Three grades of food grade stainless steel cutlery

Stainless steel cutlery can be divided into three grades: 430 (ie 18-0), 304 (18-8), and 316 (18-10). 430 stainless steel: It can prevent the oxidation caused by natural factors, but it can't resist the oxidation caused by the chemical substances in the air. After 430 stainless steel is not used for a period of time, it will still be oxidized (rusted) due to unnatural factors.

304 stainless steel: chemically resistant to oxidation. However, some areas with more serious pollution will have rust in 304.

316 stainless steel: more durable and more resistant.

Stainless steel is often classified according to the state of the organization: martensitic steel, ferritic steel, austenitic steel, and the like.

Martensitic stainless steel: high carbon content, high strength, hardness and wear resistance, but slightly poor corrosion resistance, can be adsorbed by magnets, and also cheap tableware.

Ferritic stainless steel: 12% to 30% chromium. Corrosion resistance and oxidation resistance are better, can resist the corrosion of atmospheric, acid and saline solution, high temperature oxidation resistance, mainly for industrial use, but also for tableware.

Austenitic stainless steel: containing more than 18% chromium, also contains about 8% of nickel and a small amount of molybdenum, titanium, nitrogen and other elements. It can withstand a variety of media corrosion, used in industrial pipelines, and will not be adsorbed by magnets.

Austenitic-ferritic duplex stainless steel: stainless steel with approximately half of austenite and ferrite structure, with two advantages, Cr content of 18%-28%, nickel Ni content of 3%-10% . For tableware making.

First, the specific standard (GB9684-88 stainless steel utensils container hygiene standards)

This standard specifies the sanitary requirements for stainless steel food containers.

This standard applies to all kinds of cookware, tableware, utensils and other food containers and machinery made of stainless steel.

1, appearance

The surface should be smooth and smooth.

2, material shake

2.1 All kinds of food storage containers and food processing machinery should use austenitic stainless steel.

2.2 All kinds of tableware: Martensitic stainless steel should be used.

3. Physical and chemical indicators

Physical and chemical indicators are shown in the table below.

Item Austenitic stainless steel Martensitic stainless steel

Lead (in Pb), mg/L, 4% acetic acid soaking solution ≤ 1.0 1.0

Chromium (in terms of Cr), mg/L, 4% acetic acid soaking solution ≤ 0.5

Nickel (in terms of Ni), mg/L, 4% acetic acid soaking solution ≤ 3.0 1.0

Tin (calculated as Cd), mg/L, ≤0.02 0.02 in 4% acetic acid solution

Arsenic (as As), mg/L, 4% acetic acid solution ≤0.04 0.04

Note: The soaking conditions are all boiled for 30 min and then at room temperature for 24 h.

Additional notes: This standard was proposed by the Department of Health and Epidemiology of the Ministry of Health.

This standard was drafted by Shanghai Food Hygiene Supervision and Inspection Institute.

This standard is interpreted by the Food Hygiene Supervision and Inspection Institute of the Ministry of Health, which is entrusted by the Ministry of Health.

Second, buy stainless steel tableware

Code standard

Generally, stainless steel cutlery is marked with 13-0, 18-0, and 18-8. The numbers in front of the three codes indicate the chromium content of the tableware, and the numbers in the back represent the nickel content. Heavy metals such as chrome are materials that prevent the product from rusting, while nickel content is a material that makes the product resistant to corrosion. At the time of purchase, you should pay attention to these details.

2. Packaging standards

When purchasing stainless steel cutlery, pay attention to the materials and steel grades used, and pay attention to whether the manufacturer's name and address of the manufacturer are indicated on the package, and there are some sanitary standards for the container.

3. Magnetic standards

Regular manufacturers generally use 304 (ie 18-8) and 430 (ie 18-0) stainless steel as a fork spoon, 420 (ie 13-0) as a knife, 430 and 420 are magnetic, 304 is micromagnetic. Therefore, when buying stainless steel cutlery, it can be easily judged by using a magnet.

At the same time, there are two kinds of stainless steels used in the production of stainless steel products, which are divided into "austenitic type" and "martensitic type". Some dishes and dishes are produced using "austenitic" stainless steel, and the knife and fork are used. It is produced using "martensitic" stainless steel. These two different stainless steels have fundamental differences. The "austenitic type" is stainless steel without magnetic properties, while the "martensitic type" is magnetic stainless steel.

4. Weight standard

The weight can be estimated by everyone, and when you buy the tableware, the good stainless steel tableware is generally heavier because the difference in material density is not so large, so the intuitive feeling is the feeling. Not the same, but the same thickness and shape of the tableware, high-grade materials and resisting materials will cause weight differences.

5. Price standard

This is a decisive factor for many consumers to buy goods. But when buying stainless steel cutlery, you should know that the price of good cutlery is not too low. Because it depends on the cost of the materials used to determine the price it sells, do not buy because of its low price, there are some inferior stainless steel tableware will affect the health of the human body.

Third, stainless steel tableware use precautions

1. It is not allowed to hold salt, soy sauce, vinegar, vegetable soup, etc. for a long time. Because these foods contain a lot of electrolytes, if they are kept for a long time, stainless steel will also react with these electrolytes like other metals to make them toxic. The metal element is dissolved.

2, should not use stainless steel pot Chinese medicine, because Chinese medicine contains a variety of alkaloids, organic acids and other ingredients, especially under heating conditions, it is difficult to avoid chemical reactions with it, but the drug fails, and even produces some toxicity Large complex.

3. Do not wash with strong alkaline or strong oxidizing chemicals such as baking soda or sodium hypochlorite. Because these materials are strong electrolytes, they also react electrochemically with stainless steel.

4, can not be empty. Compared with iron products and aluminum products, stainless steel cookware has low thermal conductivity and slow heat transfer time. The air burning will cause aging and falling off of the chrome plating on the surface of the cookware.

5, to keep the cookware clean, often scrub, especially after storing vinegar, soy sauce and other condiments should be washed in time to keep the cookware dry.

6. It is said that the composition and influence of stainless steel generally contain chromium and nickel. Chromium is a material that does not rust the product, and nickel is a corrosion-resistant material. If you use inferior stainless steel cutlery or use stainless steel cutlery in an inappropriate way, it may cause heavy metal harm to human health. You should pay attention to the parameters indicated above when purchasing.

Fourth, the characteristics

According to the arrangement of internal atomic structure, stainless steel can be divided into: body-centered cubic lattice structure (martensite), face-centered cubic lattice structure (austenite) and close-packed hexagonal lattice structure (ferrite). Austenite itself does not have magnetism, but the weight of machining is the basis of the magnetic size, but does not affect the corrosion resistance and other quality of stainless steel. Stainless steel is more and more popular because of its beautiful appearance, corrosion resistance and non-damage. There are more and more stainless steels used in pots and pans, urban sculptures, buildings, and decoration rooms.

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