What makes stainless steel stainless?
Stainless steel must contain at least 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. 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.

What is the 18/10 stainless steel?
The first number is the amount of chromium that is contained in the stainless, i.e., 18 is 18% chromium. The second number is the amount of nickel, i.e., 10 stands for 10% nickel. 18/10 is 18% chromium and 10% nickel. The higher the numbers the more corrosion resistant the material.18/10 contain nickel and are part of the grade family "300 series" stainless. 18/0 means that there is 18% chromium but zero nickel. When there is no nickel the stainless grade family is the "400 series". 400 series are not as corrosion resistant as the 300 series and are magnetic, where the 300 series are non-magnetic.

Can stainless steel rust? Why?
Stainless does not "rust" as you think of regular steel rusting with a red oxide on the surface that flakes off. If you see red rust it is probably due to some iron particles that have contaminated the surface of the stainless steel and it is these iron particles that are rusting.
Expecially be aware to contact with the metals such a aluminium,copper and iron from the stainless steel.

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.

Is stainless steel magnetic?
There are several "types" of stainless steel. The 400 series (which just contains chromium and no nickel as ferritic charater) are magnetic.The 300 series (which contains nickel) is NOT magnetic unless might be effected of cold drawing and physical machinery or sand blasting they reveal magnetic charaters.

What is "passivation"?
When the amount of chromium exceeds 10,5%, a complex chrome oxide forms instantaneously that prevents the further diffusion of oxygen into the surface and results in the "passive" nature of stainless steel and its resistance to oxidation (or corrosion). A chemical "dip" into 10% nitric acid plus 2% hydrofluoric acid bath will enhance the development of this "passive" oxide.

Can Stainless steel be "hardened"?
YES. The 300 series stainless steel can be "hardened" BUT only by "work hardening." That is by cold working the material, either by cold rolling down to lighter and lighter gauges, or by "drawing" through a die or other size altering operation. "Annealing" stainless steel will REMOVE the work hardening effect. YES and NO. The 400 series have two different stainless steel structures. One is called "ferritic" (409, 430, 434. 439) which cannot be hardened by heat treatment. The other is called "martensitic" (403, 410, 416, 420, & 440 A,B,C) which CAN be hardened by heat treatment.

What does the "L" designation mean?
The use of the letter L after the grade number, i.e., 304L, means that the carbon content is restricted to a MAXIMUM of 0.03% (normal levels are 0.08% max. and in some grades can be as high as 0.15% max.). This lower level of carbon is usually used where "welding" will be performed. The lower level of carbon helps to prevent the chromium from being depleted (by forming chrome carbides at the weld site) and therefore allow it to remain over 10,5% so it can form the "passive" oxide layer that gives stainless its corrosion resistance in a flexible physical structure.

What is the recycle content of stainless steel?
Stainless steel can be recycled 100%. That is all stainless steel can be re-melted to made a new stainless steel. The typical amount of recycled stainless steel "scrap" that is used to make new stainless steel is between 65 & 80%.

The stainless steel is scratched. How can I remove the scratches?
Scratches are difficult to remove. Most kitchen appliances, sinks, and counters have a polished finish with short directional polishing lines. Restoring a polished finish to its original appearance requires a professional such as a company that specializes in fabricating or polishing stainless steel. If the refrigerator or dishwasher door panel is replaceable, purchasing a new panel is normally more cost effective than professional refinishing.The counter or appliance using a non-metallic abrasive pad such as a Scotch Brite® pad.These will not eliminate deep scratches.

What is the "annealed" condition?
Stainless steel is usually sold in the "annealed" condition. It just means that the material is in the "soft" or annealed condition. The 300 series of stainless steels can not be hardened by heat treatment (like carbon steels) but can be hardened by cold working. This cold work can be eliminated by a heating treatment (annealing) that will restore the original soft condition.

Can stainless steel be used at very low and very high temperatures?
Yes.Stainless steel has excellent properties due to "grade"at both extremes of the temperature scale. Stainless steel can be used down to liquid nitrogen temperatures(-196°C) and up to about 1000° C.

What are AISI Specifications for stainless steel?
The AISI (American Iron and Steel Institute) was the originator of the 300 and 400 series numbering system (i.e., Type 304 stainless steel). They also published a Stainless Steel products manual that listed these designations and the chemical analysis as well as most mechanical and physical properties of each individual grade. They are NOT specifications as such, just definitions of the individual grades. Most specifications that are used with stainless steel are from the ASTM (American Society for Testing Material).

Can stainless steel be machined?
Yes. However the standard grades of stainless steel are usually "gummy" and will not produce a clean chip when machined or turned. To solve this problem, many companies produce "free-machining" grades of stainless where they add a "chip-breaker" to the matrix. Grade 303 is the free-machining equivalent to grade 304.

What is the standard finish mean for stainless steel like 2B?
Cold rolled, heat treated, pickled, pinch passed. The most common cold rolled mill finish. Dull grey slightly reflective finish.

Do you need to "preheat" stainless steel before welding?
NO. Austenitic stainless steel (the 300 series) do not need to be preheated before welding.

What is sandblasting?
Sandblasting is a general term used to describe the act of propelling very fine bits of material at high-velocity to clean or etch a surface. Sand used to be the most commonly used material, but other materials are now used in its place. Any small, relatively uniform particles will work, such as steel grit, Due to the dangers of inhaling dust during the process, sandblasting is carefully controlled, using an alternate air supply, protective wear, and proper ventilation.