There are many kinds of metal materials for mechanical parts. In order to make production and management convenient and orderly, the relevant standards set different brand names for different metal materials, so as to show that they are unified and easy to adopt and use.
The method of indicating the brand of steel products (refer to GB/T221 - 2000)
- the basic profile of the standard
The GB/T221 - 2000 standard is released in April 1, 2000 after referring to the foreign steel products brand designation method and the domestic steel product designation method change (such as Q345 instead of 16Mn). It was launched in November 1, 2000 and implemented in November 1, 2000.
- changes in main technical content
(1) because some brands of iron and steel products have their own special standards, the brand names such as iron alloy, casting alloy, high temperature alloy, precision alloy, corrosion resisting alloy and cast iron, cast steel and powder material have been cancelled.
(2) the emergence of some new steel products, more improved the original standard. The new standard has increased decarbonization, low phosphorus granulated iron, vanadium pig iron, cast wear-resistant pig iron, guaranteed hardenability steel, non quenched and tempered mechanical structural steel, plastic mould steel and oriented silicon steel (Telecommunications).
(3) some of the steel grades that are not compatible with the development of science and technology and incompatible with production have been completely changed or modified. For example, carbon structural steel A3 is changed to Q235, low alloy high strength structural steel 16Mn is changed to Q345 and so on. The marking methods for stainless steel, heat-resistant steel and cold rolled silicon steel have also been modified.
(4) table 3 of the original standard "example of steel product brand representation" is deleted because it is not applicable to new standards.
The basic principle of the method of indicating the brand of steel products
(1) all the grades of iron and steel products in the national and industrial standards should be written in accordance with the GB/T221 - 2000 standard. All grades of steel products which are not prepared according to the regulations should be changed when the standard is revised. Some new steel products should also be written according to this brand.
(2) the expression of the brand name of the product is generally expressed in a combination of Chinese phonetic alphabets, chemical elements and Arabia numbers.
(3) when using Chinese phonetic alphabet to express product names, uses, characteristics and process methods, generally choose the first letter from the Pinyin of the product name. When you repeat the letters you choose with another product, you can use second letters or third letters, or select the first phonetic alphabet of two characters at the same time.
(4) the Chinese characters and Chinese phonetic alphabet are not available for the time being, and the symbols are English letters.
