Rust on Stainless Steel Utensils

Verisure

Verisure

Senior Member
Lately, my stainless steel knives and forks have been coming out of the dishwasher with rust spots. I’ve been using the same machine for more than a year now and I use the correct salt and rinse liquid in the machine but since a few weeks ago …. ! There must be an explanation and a remedy, but what can it be?
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There are many types of stainless steel depending on how much nickel and chromium are added to ordinary steel.
Different grades of stainless steel are made for different purposes, but more and more, to keep prices down, there is a lot of 'so called' stainless steel on the market. It has very little chromium or nickel in it, so it can show rust spots. A lot of this is coming from China.
 
I have some pretty good quality stainless steel flatware that has developed a few unsightly nicks that turn black.

Similar to timoc’s post I was told that it was due to nicks and abrasions in the chromium top coat that develop with use over time.

I was advised to live with it because the more you fight it the worse it will become.
 

Stainless steel is a steel alloy that contains a minimum chromium content of 10.5%. The chromium reacts with the oxygen in the air and forms a protective layer that makes stainless steel highly resistant to corrosion and rust. ... But, over time and if not maintained correctly, rust can and will develop on stainless steel.
So, what can cause stainless steel to rust? Exposure to corrosive process fluids and cleaners, high humidity or high salinity environments such as sea water can remove the native protective layer (chromium oxide) and can cause stainless steel corrosion. Removing surface rust from surfaces improves the appearance, but it's importance goes beyond the decorative.
Timoc makes a good point, if your cutlery is an import chances are the chromium content is too low to resist that which can attack it.

Phosphoric acid will dissolve iron oxide without attacking the other components of the steel (chromium and chromium oxide, nickel, and iron.) Phosphoric acid is readily available from a number of commercial suppliers and it can be used with no dilution because of its non-aggressive nature. Clean up after acid treatment is done by thoroughly rinsing parts in deionised water to remove any remaining acid on the surface. If deionised water is not available, rinse with distilled water.

Unfortunately, this technique is not 100% effective on all the forms of iron oxide and other surface preparation treatments could be necessary. But when all is said and done you have to ask how much did you pay for the cutlery, is it worth all the effort to restore it and would it not be a better option to simply replace your cutlery with something that's of better quality?
 
Stainless steel type 304, is what we used exclusively for the food industry, it contains 8% nickel and 18% chromium, along with small amounts of carbon, nitrogen and manganese and is one of the most expensive stainless steels, but as I mentioned in an earlier post, lots of items arriving from far eastern countries masquerading as food quality stainless steel, are in fact poor grade metal.
 
timoc said:
Stainless steel type 304, is what we used exclusively for the food industry, it contains 8% nickel and 18% chromium, along with small amounts of carbon, nitrogen and manganese and is one of the most expensive stainless steels, but as I mentioned in an earlier post, lots of items arriving from far eastern countries masquerading as food quality stainless steel, are in fact poor grade metal.
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I'm pleased someone has an answer for this, thanks Tim ... because lately I've been wondering why some of my stainless steel knives ( in particular knives).. have been getting these rust spots like the OP... and now I know, and I've been throwing those items that are affected into the bin ( and not even as bad as the OPs') How irritating for the manufacturers not to let the consumer aware there are levels of stainless steel and not all are rustproof.. I would have bought a much higher quality cutlery set instead of stainless steel from Ikea if I'd known...
 
Aunt Bea said:
I have some pretty good quality stainless steel flatware that has developed a few unsightly nicks that turn black.

Similar to timoc’s post I was told that it was due to nicks and abrasions in the chromium top coat that develop with use over time.

I was advised to live with it because the more you fight it the worse it will become.
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how do you mean by 'the more you fight it, the worse it will be '' Aunt Bea ?... In what way could you fight it ?.. Do you mean using abrasive cleaners on it or what do you mean , I'm a bit confused? :unsure:
 
hollydolly said:
I'm pleased someone has an answer for this, thanks Tim ...
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Timoc's observation of cheap imports struck a chord. Someone I know, paid a lot of money for stainless steel wheels on his car. The wheels started to corrode around three months after the warranty had expired. It turned out that they were Chinese imports and he could have bought wheels of a far superior quality for just a hundred pounds or so more. It is certainly the case of buyer beware these days.
 
horseless carriage said:
Timoc's observation of cheap imports struck a chord. Someone I know, paid a lot of money for stainless steel wheels on his car. The wheels started to corrode around three months after the warranty had expired. It turned out that they were Chinese imports and he could have bought wheels of a far superior quality for just a hundred pounds or so more. It is certainly the case of buyer beware these days.
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that makes me absolutely furious, one of the things that is guaranteed to get me angry is being ripped off!!!
 
@everyone
So, the simple answer is that the "stainless" part of the steel is starting to get worn out and the cheaper the quality the sooner it happens. I suppose that I could get to work with some abrasive cleaner and do them by hand, but I'm sure that'll only wear them out even quicker. Time to buy some new forks and knives!
 
horseless carriage said:
..... Someone I know, paid a lot of money for stainless steel wheels on his car. The wheels started to corrode around three months after the warranty had expired ......
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It is not a mere theory that some products are designed to go bust soon after the warranty/guarantee runs out. I saw a documentary once about just that using the German light bulb Osram as an example. It was sold in two choices, one more expensive than the other. It turns out that they were the very same bulb but the cheaper model was fitted with an extra device that would cause it to burn out sooner than the more expensive one.
 
@timoc, @horseless carriage and others are right. Lots of different grades and types of stainless steel ( https://www.unifiedalloys.com/blog/stainless-grades-families/ ), none of which are completely "stainless". Some are better than others, which depends a bit on use. My rule of thumb is the more expensive the higher quality, but that takes a bit of research to verify.
Verisure said:
So, the simple answer is that the "stainless" part of the steel is starting to get worn out and the cheaper the quality the sooner it happens. I suppose that I could get to work with some abrasive cleaner and do them by hand, but I'm sure that'll only wear them out even quicker. Time to buy some new forks and knives!
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Yep, pretty much.
 
I've still got some 'Richardsons of Sheffield' cutlery, I can't remember how long I've had them, old fashioned maybe, but still the best money can buy in my humble opinion. :)
 
hollydolly said:
how do you mean by 'the more you fight it, the worse it will be '' Aunt Bea ?... In what way could you fight it ?.. Do you mean using abrasive cleaners on it or what do you mean , I'm a bit confused? :unsure:
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Some people say baking soda and vinegar or WD40 will help to remove it. The problem is that it will eventually remove more of the topcoat in those areas and make the problem worse.

I really don’t know but I always tend to take the path of least resistance.😊
 
Aunt Bea said:
Some people say baking soda and vinegar or WD40 will help to remove it. The problem is that it will eventually remove more of the topcoat in those areas and make the problem worse.

I really don’t know but I always tend to take the path of least resistance.😊
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In this case, the path of least resistance is also the most sensible path ... purchase new ones.
 
Our SS silverware is over 20 years old, and we noticed some "spots" on it a couple of years ago. We started adding some "Finish Jet Dry" to the dishwasher, and that seemed to take care of the problem. When the bottle of "finish" ran out, we switched over the the Walmart "Equate" brand, which has the same formula, for half the price...and no more troubles with "spots".
 
Don M. said:
Our SS silverware is over 20 years old, and we noticed some "spots" on it a couple of years ago. We started adding some "Finish Jet Dry" to the dishwasher, and that seemed to take care of the problem. When the bottle of "finish" ran out, we switched over the the Walmart "Equate" brand, which has the same formula, for half the price...and no more troubles with "spots".
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We use "Fixa" rinse liquid but I'm pretty sure we used "Finish" before so maybe the problem started when I switched brands? Anyway, Missour-a is a bit too far for me to travel to find a Walmart to buy "Equate". :)
 
Verisure said:
We use "Fixa" rinse liquid but I'm pretty sure we used "Finish" before so maybe the problem started when I switched brands? Anyway, Missour-a is a bit too far for me to travel to find a Walmart to buy "Equate". :)
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I don't have a dishwasher here and it happens to my cutlery using the top brand dish washing liquid .. but equally it happens in Spain where I do have a dishwasher..but in Spain I just presumed it was the lack of quality of the cutlery...
 
hollydolly said:
I don't have a dishwasher here and it happens to my cutlery using the top brand dish washing liquid .. but equally it happens in Spain where I do have a dishwasher..but in Spain I just presumed it was the lack of quality of the cutlery...
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..... or "hard" water? I am going to switch brands of rinsing liquid today and see if it makes a difference.
 
Our SS cutlery is 50 years old and I’ve noticed some spots in the past couple of years. We have hard water and use Finish.

It really shocked me when I realized the age.
 
Verisure said:
..... or "hard" water? I am going to switch brands of rinsing liquid today and see if it makes a difference.
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We have some of the hardest water in the UK in this area...... 355 calcium carbonate levels ppm or mg/l:

We're rated as having ‘hard to very hard water’. That is because our county contains more limestone and chalk in the ground than most other regions
 


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