First, the general characteristics of 304 stainless steel 1, a beautiful surface and the possibility of diversification 2, good corrosion resistance, durable than ordinary steel 3, good corrosion resistance 4, high strength, and thus the possibility of using a large plate 5, resistant High temperature oxidation and high strength, so it can resist fire 6, room temperature processing, that is easy to plastic processing 7, because no surface treatment, it is simple, easy to maintain 8, clean, high finish 9, good welding performance
Second, quality requirements characteristics of the micro project
(1) Material:
1DDQ (deep drawing quality) material: refers to the material used for deep drawing (redrawing), which is what we call soft material. The main characteristic of this material is its high elongation (?53%) and hardness Low (?170%), internal grain grade between 7.0-8.0, excellent deep draw performance. At present, many companies that produce thermos and pots have generally higher processing ratios (BLANKING SIZE/product diameter), and their processing ratios are 3.0, 1.96, 2.13, and 1.98, respectively. SUS304 DDQ material is mainly used for these higher processing ratio products, of course, the processing ratio of more than 2.0 products generally have to undergo a few passes to complete the stretch. If the raw material extension is not reachable, the product can easily produce cracks and pull-throughs when processing deep-drawing products, affecting the qualification rate of finished products, and of course increasing the cost of the manufacturers.
2 General materials Mainly used for materials other than DDQ applications, this material is characterized by a relatively low elongation (?45%), relatively high hardness (?180), and an internal grain size rating of 8.0-9.0. Compared with DDQ material, its deep drawing performance is relatively poor. It is mainly used for products that can be obtained without stretching, like spoons, spoons, forks, electrical appliances, and steel pipes for a type of tableware. However, it has an advantage over DDQ materials in that BQ properties are relatively good, mainly due to its slightly higher hardness.
(2) Surface quality:
Stainless steel sheet is a very expensive material, and the customer's surface quality requirements are also very high. However, various defects, such as scratches, pitting, creases, and contamination, are inevitably present in the production process of the stainless steel sheet, so that the surface quality, such as scratches, creases, and other defects, are either high or low. It is not allowed to appear, and pitting this kind of defect is never allowed in spoons, spoons, forks, and making, because it is difficult to throw away it during polishing. We determine the quality level of the table based on the extent and frequency of various defects on the surface to determine the product level.
(3) Thickness tolerance:
In general, different stainless steel products require raw material thickness tolerances are also different, like the second-class tableware and insulation cups, thickness tolerances generally require a higher, -3-5%, and a set of tableware thickness tolerances generally require - 5%, steel pipe requirements -10%, hotel refrigerator freezer material thickness tolerance requirement is -8%, dealers' thickness tolerance requirements are generally between -4%-6%. At the same time, the difference in the internal and external sales of the product will also lead to different requirements for the raw material thickness tolerance. The thickness tolerances of general export products customers are relatively high, but the thickness tolerance requirements of domestic sales companies are relatively low (mostly for cost considerations), and some customers even require -15%.
(4) Weldability:
The different requirements for the use of the product are different for the welding performance. A type of tableware generally does not require welding performance, and even includes some pot companies. However, most products require good welding performance of raw materials, such as second-class tableware, insulation cups, steel pipes, water heaters, drinking fountains and so on.
(5) Corrosion resistance:
The vast majority of stainless steel products require good corrosion resistance, such as Class I, Class II tableware, kitchen utensils, water heaters, drinking fountains, etc. Some foreign traders also perform corrosion resistance test on the product: heating with NACL solution to boiling, after a period of time Remove the solution, wash and dry, and weigh the weight to determine the degree of corrosion (Note: When the product is polished, the presence of Fe in the emery cloth or sandpaper will cause rust on the surface during the test).
(6) Polishing performance (BQ):
At present, stainless steel products are generally polished in the production process, and only a few products such as water heaters, drinking fountain liners, etc. do not need to be polished. Therefore, this requires good polishing properties of the raw materials. The following factors affect the polishing performance:
1 Raw material surface defects. Such as scratches, pits, pickling, etc. Raw material issues. Hardness is too low, it is not easy to polish when polishing (BQ is not good), and the hardness is too low, the surface of the orange peel is prone to occur when deep drawing, thus affecting the BQ. Hardness of BQ is relatively good. Deeply stretched products also have small black spots and RIDGING on the surface where the deformation is very large, which affects the BQ properties.
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