Why is my stainless silverware rusting?

Question

I recently purchased some cheap silverware that stated it was "stainless". Obviously it is not because they are getting little rust spots on them. Any way I did the magnet test and they are not stainless steel as the magnet stuck to them.

I decided to do the same test on a silverware set purchased seperately that is not rusting and the magnet stuck to them as well! I also tried the magnet on a more pricey set and the same thing. All of this silverware states that it is stainless.

Why are some rusting and others are not, and why do they say they are stainless?

What might this silverware really be made out of and is it toxic or contain allergens?

Answer 1

There are different grades and types of stainless, depending upon the chemicals added to the iron during processing.

Stainless steels are a very broad group of metals. The name was adopted as a generic term for steel alloys with a minimum of 10.5% chromium. The chromium gives the steel its 'stainless' properties - essentially corrosion resistance. On the surface of the metal, a very thin chromium-rich oxide layer is formed which is inert - i.e. it prevents the steel from rusting. The advantage of stainless steels over plated steels is that, if scratched or damaged, the steel will 'self-repair' as a new oxide layer is formed. In plated steels, scratches in the plate will often lead to corrosion of the steel underneath.

In general, the higher the proportion of chromium, the stronger the corrosion resistance of the steel. In addition to chromium, other metals are added to give the steel particular properties such as strength and malleability. Specifically nickel is used to strengthen the oxide layer.

As for whether they are magnetic, the answer is that it depends. There are several families of stainless steels with different physical properties. A basic stainless steel has a 'ferritic' structure and is magnetic. These are formed from the addition of chromium and can be hardened through the addition of carbon (making them 'martensitic') and are often used in cutlery. However, the most common stainless steels are 'austenitic' - these have a higher chromium content and nickel is also added. It is the nickel which modifies the physical structure of the steel and makes it non-magnetic.

So the answer is yes, the magnetic properties of stainless steel are very dependent on the elements added into the alloy, and specifically the addition of nickel can change the structure from magnetic to non-magnetic.

The following company website has a useful high-level definition of the broad stainless steel categories. http://www.parkrow.org/stainless_steel.h...

Answer 2

Stainless Steel is manufactured in different grades for use in various environments. 300 series would be used for every day tableware. 400 series can be hardened depending on

the  carbon content. And may be used for the finest cutlery. Although 400 series is stainless steel it is more prone to rusting than 300 series and extra care is required to keep it clean. Stainless steel is approximately  75% iron and can and will rust if not keep clean. 303 stainless is the orginial stainless steel and is was designated 18-8 stainless steel, in the old designation system, for the percentages of nickel and chromium in the steel. Which imparts the stainless ability to the steel. There isn't any practical way to know the chemical composition of the steel in your Tableware. All Stainless is magnetic and is not a test for determining a stainless steel.

I'm sorry to say there is a lot of sub-standard steels that ends up in the market place. And an uniformed buyer of steel can purchase these products and have them placed into production. Which in turn ends up with the consumer. And the consumer ends up with a low quality products. Sometime a bargain turns out not to be a bargain. It looks like that's what happened to you!

Answer 3

There are different types of "stainless" steel. The ones most resistant to rust are the ones with the highest "Nickel" content. They are also more expensive. Type 316 is virtual resistant to rusting except when left laying in battery acid. Type 304, on the other hand, will rust if left wet for too long.

Answer 4

it is probably a flatwear, even stainless will rust if put in a dishwasher, chemical in dishwasher detergent will eat the nickel from the silverware, then it will rust, stop putting in the washer and wash them by hand. most metalware is not dishwasher safe, the ware is not toxic, will not hurt you