Is there anyone familiar with CSN material standards?

Here’s the little information I could find; take a look: http://www.metalnews.cn/gt/show-113496-1.html

Thank you to the person above; I’ve read it, but I’m still completely confused. :L

Czech steel grades still use the CSN standard designation system; CSN is the **standard code of former Czechoslovakia. In CSN standards, steel grades are typically represented by a six-digit sequence. The first digit of the grade, “4”, indicates metallurgical materials; for rolled and forged materials such as structural steel, stainless heat-resistant steel, and tool steel, this first digit “4” is omitted ； For metallurgical materials such as cast steel and cast iron, the first digit \"4\" in their grade numbers must never be omitted. For the aforementioned steels such as structural steel and stainless heat-resistant steel, when the first digit \"4\" in their grade numbers is omitted, their grade numbers actually become five-digit sequences. Among them: the combination of the first two digits indicates different types of steel (see Table 1-7). The third and fourth digits have different meanings depending on the type of steel. The fifth digit is the sequence number (or identifier). It should be noted that when writing or printing the steel grade, the first two digits of the five-digit code, which represent the series, should be separated from the latter three digits, for example 17 241. Table 1-7: Types of steel indicated by the combination of the first two digits in CSN steel grades. Combination of first two digits – Type of steel: 10, 11, 12–16, 17, 18, 19. Building steel, Steel for machinery manufacturing, High-quality structural steel, Stainless steel and heat-resistant steel, Products requiring further processing (such as metal wires, welding electrodes, etc.), Tool steel. Below is only an introduction to the methods used to denote the types of steel. (1) Stainless steel and heat-resistant steel. Examples: Note: ① If the first two digits of the steel grade are “17”, it indicates this type of steel (as shown in Table 1-7). ② The third digit of the steel grade indicates the various steel families within that category (see Table 1-8). ③ The fourth digit of the steel grade indicates the content of the main alloying element in the steel (see Tables 1-9 to 1-12). Additionally, for steel grades in category 17, such as 17 7××, the fourth and fifth digits range from 17 700 to 17 749; these represent steels with a higher nickel content, while those with values from 17 750 to 17 799 are steels with a higher manganese content. ④ The fifth digit of the steel grade is usually a sequence number related to the carbon content. ⑤ If necessary, an additional digit can be added after the fifth digit of the steel grade, separated by a dot. The heat treatment condition indicated by the additional digits is: 0—original state ； 1—Normalizing ； 2—Annealed ； 3—Spheroidizing annealed (for tool steel) ； 6—Quenched and tempered ； 9—Treated using special processes. Table 1-8: The steel series represented by the third digit in the stainless steel and heat-resistant steel grades according to the CSN standard. Series 17: 17 0××, 17 1××, 17 2××, 17 3××, 17 4××, 17 5××, 17 6××, 17 7××. Cr steel; Cr steel containing other elements (Al, Mo, Ni, etc.); CrNi steel with stabilizing elements (Ti, Nb, etc.); CrNi steel with stabilizing elements (Ti, Nb, etc.) and containing other elements (Mo, V, W, etc.); MnCr steel; Ni steel; Mn steel; MnNi steel. 17 8××, 17 9××. http://www.metalnews.cn/uploadfile/gt/uploadfile/200801/20080124064044865.gif: Steels with additional elements added as per specific requirements. Table 1-9: The chromium content indicated by the fourth digit in the grades 17 0××, 17 1××, 17 2××, 17 3×× of Series 17. Chromium content (%) in Cr steel and CrNi steel in Series 17: Cr steel: 4–6; CrNi steel: 6–10; 17×0×: 4–6; 17×1×: 6–10; 17×2×: 10–16; 17×3×: 10–16; 17×4×: 16–25; 17×5×: 16–25; 17×6×: >25; 17×7×: >25; 17×8×: –; 17×9×. Table 1-10: The manganese content indicated by the fourth digit in the grade 17 4×× of Series 17. Manganese content (%) in Cr steel and CrNi steel in Series 17: 17 40××: 6–10; 17 45××: 10–16; 17 41××: 10–16; 17 42××: 16–25; 17 43××: 16–25; 17 44××: >25. Table 1-11: The nickel content indicated by the fourth digit in the grade 17 5×× of Series 17. Nickel content (%) in MnCr steel in Series 17: Steels without additional elements: 6–10; Steels with additional elements: 10–16; 16–25; 25–40; >25. 17 50××, 17 51××, 17 52××, 17 53××, 17 54××, 17 55××, 17 56××, 17 57××, 17 58××, 17 59××. Table 1-12: The manganese content indicated by the fourth digit in the grade 17 6×× of Series 17. Manganese content (%) in Mn steel in Series 17: 17 60××: 6–10; 17 61××: 10–16; 17 62××: 16–25; 17 64××: >25. (2) Stainless and heat-resistant cast steels: As mentioned above, the grades for various cast steels in the CSN standard consist of six digits, as the first digit “4” cannot be omitted. For stainless and heat-resistant cast steels, the first three digits of their six-digit steel grades are all “422”; the steel series indicated by the fourth and fifth digits are shown in Table 1-13. The sixth digit is the serial number. When writing or printing the steel grade, the first two digits should be separated from the last four digits, for example: 42 2881. Table 1-13: The steel series represented by the fourth and fifth digits in the grades of stainless corrosion-resistant cast steel and heat-resistant cast steel according to CSN standards. For cast steel of category 422, the fourth and fifth digits indicate the steel series 42 288×42 289×Ni Al Cu; NiAl steel; Ni Co Al Cu steel with Nb and Ti added; 42 288×42 289×http://www.metalnews.cn/uploadfile/gt/uploadfile/200801/20080124064044738.gifNi Al Cu steel; NiAl steel; Ni Co Al Cu steel with Nb and Ti added; 42 290×42 291×42 292×42 293×42 294×42 295×42 299×Cr steel; CrSi steel; high-Mn steel; CrNi steel; CrNiMo steel; CrNiSi steel; CrWV steel