The main production materials of stainless steel

Due to different uses, each product has different processing techniques and quality requirements for raw materials. Generally speaking, different stainless steel products require different thickness tolerances for raw materials. For example, for Class II tableware and insulated cups, the thickness tolerance is generally required to be high, ranging from -3% to 5%. For Class I tableware, the thickness tolerance is generally required to be -5%, for steel pipes -10%, for hotel refrigerators, the thickness tolerance is required to be -8%, and for distributors, the thickness tolerance is generally between -4% to 6%. At the same time, the difference in product sales both domestically and internationally can also lead to different customer requirements for the thickness tolerance of raw materials. The thickness tolerance requirements of general export product customers are relatively high, while domestic sales enterprises have relatively low thickness tolerance requirements (mostly due to cost considerations), and some customers even require -15%.

① DDQ (deep drawing quality) material: refers to a material used for deep drawing (punching) purposes, also known as soft material. The main characteristics of this material are high elongation (≥ 53%), low hardness (≤ 170%), internal grain grade between 7.0 and 8.0, and excellent deep drawing performance. Many enterprises that produce thermos bottles and pots generally have higher processing ratios (BLANKING SIZE/product diameter), with processing ratios of 3.0, 1.96, 2.13, and 1.98, respectively. The SUS304DDQ material is mainly used for products that require high processing ratios. Of course, products with processing ratios exceeding 2.0 generally require several stretches to complete. If the extension of raw materials cannot be achieved, the product is prone to cracking and tearing during the processing of deep drawn products, which affects the qualified rate of finished products and increases the cost for manufacturers;

② General materials: mainly used for materials other than DDQ purposes. The characteristics of this material are relatively low elongation (≥ 45%), relatively high hardness (≤ 180HB), and internal grain size grade 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, such as spoons, spoons, forks, electrical appliances, steel pipes, etc. for a class of tableware. But it has an advantage compared to DDQ materials, which is that its BQ properties are relatively better, mainly due to its slightly higher hardness.

Stainless steel sheet is a low-cost material, but customers have very high requirements for its surface quality. Various defects such as scratches, pitting, sand holes, dark lines, creases, and contamination are inevitable in the production process of stainless steel sheets. As a result, surface quality defects such as scratches and creases are not allowed in high-grade materials, and defects such as pitting and sand holes are also not allowed in spoons, spoons, forks, and production because it is difficult to remove them during polishing. It is necessary to determine the surface quality level based on the degree and frequency of various surface defects, in order to determine the product level.