Aluminum 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 cannot directly contact with food, and the surface must be protected.
Most of the aluminum plates used to make the liners are 3003 aluminum plates, and ordinary rice cooker liners with specifications of 3L and 4L are made of plates with the thickness of 1.5- 1.6 mm, and plates with the thickness of 1.8-2.2 mm are used for 5L and 6L pots.
Thinning and stretching technology is often used in the manufacture of aluminum liner, which can keep the necessary thickness of the pot edge and bottom, and the liner looks thicker on the premise of saving materials.
2, stainless steel
The best stainless steel liner is made of 304 plate, which has excellent corrosion resistance and intergranular corrosion resistance. Generally, 4L cylinder liners are made of about 0.5 plates, and 5L and 6L cylinder liners 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.
Stainless steel liner can be used directly without surface treatment. But the stainless steel surface is not sticky, especially when cooking.
3. Composite multilayer materials
Composite multi-layer material lining is made of many materials, which can be basically divided into the following categories:
The inner surface of the double-layer ("steel" refers to stainless steel) composite plate liner is stainless steel, which not only meets the requirement of stainless steel on the inner surface, but also utilizes the integral heat soaking effect of aluminum to improve the thermal conductivity of stainless steel.
The inner wall of the liner is made of aluminum and the outer layer is made of stainless steel. The surface of inner aluminum can't directly contact with food, so it needs to be treated with performance protection to ensure food hygiene and improve non-stickiness.
The steel-aluminum-steel three-layer composite liner is made of stainless steel inside and outside, with an aluminum interlayer in the middle. Because the inner wall of the liner is stainless steel, the surface of the liner does not need to be protected. Lined with pure copper layer to further improve thermal conductivity. There are also some methods to add a hollow layer in the composite multilayer material to reduce the heat loss and save energy when IH heats the inner layer, but the induction layer must be inside the hollow layer. In addition, the glass bead or ceramic bead coating can be applied to the thermal insulation external coating to reduce heat loss to the outside and save energy. However, this kind of composite multi-layer liner is basically used in high-end products, and the price of products is basically above dry yuan.
4, ceramics (purple sand)
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, and the surface is super hard and wear-resistant, acid and alkali-resistant, corrosion-resistant and good in heat preservation.