Which is better: 18/8 or 18/10 stainless steel?

Question

I would like to know about stainless steel , specifically which is stronger and will last longer 18/10 or 18/8. which would make a heavier weight flatware ? I cant find these answers anywhere. thank you so much.

Answer

Hello! Let me start with a few basics, OK? The 18/8 and 18/10 designations are older terms, and refer to the amount of chromium and nickel alloyed with the iron, to comprise the stainless steel. The 18/8 name has been pretty much replaced, in the States at least, by several other designations. 301 stainless steel has 16-18% Cr, and 6-8% Ni 302 stainless steel has 17-19% Cr, and 8-10% Ni 304 stainless steel has 18-20% Cr, and 8-10.5% Ni. That may explain your difficulty in finding information on these alloys. Similarly, 18/10 is usually referred to as 316 stainless steel, with 16-18% Cr, 10-14% Ni, and also 2-3% molybdenum, which greatly increases the resistance to pitting corrosion in seawater. Good stuff, that moly.

Now the mechanical properties these 300 series stainless steels are all the same! In the annealed condition, they are all listed at 75 ksi tensile strength, 30 ksi yield strength. The slight difference in Cr and Ni isn't enough to cause a difference in the strength by themselves. These alloys can be made harder, however, by cold working, i.e. rolling or drawing through a die or extruding through a die or some other such process which will deform the metal, while it is at most a few hundred degrees F. Here, too, the mechanical properties are the same: half-hard stock, for example, has 150 ksi tensile, 110 ksi yield strength, no matter if it is 301, 302, 304, 316, etc.

The difference is in the corrosion resistance (which I assume you're not interested in, since all will be fine for flatware) and in the ductility. A lower alloyed 301 has more ductility when work hardened than the higher alloyed 316. So after you stamp out your quarter hard sheet into forks, you can bend one of the tines more often, or farther, if it is of 301 rather than if it is made of 304 or 316, before it will crack. The weight of the flatware will depend on geometry, since the densities of the stainless steel grades are identical, for practical purposes. Iron, chromium, and nickel all weigh about the same. A splendid source of information on stainless steels is the Nickel Development Institute, at www.nidi.org, which offers a lot of FREE literature they are glad to send. And please don't hesitate to ask here again! (Gosh, I hope I answered your question in all this rambling!) Take care!

Question

Now I'm wondering about 18/0. I've seen a number of flatware sets listed as such. Does the 0 indicate lower quality, less corrosion protection, what not?

Answer

18/0 would mean 18 percent chromium and 0 percent nickel

18/8 indicates 18 percent chromium & 8 percent nickel

18/10 indicates 18 percent chromium & 10 percent nickel.

Because nickel costs about $17 per pound, flatware which contains none would be less expensive than flatware which contains 8 or 10 percent nickel.

While 18/0 is not necessarily unsatisfactory, it is not as corrosion resistant.

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