Because of the different uses of each product, its processing technology and raw material quality requirements are also different. Generally speaking, stainless steel products are different, its requirements for raw material thickness tolerance is also different, such as two types of tableware and thermos cup, thickness tolerance is generally higher, -3~5%, and a class of tableware thickness tolerance is generally required to -5%, steel pipe requirements -10%, hotel with refrigerator thickness tolerance requirements for -8%, The dealer's requirement for thickness tolerance is generally between -4% and 6%. At the same time, the different domestic and foreign sales of products will lead to the different requirements of customers on the thickness tolerance of raw materials. Generally, the thickness tolerance requirements of export customers are relatively high, while the domestic sales enterprises have relatively low requirements for thickness tolerance (mostly due to cost considerations), and some customers even require -15%.
①DDQ (deep drawing quality) material: refers to the material used for deep drawing (drawing) purposes, that is, the soft material, the main characteristics of this material is higher elongation (≧53%), lower hardness (≦170%), internal grain grade between 7.0~8.0, deep drawing performance is excellent. Many enterprises producing thermos bottles and POTS have relatively high processing ratio (BLANKING SIZE/ product diameter) of their products, reaching 3.0, 1.96, 2.13 and 1.98 respectively. SUS304DDQ MATERIAL is mainly used for these products requiring higher processing ratio, of course, the processing ratio of products more than 2.0 generally need to go through several stretches to complete. If the extension of raw materials is not up to the word, in the processing of deep draw products, the product is easy to crack, pull through phenomenon, affect the qualified rate of finished products, of course, it will increase the cost of the manufacturer;
② General material: It is mainly used for materials other than DDQ. The characteristics of this material are relatively low elongation (≧45%), relatively high hardness (≦180HB), internal grain grade is between 8.0 and 9.0, compared with DDQ materials, its deep drawing performance is relatively poor, it is mainly used for products that can be obtained without stretching. Like a kind of tableware spoon, spoon, fork, electrical appliances, steel pipe, etc. But it has an advantage compared with DDQ material, that is, BQ is relatively good, which is mainly due to its slightly higher hardness.
Stainless steel sheet is a kind of material with low price, but customers have very high requirements on its surface quality. Stainless sheet in the process of production inevitably appear all sorts of defects, such as scratches, pitting, sand hole, wiring, crease, pollution, etc., and its surface quality, like these defects such as scratch and crease is not allowed, senior material and pitting, sand hole defects in the spoon, spoon, fork, production is not allowed, because the polishing is very difficult to sell it. It is necessary to determine the quality grade of the surface according to the degree and frequency of various defects, so as to determine the grade of the product.
