What is the difference between ASTM -4 standards?

1 classification of ASTM standards ASTM standards are divided into the following six types. (1) Standard Test Method (standard test method) is a prescribed procedure adopted for identifying, testing and evaluating the quality, characteristics and parameters of materials, products, systems or services. (2) Standard Specification, which puts forward technical requirements and gives specific instructions for materials, products, systems or projects, and also puts forward the procedures that should be adopted to meet the technical requirements. (3) Standard Practice is a program that explains one or more specific operations or functions but does not produce test results. (4) Standard Terminology describes or defines nouns and explains symbols, abbreviations and acronyms. (5) Standard Guide: It selects a certain series or explains the usage, but does not introduce the specific implementation methods. (6) class Class．fication, which distinguishes and classifies materials, products, systems or specific services according to their sources, compositions, properties or uses.

2 the expression form of ASTM standard ASTM standard is expressed by standard code+letter classification code+standard serial number+formulation year+standard English name. (1) If the standard serial number is followed by the letter M, it is the metric unit standard, and if it is not followed by the letter M, it is the English unit standard. (2) If there are brackets behind the formulation year, the bracket year indicates the year when the standard was re-approved. (3) If there are A, B, C after the year of formulation, it means the revision number of the standard. (4) If there are ￡1, ￡2, ￡ 3 ...................................................................................................................................... Non-destructive testing, statistical methods, etc.) F——Corrosion, deterioration and degradation of special-purpose materials (electronic materials, earthquake-proof materials, medical surgical materials, etc.) 3 ASTM standard publications There are more than 11, standards in use, which are published in more than 7 Volume in 15 Section (excluding indexes) in the ASTM standard yearbook every year. These 15 categories are: index O1. Steel products O2. Nonferrous metals O3. Metal test methods and analysis procedures O4. Building materials O5. Petroleum products, lubricants and mineral fuels O6. Paints, related coatings and aromatic compounds O7. Textiles O8. Plastics O9. Rubber 1. Electrical insulators and electronic products 11. Water and environmental technology 12. Nuclear energy, solar energy and geothermal energy 13. Medical equipment and services 13.