What is stainless steel?
Stainless Steel is all around us, it is used for benches, tapware, ovens, rangehoods… Stainless steel is the generic name for a number of different steels used primarily because of their corrosion resistance. All stainless steels share a minimum percentage of 10.5% chromium. It is this element that reacts with the oxygen in the air to form a complex chrome-oxide surface layer that is invisible but strong enough to prevent further oxygen from “staining” (rusting) the surface.
The film itself is extremely thin, about 130 Angstroms and one Angstrom is one millionth of a centimeter. This layer is described as passive (does not react or influence other materials), tenacious (clings to the layer of steel and is not transferred elsewhere) and self-renewing (if damaged, more chromium from the steel will be exposed to the air and form more chromium oxide).
This means that over a period of years a stainless steel knife can literally be worn away by daily use and will still remain stainless. Higher levels of chromium and the addition of other alloying elements such as nickel and molybdenum enhance this surface layer and improve the corrosion resistance of the stainless material. Chromium is always the deciding factor, although other elements, particularly nickel and molybdenum, are added to improve corrosion resistance.
Furthermore, stainless steel is fully recyclable.
What is the difference between 304 and 316 stainless steel?
304 contains 18% chromium and 8% nickel. 316 contains 16% chromium, 10% nickel and 2% molybdenum. The “moly” is added to help resist corrosion to chlorides (like sea water and de-icing salts.
Can stainless steel be “welded”?
YES. Stainless steel is easily welded, but the welding procedure is different than that used with carbon steel. The “filler” rod or electrode must be stainless steel.
What temperatures can stainless steel withstand?
Stainless steel has excellent properties at both extremes of the temperature scale. Some stainless steel can be used down to liquid nitrogen temperatures and some up to about 980 Degrees Celsius.
What is the recycle content of stainless steel?
Stainless steel can be recycled 100%. That is all stainless steel can be re-melted to make new stainless steel. The typical amount of recycled stainless steel “scrap” that is used to make new stainless steel is between 65 & 80%.
Can stainless steel rust? Why? (I thought stainless did not rust!)
Stainless does not “rust” as you think of regular steel rusting with a red oxide on the surface that flakes off. Corrosion is generally caused by contaminants settling on the surface of the stainless steel.