Stainless steel production materials

Due to different uses, each product has different processing techniques and quality requirements for raw materials. Generally speaking, different types of stainless steel products require different thickness tolerances for raw materials, such as Class II tableware and insulation cups. The thickness tolerance is generally high, ranging from -3% to 5%. For Class I tableware, the thickness tolerance is generally -5%, for steel pipes -10%, for hotel refrigerators -8%, and for distributors, the thickness tolerance is generally between -4% and 6%. At the same time, the differences in product sales both domestically and internationally can also lead to different customer requirements for raw material thickness tolerances. Generally, customers of export products have higher requirements for thickness tolerance, while domestic enterprises have relatively lower requirements for thickness tolerance (mostly due to cost considerations), with some customers even requiring -15%.
① DDQ (deep drawing quality) material: refers to a material used for deep drawing (drawing), 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. The processing ratio (BLANKING SIZE/product diameter) of many enterprises producing Vacuum flask and pans is generally high, and their processing ratios are 3.0, 1.96, 2.13 and 1.98 respectively. SUS304DDQ materials are mainly used for products with high processing ratios. Of course, products with a processing ratio exceeding 2.0 generally require several passes of stretching to complete. If the raw material extension cannot be achieved, the product is prone to cracking and pulling through during the processing of deep drawn products, which affects the qualified rate of the finished product and increases the cost of the manufacturer;
② General material: 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, forks, electrical appliances, steel pipes, etc. of a type 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. During the production process of stainless steel sheets, various defects such as scratches, pits, sand holes, dark lines, creases, and contamination are inevitable. As a result, surface quality defects such as scratches and creases are not allowed in high-grade materials, and defects such as pits 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 grade.