It is said that iron pot cooking is delicious. Why doesn't the rice cooker on the market have a cast iron liner?

From the material point of view, it is better to use refined iron. In terms of workmanship, fine steel is better. What kind of rice cooker liner is the best? 1. Aluminum liner has uniform heat conduction, easy molding and beautiful appearance, and can be compounded with other metals or alloys. It is the main material of mid-range cookware. However, the aluminum liner can't directly contact with food and must be protected at one time. Techniques such as thinning and stretching are often used to manufacture aluminum gaskets. This technology can keep the thickness of the pot rim and bottom, save materials and make the inner container look thicker. Second, the popular words "thick pot" and "thick pot" liner refer to the liner whose bottom and wall are made of thick metal materials. Because food transfers heat through the liner, under certain conditions, the transferred heat is directly proportional to the heat transfer area, that is, the heat transfer effect of the liner is directly proportional to the thickness of the liner. Only when the thickness of the inner container reaches 3-4 mm can the heat transfer channel needed for cooking food be fully satisfied, and the effect of Shi Dingjia's "delicious rice and meat" can be achieved. If the thickness of the inner container does not reach 3-4 mm, it cannot be called a real "thick kettle". 3. The popular word "honeycomb" of the liner means that the hot lines of the liner are designed in a honeycomb arrangement, which can make heat convection more sufficient and improve energy efficiency than the traditional planar liner. Fourth, it is best to use 304 plate for stainless steel liner. 304 stainless steel has excellent corrosion resistance and better intergranular corrosion resistance. Generally, 4L inner containers are made of about 0. 5 plates, and 5L and 6L inner containers are made of about 0. 8 plates. 202 plate will be used to process slightly inferior stainless steel liner, and the rust prevention ability of 202 plate is slightly worse than that of 304 plate. The stainless steel liner at the lower end is 20 1 plate. Because the 20 1 stainless steel that can be purchased in China at present is difficult to meet the National Hygienic Standard for the Dissolution of Harmful Metals from Stainless Steel Tableware Containers, the stainless steel rice cooker with extremely low price must be carefully selected. 5. The popular word "double bottom" in the liner is due to the poor thermal conductivity of stainless steel. In order to make up for this deficiency, it is necessary to lay another layer of aluminum on the outside of the bottom and cover it with a layer of stainless steel as the surface layer. The inner container adopting this treatment method is usually called "double bottom". 6. Ceramic (purple sand) inner container Purple sand belongs to pottery and is a safe inorganic material. The inner container made of purple taro is rich in natural iron, zinc, calcium and other trace elements, which is beneficial to human health. The cooked food tastes good, the surface is super hard and wear-resistant, acid and alkali resistant, corrosion resistant and good in heat preservation.