Does non-magnetic or magnetic stainless steel leach more?

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SUMMARY

The discussion centers on the leaching properties of non-magnetic versus magnetic stainless steel cookware. It is established that austenitic stainless steels, which are non-magnetic and contain more than 10% nickel, can leach nickel depending on the pH of the food being cooked. In contrast, ferritic and martensitic stainless steels, which are magnetic and contain lower nickel levels (less than 7%), do not leach as much nickel. The corrosion of both types is influenced by the acidity of the food, with high acid content leading to pitting in both categories.

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  • Understanding of stainless steel types: austenitic, ferritic, and martensitic
  • Knowledge of nickel's role in stainless steel composition
  • Familiarity with pH levels and their effects on metal leaching
  • Awareness of surface passivity and corrosion mechanisms in metals
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  • Research the leaching properties of austenitic stainless steel in acidic environments
  • Explore the effects of pH on metal corrosion and leaching
  • Investigate the manufacturing processes of different stainless steel grades
  • Learn about the health implications of nickel leaching from cookware
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Cooks, kitchenware manufacturers, materials scientists, and anyone interested in the safety and performance of stainless steel cookware.

fangrz
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May I know whether non-magnetic or magnetic stainless steel cookware leach more? I have looked at the different reasons why some stainless steel is magnetic or not, but it is confusing me whether one leaches more than the other.
 
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No matter what particular grade of stainless steel is used, the stainless characteristic comes from surface passivity due to the chromium content. Stainless steel is usually only stable in the presence of oxygen. The corrosion of stainless steel cookware is dependent on what is being cooked. Food with a high acid content will tend to pit the surface of both magnetic or non-magnetic stainless steel.

https://en.wikipedia.org/wiki/Pitting_resistance_equivalent_number

The material will be selected by the manufacturer based on the available forming processes and the finish required. Some stainless steels can be more easily rolled into thin sheet, some can be polished.
 
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fangrz said:
May I know whether non-magnetic or magnetic stainless steel cookware leach more? I have looked at the different reasons why some stainless steel is magnetic or not, but it is confusing me whether one leaches more than the other.
Stainless steels come three major types: austenitic, ferritic and martensitic, and then duplex combinations, e.g., austenitic-martensitic or martensitic-ferritic.

Austenitic stainless steels are nonmagnetic, while ferritic and martensitic stainless steels are magnetic.

Austenitic steels have more nickel (usually > 10% wt Ni). Ni is an austenite stabilizer. Ni tends to leach out of stainless steel depending on pH of the solution in contact with the stainless steel.

Ferritic and martensitic steels tend to have low nickel < ~7%, or even < 5%. Chromium is a ferrite stabilizer.

http://steel.keytometals.com/articles/art50.htm
 
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