Questions about 304 and S30408 materials

Personally, I think it’s not appropriate; one should be more thorough and follow the standards.

This post was last edited by sloosp on 2012-8-30 at 11:04. The standards for 304 stainless steel sheets are as follows: in GB/T4237-1992 it is designated as 0Cr18Ni9; in GB/T4237-2007 it is labeled 06Cr19Ni10; and in GB24511-2009 it is referred to as S30408/06Cr19Ni10. In reality, these all refer to the same material – only the standards have changed, the names have changed, and there have been slight adjustments to the composition. In the new standards of 2009, 06Cr19Ni10 replaced 0Cr18Ni9, just as Q345R replaced the previous 16MnR. It’s just a different name; however, steel pipes are still mostly made from the 0Cr18Ni9 grade, while plates are mostly made from the 06Cr19Ni10 grade. For plates, write S30408 or 06Cr19Ni10; for pipes, write 06Cr19Ni10. As for fasteners, I think it should be indicated as A2-70, A2-50, or 304, etc., in accordance with the fastener specifications.

This post was last edited by zhjn1967 on 2012-8-30 at 11:51. The method of representing alloy grades using element symbols has the disadvantages of being complex and time-consuming, having variable numbers of digits, and lacking a uniform format, which makes it difficult for computers to search for information and process it. To meet the needs of modern management, in 1998, **issued GB/T17616-1998 \"Unified Numerical Code for Steel and Alloy Grades\", abbreviated as \"ISC\". This standard stipulates that all steel and alloy products listed in ** and industry standards must be accompanied by both their product grades and unified numerical codes, which are to be used in conjunction for mutual reference and effectiveness. The unified digital code format is fixed at 6 digits, with a letter as the prefix followed by 5 Arabic digits. The initial letter represents different types of steel products; it is usually the first letter of an English word. For example, “S” stands for stainless steel, while “A” stands for alloy steel ； The second digit is the classification code; for example, “S3” denotes austenitic stainless steel, while the following four digits represent the sequential coding of the steel grade. Each unified numerical code can only be applied to one product grade; even if that product grade is no longer in use, the corresponding unified numerical code cannot be assigned to other grades. The unified numerical code is S30408, which indicates an austenitic stainless steel, with the sequential number being 0408. The new grade is 06Cr19Ni10, while the old grade is 0Cr18Ni9. It is the most commonly used austenitic stainless steel. Although the ISC standards stipulate that **steel and alloy products specified by standards and industry standards must be assigned both a product grade and a unified numerical code, compliance with this requirement is poor. Although unified numerical codes seem simple, the human brain is different from a computer – it cannot remember that many numbers. They are not as intuitive and easy to recall as product codes represented by element symbols. As a result, the use of unified numerical codes has not become widespread and is not well-known. This has even led to inconsistencies and confusion in standard references; for example, in GB/T20878-2007, “06Cr13” corresponds to the unified numerical code “S41008” and is classified as a martensitic stainless steel, whereas in GB/T24511-2009, “06Cr13” corresponds to the unified numerical code “S11306” and is classified as a ferritic stainless steel. For another example, the designation “015Cr21Ni26Mo5Cu2” in GB/T 20878-2007 corresponds to the unified numerical code “S31782”; however, the same designation in GB 24511-2009 corresponds to the unified numerical code “S39042”. How can there be any talk of the \"uniqueness of unified numerical codes\"? This is undoubtedly a tragedy in China’s work on standardizing metal materials. It’s better not to bother with any unified numerical codes at all. But when it comes to grade designations, it’s a real headache – having to take in elements from the United States, some from Europe, and also refer to ISO standards; it’s all so complicated that nothing seems to fit together. It’s even amusing to see the huge differences in the ways in which the old and new standards denote these materials; for example, the old standard uses 2Cr13, while the new standard uses 20Cr13. Although it’s the same material, the way the carbon content is indicated differs by a factor of ten. Why wasn’t the classification clear from the start when giving them names?

The key is to use the standard that you are applying; by following that standard, there will definitely be no problems

I remember that S30408 is not included in the standards for pressure vessels; it seems to be another grade instead

It’s understandable to want to understand it, but as for taking action, it depends on what the standards committee decides. . . . The materials are so messy

Check the reference standards in the details column; following the format specified in those standards will ensure accuracy. I understand what the original poster means, but I don’t agree with their approach

It’s generally better to use an S prefix; this way, the specific composition can be found by referring to the standard year

Write the stainless steel grade according to the village material standards. For example, for pipes, GB13296 corresponds to the grade 0Cr18Ni9; GB24511 corresponds to S30408 or 06Cr19Ni10. If this is written incorrectly, and if one is strict about it, then such a grade does not exist in the standards, which means it is an error

The new standard has been changed; the one in GB150-2011 is S30408