Stainless steel knives

[p0689109]

We as a family have the professional range of the Jean Patrique brand of kitchen knives. I have had mine a good few years and have had no problems. My lad has a set and he too has had them a few years. He has not long had a dishwasher installed(about six months) and has found that his set is starting to rust! I realise there are certain grades of stainless but could using a dishwasher cause them to rust? In deed I would have thought that food grade knives should be of the highest grade. Any ideas/comments before I try to tackle the company.

 

[kier]

dishwashers do make some stainless knives have rust spots , I do not put my best cutting knives in the dishwasher

 

[hotrodder]

Very generally hardness/ability to hold an edge and corrosion resistance are kinda at odds with each other... the 3xx series austenitic / 'non magnetic' flavours most people think of when talking stainless are VERY low in carbon, ductile and can't be hardened by thermal treatments. There are various other families of stainless of which the martensitic flavours are the usual suspect for knives http://www.bssa.org.uk/topics.php?article=253
While they 'stain - less' than carbon steels they aren't as corrosion resistant as the austenitics [/gross generalisation]

 

[Mr shiney]

We switched to ceramic. Awesome!

 

[Maker]

We switched to ceramic. Awesome!

Are carbide knives available? Or boron nitride?

 

[TechnicAl]

salt attacks most stainless grades

 

[p0689109]

So how do stainless steel exhausts get on with the winter salt then?

 

[TechnicAl]

So how do stainless steel exhausts get on with the winter salt then?

they dont.........they corrode but they are a different grade that doesnt corrode as much but they will disappear eventually

 

[p0689109]

Thanks TechnicAl. So much for the sales pitch that they will last forever! Stainless is used widely in the boat and yacht fraternity too so what grade do they use and can that be used to make knives that wont rust in the dishwasher?

 

[Maker]

Thanks TechnicAl. So much for the sales pitch that they will last forever! Stainless is used widely in the boat and yacht fraternity too so what grade do they use and can that be used to make knives that wont rust in the dishwasher?

Going by what HR said, I would guess the more corrosion resistant marine grades wouldn't be hard enough to hold an edge if used for a knife.

 

[julianthegypsy]

Thanks TechnicAl. So much for the sales pitch that they will last forever! Stainless is used widely in the boat and yacht fraternity too so what grade do they use and can that be used to make knives that wont rust in the dishwasher?

316L is what's used on boats. I wonder what they use for knives on boats?

 

[hotrodder]

As said 316L is a common 'marine grade' and it can rot quite quickly/badly in salt water despite being more resistant to chlorides than 304L for example http://www.cqj.dk/photo-stainless-steel.htm It might make a good butter knife but it'd be lousy for something that needs to hold an edge

I can't see it being used for cutlery but the internet suggests that there's a 'special' austenitic spring steel that's sometimes used for surgical scalpel blades, X11CrNiMnN19-8-6 http://www.steelnumber.com/en/steel_composition_eu.php?name_id=124 and http://smt.sandvik.com/en/applicati...urgical-tools-and-instruments/scalpel-blades/ where it's called Sandvik 13RM19 and described as having similar corrosion resistance to 301 which is what all the other 3xx are based on/around? The moly and extra nickel in 316 and weld decay/carbide precipitation are explained briefly by TechnicAl in the http://www.mig-welding.co.uk/stainless.htm section. http://www.gowelding.com/met/austenitic.html takes a deeper look

 

[Arash]

Don't forget 3g and CPM series of steels. They cost a lot and are costly to properly heat treat. Most commonly available stainless knives are 440 series stainless steels, they are cheap and easy to heat treat.

As has been mentioned, to make a steel hard in has to contain a percentage of carbon, to make it stainless you have to add chromium, the more of it you add the less carbon can be added hence the reduced wear resistance (blades becoming blunt easily).

This guy explains it better:

 

[graffian]

I can't see it being used for cutlery but the internet suggests that there's a 'special' austenitic spring steel that's sometimes used for surgical scalpel blades

Scalpel blades rust.

 

[ronan]

I've been on a few custom knife makers websites, most seem to use o1 steel for blade making. An odd choice to me as it always seems to rust rather easily.