Induction pots

Have you ever bought a set of stainless steel dishes and it rusted in your dishwasher? As shown below, no problem.

Induction heating pots are usually made of food grade stainless steel type 18/10, ie. that steel has 18% chromium and 10% nickel. This corresponds to steel type AISI 304 (EN 1.4301). It is a typical austenitic stainless steel, which is non-magnetic and at the same time very well suited for its corrosion resistance to contact with food at high temperatures.

However, if you have induction heating, you will not heat anything in such a pot precisely because the steel is non-magnetic. So for this to work, steel must be added to the bottom of the pot, which is both magnetic and corrosion resistant. Both of these properties are not easily achievable for steel in this combination. Therefore, it is necessary to choose ferritic stainless steel, which has just these two properties, such as steel AISI 430 (EN 1.4016), known in the food industry as steel 16/0. That is, steel with 16% chromium, no nickel.

From the end customer’s point of view, it doesn’t matter. Nobody in the kitchen cares much about these details. Everything starts to be solved only when we pull the pot out of the dishwasher as shown.

Fig. 1 – Corroded pot bottom                                            Fig. 2 – Principle of induction heating

Where they went wrong? You start with yourself first. You’re researching what you did wrong. Was it a mistake that we cooked in that dish? Probably not, that’s why you bought them. So you contact the seller, the one to the manufacturer, and within 30 days you will find out that the blame is definitely on your side. You used the wrong dishwasher, the wrong tablets or you just exposed the pots to aggressive environments.

So again. Where they went wrong? Who will help me? Is it possible to prove that the pots are made of the material that is notified, ie 18/10 and 16/0?

In this case, the help is simple. There are devices for determining the chemical composition of steel, which can determine the content of these essential elements in a few seconds. Although they are not able to determine carbon, this does not play a significant role in this case, almost none can be there anyway.

In the case of the bottom of the pot, according to the seller, it should be a 16/0 material, ie steel, which is characterized by 16% chromium and 0% nickel. For steel, this steel can be traced both chemical composition and equivalents.

Similarly for steel 18/10, AISI 304, 1.4301.

In the first case, we measured only ~ 12%, nickel none, in the second case ~ 18% chromium and ~ 8% nickel for the bottom material of the vessel made of ferritic stainless steel.

Fig. 3 – X-ray analysis of the bottom of the vessel                Fig. 4 – X-ray analysis of the pot

For bottom material, this is quite clear. What it should be, it is not. It’s a little different with the material of your own pot. Although the steel should have 18% chromium and 10% nickel, if I convert it to the applicable standards for 1.4301 steel then the allowable range for nickel says it should be in the range of 8 to 10.5%. According to the standard, we are therefore at the lower limit of the permitted range, but still within tolerance, but according to the composition announced by the seller, we are 2% below the notified nickel content.

So how do you deal with that?

According to the Civil Code No. 89/2012 Coll.

Article 2079

Basic provision,

(1) By the purchase contract, the seller undertakes to hand over the thing that is the subject of the purchase to the buyer and to enable him to acquire ownership of it, and the buyer undertakes to take over the thing and pay the purchase price to the seller.

Article 2095

The seller hands over the object of purchase to the buyer in the agreed quantity, quality and design.

However, since in this case it is not a defect, neither obvious nor hidden, but the delivery of goods in a different quality than agreed, this situation can rather be assessed according to the Consumer Protection Act No. 634/1992 Coll.

The bottom material is a completely different material than the one notified. In the case of the pot itself, even if the nickel content of 8% fits the above standard, the seller, respectively. The producers clearly state that this is 18/10 material, ie 10% nickel, and the fact that it is only 8% is in direct conflict with this claim. The declaration of conformity of the product should therefore state that the material is 18/8 and not 18/10. But that did not happen.

Citation from Act No. 634/1992 Coll

Article 5

Deceptive actions

(1) A commercial practice is considered to be misleading if it contains factually incorrect information and is therefore untrue, which leads or may lead the consumer to a purchase decision that he would not otherwise have made.

Information obligations

Article 9

(1) The seller is obliged to duly inform consumers about the properties of the products sold or the nature of the services provided, the method of use and maintenance of the product and the dangers arising from its incorrect use or maintenance, as well as the risk associated with the service. If necessary with regard to the nature of the product, the method and time of its use, the seller is obliged to ensure that this information is included in the enclosed written instructions and that it is understandable.

So what does this mean? Perhaps it’s just that if we feel that something with the goods we bought is not correct, it is worth considering all the circumstances and contradicting the purchase. In this case, the customer was very persistent and achieved his success. On the basis of an expert opinion, it was possible to prove that the seller, ie the supplier, did not deliver the goods in the notified quality. The Customer was reimbursed both the costs of the Goods and all other costs related to the complaint.

However, it should also be added that the non-certified measurement that was initially performed must be considered as indicative. Just because it can be disputed in the complaint procedure. However, the second measurement, this time already performed by a certified laboratory, was recognized as valid with regard to the round stamp of the testing laboratory, and no such objections can be raised against such a measurement.

February 9  2022

Yours, Jirka Stanislav