Material Of Stainless Steel Heating Elements
Due to the different purposes of each product, the quality requirements of the processing technology and raw materials are also different. -Generally speaking, different stainless steel products require different thickness tolerances of raw materials. The thickness tolerance of the second type of tableware and thermos cups is generally higher, which is -3~5%, while the thickness tolerance of the first type of tableware is generally required. -5%, steel pipe category requires 10%, hotel freezer material thickness tolerance is -8%, dealers generally require thickness tolerance between -4% and 6%. At the same time, the difference between the internal and external sales of the products will also lead to the different requirements of customers on the thickness tolerance of the raw materials.
① DDQ (deep drawing quality) material: refers to materials used for deep drawing (punching) purposes, which is what everyone calls soft materials. The main feature of this material is high elongation (≥53%) and hardness. Low (≤170%), the internal grain grade is between 7.0 and 8.0, and the deep drawing performance is excellent. Many companies that produce thermos flasks and pots have a relatively high product processing ratio (BLANKING SIZE/product diameter), and their processing ratios are 3.0, 1.96, 2.13, and 1.98, respectively. SUS304DDQ materials are mainly used for these products that require a higher processing ratio. Of course, products with a processing ratio of more than 2.0 generally require several passes of stretching to complete. If the extension of the raw materials cannot be achieved, the products are prone to cracks and pull-through phenomena when processing deep-drawn products, which affects the qualified rate of finished products, and of course increases the cost of the manufacturer;
②-General material: To be used for materials other than DDQ purposes, this material is characterized by relatively low elongation (≥45%), and relatively high hardness (≤180HB), and the internal grain size grade is 8.0~ Compared with the DDQ material, its deep drawing performance is relatively slightly worse than that of DDQ. It is mainly used for products that can be obtained without stretching, such as tableware, spoons, forks, and steel pipes for electrical appliances. But it has an advantage compared with DDQ material, that is, the BQ property is relatively better, which is mainly due to its slightly higher hardness.
Stainless steel sheet is an inexpensive material, but customers have very high requirements for its surface quality. Various defects such as scratches, pitting, sand holes, dark lines, creases, and pollution will inevitably appear in the production process of stainless steel sheets. Therefore, the surface quality, such as scratches, creases, etc., is a high-grade material. It is allowed, and the defect of pockmark sand hole is never allowed in spoons, spoons, forks, and making, because it is difficult to throw away when polishing. It is necessary to determine the quality level of the surface according to the degree and frequency of various defects on the surface, and thus to determine the product level.
