H900 has rather low toughness & is susceptible to SCC. Might suggest you consider H950 after re-solution annealing. Tensile strength is not everything.
Phosphoric acid does remove rust, slowly.
A 5% solution of H2PO4 that is widely available is trademarked Coca-Cola. I'd use the regular, not the diet. Vaguely recall sugar helps modify things. Antique dealers have used a Coke soak to (slowly) clean up old iron stuff
If this is too ludicrous...
Most knowledgable corrosion engineer I know is Sheldon Dean, Dean Corrosion Technology, Allentown, Pennsylvania tel 610-439-1054
www.deancorrtech.com The Rolled Alloys & Outokumpu guys are good, Dean has industrial experience with a broad range of alloys.
6%Mo grades such as N08926, a.k.a. Cronifer 1925hMo, are normally welded with 625 (ERNiCrMo-3) so that, in spite of Mo segregation, the weld bead will still meet corrosion resistance of the base metal.
Other 6Mo stainlesses, which may be more available in the size and product form you need...
Stainless alloys which can resist corrosion in undersea applications include the superaustenitic grades AL-6XN (UNS N08367) made in the US, and 254 SMO (UNS S31254) from Outokumpu in Avesta, Sweden.
The superduplex stainless steels, such as SAF 2507 (UNS S32750, 1.4410) and ZERON 100 (UNS...
Wonder if it is possible to cool 1600kg fast enough, from whatever is that specified anneal temperature, to end up with any ductility? Have you checked the hardness of this casting?
Agree w EdStainless in all points.
Do think it would be cool to know exactly which superduplex alloy is involved.
Whatever is "Grade 5" it does not refer to a specific alloy chemistry.
If you are saying that Nitronic 50 fails by stress corrosion cracking (SCC), then I would use AL-6XN/254 SMO, whichever is available.
If in fact Nitronic 50 WORKS and is available, I'd seriously consider using it.
Yeah, the 6%Mo grades are better but AVAILABILITY of the parts you want + good...
Simplest, and available/weldable, choice for seawater is one of the 6% molybdenum stainless grades. AL-6XN is stocked by Rolled Alloys in many sizes and forms, as is 254 SMO by Outokumpu. Better crevice corrosion resistance than 316.
Duplex 2205 is better than 316, widely available; more...
Just curious - that cast HSLA isn't a grade that would embrittle, is it, at the nominal 850F/454C temperature used for hot dip galvanizing?
In any event, the weldment should be stress relieved before hot dip to avoid cracking from molten zinc.
304 stainless, 18Cr 9Ni, is not suited for long term service at 1750F. It will get thin and go away, disappear, from oxidation.
You might try 310 (nominal 25Cr 20Ni, actually available stuff is 310S UNS S31008)
It will still gall.
In Ancient Times General Electric's jet engine guys in...
Ammonia may crack the Cu alloy but sulfer from sewage corrodes them. Copper alloy heat exchanger tubing not so good in rivers for this reason. The Susquehanna comes to mind.
I worked for a supplier of specialty heat and corrosion resistant alloys. Metallurgist, wrote all the technical data sheets.
Corrosion data, CPT, tensile, yield are all very interesting and surely must be considered.
But there is one more very important material property.
And that is...
316/316L is not suitable for long time seawater service.
625 is great, could be a little more than needed.
The 6% molybdenum stainless steels, such as AL-6XN (UNS N08367) have given good long-term seawater service and are less expensive than is 625 (UNS N06625) They are available from...
430 is a ferritic stainless with nominal 16.5% chromium. It is magnetic, so if that matters to you one can hang magnetic refrigerator notes on it.
304 is an austenitic stainless, nominal 18% chromium 8% nickel. It is non-magnetic, mostly, and forms better. Is more costly,because of that 8%...
My guess is your supplier was sold 304 bar, which THEIR supplier claimed to be 316. That 2% molybdenum in 316 is what gives 316 better molten zinc resistance than 304.
Carbon content is unlikely to be the issue. All, or 99% of all, 316 is really 316L (S31603) with enough process modifications...
For best corrosion resistance you do need to remove the heat colors, also any embedded iron. The iron comes from contact with tools, clamps, steel or cast iron tables, shear blades, et cetera.
Stainless steel passivates - forms that thin chromium oxide film - just by exposure to air. All you...
If they butted 1/4" 2205 plate together and welded without beveling the joint, then one fine day the joint will break apart. Any manner of cyclic loading, mechanical or thermal, can cause that unwelded area to act like a crack and grow out through the weld bead to the surface.
Unlike carbon...