What Are The Commonly Used Materials For Making Stainless Steel Coils?

Due to different uses of stainless steel coil products, the processing technology and quality requirements of raw materials are also different. Generally speaking, different stainless steel products require different thickness tolerances of raw materials. For example, class II tableware and thermos cups, the thickness tolerance is generally required to be - 3 ~ 5%, while the thickness tolerance of class I tableware is generally required to be - 5%, steel pipe is required to be - 10%, and the thickness tolerance of materials for hotel freezers is required to be - 8%.

Dealers' requirements for thickness tolerance are generally between - 4% and 6%. At the same time, the difference of domestic and export products will also lead to different requirements of customers for the thickness tolerance of raw materials. Generally, the thickness tolerance requirements of customers of export products are high, while the thickness tolerance requirements of domestic enterprises are relatively low (mostly due to cost considerations), and some customers even require - 15%.

1. DDQ (deep drawing quality) material: refers to the material used for deep drawing (punching), that is, the so-called soft material. The main characteristics of this material are high elongation (≥ 53%), low hardness (≤ 170%), internal grain grade between 7.0 ~ 8.0, and excellent deep drawing performance. The processing ratio (blank size / product diameter) of many enterprises producing thermos bottles and pots is generally high, and their processing ratios are 3.0, 1.96, 2.13 and 1.98 respectively.

Sus304ddq materials are mainly used for these products requiring high processing ratio. Of course, products with processing ratio more than 2.0 generally need to be stretched for several times. If the extension of raw materials cannot be reached, the products are easy to crack and pull through when processing deep drawn products, which will affect the qualified rate of finished products and, of course, increase the cost of manufacturers;

2. General material: it is mainly used for materials other than DDQ. This material is characterized by relatively low elongation (≥ 45%), relatively high hardness (≤ 180hb) and internal grain size grade of 8.0 ~ 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, such as spoons, spoons, forks, electrical appliances, steel pipes, etc. However, compared with DDQ material, it has an advantage that BQ property is relatively good, which is mainly due to its slightly higher hardness.

Stainless steel coil is a low price material, but customers have very high requirements for its surface quality. In the production process of stainless steel sheet, various defects will inevitably appear, such as scratch, pitting, sand hole, dark line, crease, pollution, etc., so its surface quality, such as scratch, crease and other defects are not allowed for high-grade materials, and pitting and sand hole defects are also not allowed in spoon, spoon, fork and production, because it is difficult to throw them away during polishing. It is necessary to determine the surface quality grade according to the degree and frequency of various surface defects, so as to determine the product grade.